Memory and learning impairments in deficit and non-deficit schizophrenia: a scoping review

Piotr Plichta; Monika Mak; Jerzy Samochowiec; Ernest M. Tyburski

doi:10.5114/ppn.2026.159800

eISSN: 2720-5371
ISSN: 1230-2813

Advances in Psychiatry and Neurology/Postępy Psychiatrii i Neurologii

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Review article

Memory and learning impairments in deficit and non-deficit schizophrenia: a scoping review

Piotr Plichta

¹

,

Monika Mak

¹

,

Jerzy Samochowiec

²

,

Ernest M. Tyburski

¹

Department of Health Psychology, Pomeranian Medical University in Szczecin, Poland
Department of Psychiatry, Pomeranian Medical University in Szczecin, Poland

Adv Psychiatry Neurol 2026; 28 (3): 28-51

DOI: https://doi.org/10.5114/ppn.2026.159800

Online publish date: 2026/03/12

Article files

- PPiN-00565-Memory.pdf [0.26 MB]

- Supplementary Tables.pdf [0.40 MB]

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INTRODUCTION

Schizophrenia is a complex neurodevelopmental disorder in which negative symptoms exert particularly detrimental and treatment-resistant effects [1, 2]. Within the negative-symptom spectrum, the deficit syndrome – first described by Carpenter et al. [3] – is defined by primary, enduring negative symptoms and is thought to arise from distinct pathophysiological mechanisms [4]. Emerging evidence indicates that this subtype is linked to more pronounced neurocognitive and social cognition deficits [5-8], poorer quality of life [9-11], and reduced social functioning [12, 13]. Nevertheless, the precise pattern of cognitive impairment in deficit schizophrenia remains contested, and no consensus has yet emerged as to whether any specific cognitive domain is disproportionately affected.

Memory impairments may be particularly important for patients’ daily functioning. Meta-analytic evidence shows marked deficits in both retrospective memory, i.e., the ability to recall past events and information [14-17], and prospective memory, i.e., the capacity to remember to carry out future intentions [18-21] in schizophrenia. Two analyses focusing on deficit schizophrenia found that verbal and non-verbal as well as working memory are somewhat more compromised in deficit than in non- deficit schizophrenia and substantially poorer than in healthy controls [6, 7]. Supporting this pattern, Kanchanatawan et al. [22] reported that episodic memory and delayed recall are more severely impaired in older adults with deficit schizophrenia than in those with amnestic mild cognitive impairment. Yet existing meta-analyses have not disentangled group differences in verbal versus non-verbal learning or in specific working-memory domains, leaving these questions unresolved.

The existing literature has broadened our understanding of cognitive impairments in deficit schizophrenia, yet the precise profile of memory impairment remains disputed – largely because theoretical frameworks and assessment paradigms vary across studies. In recent years, additional investigations have compared cognitive performance in deficit and non-deficit schizophrenia. An up-to-date scoping review can therefore clarify the neurocognitive distinctions – particularly in memory and learning – between these two clinical phenotypes. Accordingly, the current review sought to map the full breadth of published evidence and to describe the charac-teristics of studies that have examined memory and learning in patients with deficit and non-deficit schizophrenia as well as in healthy controls.

METHODS

This scoping review was designed to synthesize the existing evidence, identify knowledge gaps, and guide future research and clinical practice. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines (PRISMA 2020 [23]). The completed PRISMA checklist is provided in Supplementary Table 1.

Table 1

Memory and learning findings in deficit and non-deficit schizophrenia

Authors and year	Country	study design	sample	Age	Years of education	Gender	Diagnosis criteria	Assessment of deficit schizophrenia	Psychopatho-logical symptoms assessment	Analysis control	Cognitive domain	Measure	Main fundings	study quality
Wagman et al. (1987) [84]	USA	Cross-sectional	DS: n = 15 NDS: n = 15 HC: n = 15	DS: M = 27.9 NDS: M = 25.1 HC: M = 28.3	DS: M = 11.9 NDS: M = 12.5 HC: M = 15.8	DS: male = 13 NDS: male = 13 HC: male = 13	DSM-3	PDS	BPRS	- All groups were matched on age and gender - DS and NDS patients compared to HC had fewer years of education - ANCOVA was not used	Visual memory and learning	MFD	- No differences between DS and NDS patients - DS patients compared to HC had worse results	0.82
Buchanan et al. (1994) [68]	USA	Cross-sectional	DS: n = 18 NDS: n = 21 HC: n = 30	DS: M = 35.3 NDS: M = 32.3 HC: M = 34.2	DS: M = 11.4 NDS: M = 12.7 HC: M = 14.2	DS: male = 15 NDS: male = 17 HC: male = 20	DSM-3-R	SDS	BPRS	- All groups were matched on age and gender - DS and NDS patients compared to HC had fewer years of education - ANCOVA was used	Verbal memory and learning	WMS-R: LM, VPA	- No differences between DS and NDS patients in any test -DS and NDS patients compared to HC had worse results in all tests	0.93
Buchanan et al. (1994) [68]	USA	Cross-sectional	DS: n = 18 NDS: n = 21 HC: n = 30	DS: M = 35.3 NDS: M = 32.3 HC: M = 34.2	DS: M = 11.4 NDS: M = 12.7 HC: M = 14.2	DS: male = 15 NDS: male = 17 HC: male = 20	DSM-3-R	SDS	BPRS		WMS-R: VR, VPAS			0.93
Heckers et al. (1999) [76]	USA	Cross-sectional, neuroimaging	DS: n = 8 NDS: n = 8 HC: n = 8	DS: M = 40.0 NDS: M = 42.6 HC: M = 40.0	DS: M = 13.2 NDS: M = 12.8 HC: M = 14.9	N/A	DSM-4	SDS	PANSS, SANS	- All groups were matched on age - DS patients compared to HC had fewer years of education - ANCOVA was not used	Verbal memory and learning	MRET	- No differences between DS and NDS patients - DS and NDS patients compared to HC had worse results	0.86
Putnam and Harvey (2000) [73]	USA	Cross-sectional	DS: n = 25 NDS: n = 34	DS: M = 44.3 NDS: M = 43.8	DS: M = 11.5 NDS: M = 12.2	DS: male = 11 NDS: male = 15	DSM-3-R	PDS	PANSS	- Both groups were matched on age, years of education, and gender	Verbal memory and learning	WLL	- DS compared to NDS patients had worse results in all indices	0.89
Bryson et al. (2001) [52]	USA	Cross-sectional	DS: n = 33 NDS: n = 57	DS: M = 40.1 NDS: M = 42.5	DS: M = 12.0 NDS: M = 12.7	DS: male = 30 NDS: male = 53	DSM-3-R	SDS	PANSS	- Both groups were matched on age, years of education, and gender	Verbal memory and learning	WMS-R: LM, HVLT	- No differences between DS and NDS patients in WMS-R: LM, HVLT, and WAIS-R: DS -DS compared to NDS patients had worse results in WMS-R: FMS	0.95
											WMS-R: FMS
											WAIS-R: DS
Brazo et al. (2002) [75]	France	Cross-sectional	DS: n = 12 NDS: n = 14 HC: n = 35	DS: M = 37.5 NDS: M = 34.9 HC: M = 35.0	N/A	N/A	DSM-4	SDS	PANSS	- All groups were matched on age	Verbal memory and learning	CVLT	- No differences between DS and NDS patients in any index	0.91
													- DS patients compared to HC had worse
													results in most
													of indices
Galderisi et al. (2002) [54]	Italy	Cross-sectional	DS: n = 58 NDS: n = 54 HC: n = 26	DS: M = 35.2 NDS: M = 34.4 HC: M = 34.6	DS: M = 11.4 NDS: M = 11.3 HC: M = 12.7	DS: male = 43 NDS: male = 41 HC: male = 18	DSM-4	SDS	BPRS, SANS, SAPS	- All groups were matched on age, years of education, and gender - ANCOVA was used	Verbal memory and learning	AVLT	-No differences between DS and NDS patients in any test - DS and NDS patients compared to HC had worse results in all	1.00
											PMIT
											WAIS-R:
											working	DS	tests
											memory
Horan and Blanchard (2003) [69]	USA	Cross-sectional	DS: n = 15 NDS: n = 30 HC: n = 41	DS: M = 38.6 NDS: M = 32.0 HC: M = 38.3	DS: M = 12.3 NDS: M = 11.9 HC: M = 13.0	DS: male = 13 NDS: male = 24 HC: male = 35	DSM-4	SDS	BPRS	- All groups were matched on years of education and gender - NDS compared to DS patients and HC were younger - ANCOVA was not used	Verbal memory and learning	WMS-R: LM I, LM II	- No differences between DS and NDS patients in WMS-R: LM I, LM II, and VR II - DS compared to NDS	0.91
Horan and Blanchard (2003) [69]	USA	Cross-sectional	DS: n = 15 NDS: n = 30 HC: n = 41	DS: M = 38.6 NDS: M = 32.0 HC: M = 38.3	DS: M = 12.3 NDS: M = 11.9 HC: M = 13.0	DS: male = 13 NDS: male = 24 HC: male = 35	DSM-4	SDS	BPRS		WMS-R: VR I, VR II			0.91
													patients had worse results in
													WMS-R: VR I
													- DS and
													NDS patients compared to HC had worse
													results in all
													tests
Seckinger et al. (2004) [57]	USA	Cross-sectional	DS: n = 13 NDS: n = 33	DS: M = 33.1 NDS: M = 32.8	DS: M = 11.2 NDS: M = 12.9	DS: male = 11 NDS: male = 18	DSM-3-R	SDS	PANSS	- Both groups were matched on age and gender - DS compared to NDS patients had fewer years of education - ANCOVA was not used	Verbal working memory	WAIS-R: DS	- No differences between DS and NDS patients	0.86
Cohen et al. (2007) [7]	USA	Cross-sectional, meta-analysis	DS: n = 20 NDS: n = 25 HC: n = 25	DS: M = 40.8 NDS: M = 38.6 HC: M = 37.9	DS: M = 12.3 NDS: M = 11.9 HC: M = 13.0	DS: male = 18 NDS: male = 21 HC: male = 15	DSM-4	SDS	BPRS	- All groups were matched on age - DS and NDS patients compared to HC had fewer years of education - In DS and NDS patients, males predominated - ANCOVA was not used	Verbal memory and learning	WMS-R: LM, VPA	- No differences between DS and NDS patients in any test - DS and NDS patients compared to HC had worse results in all tests	0.95
Cohen et al. (2007) [7]	USA	Cross-sectional, meta-analysis	DS: n = 20 NDS: n = 25 HC: n = 25	DS: M = 40.8 NDS: M = 38.6 HC: M = 37.9	DS: M = 12.3 NDS: M = 11.9 HC: M = 13.0	DS: male = 18 NDS: male = 21 HC: male = 15	DSM-4	SDS	BPRS		WMS-R: FMS, VR, VPAS			0.95
Wang et al. (2008) [70]	China	Cross-sectional	DS: n = 30 NDS: n = 93 HC: n = 103	DS: M = 42.6 NDS: M = 42.7 HC: M = 40.9	DS: M = 10.3 NDS: M = 10.9 HC: M = 10.4	DS: male = 21 NDS: male = 64 HC: male = 71	DSM-4	SDS	BPRS, SANS, SAPS	- All groups were matched on age, years of education, and gender	Verbal memory and learning	WMS-R: LM	- No differences between DS and NDS patients in any test - DS and NDS patients compared to HC had worse results in all tests	1.00
Wang et al. (2008) [70]	China	Cross-sectional	DS: n = 30 NDS: n = 93 HC: n = 103	DS: M = 42.6 NDS: M = 42.7 HC: M = 40.9	DS: M = 10.3 NDS: M = 10.9 HC: M = 10.4	DS: male = 21 NDS: male = 64 HC: male = 71	DSM-4	SDS	BPRS, SANS, SAPS		WMS-R: VR			1.00
Cascella et al. (2008) [71]	USA	Cross-sectional	DS: n = 26 NDS: n = 79 HC: n = 316	DS: M = 35.1 NDS: M = 41.5 HC: M = 54.4	DS: M = 11.7 NDS: M = 12.1 HC: M = 14.3	DS: male = 20 NDS: male = 52 HC: male = 139	DSM-4	SDS	SANS, SAPS	- DS and NDS patients compared to HC were younger and had fewer years of education - In DS patients, males predominated - ANCOVA was not used - Demographically-adjusted T-scores (with age, years of education, and gender) used for domains	Verbal memory and learning	HVLT-R (test and subdomain)	- DS compared to NDS patients and HC had worse results in all indices of raw scores and both memory subdomains of T-scores - DS and NDS patients compared to HC had worse results in all indices of raw scores and both memory subdomains of T-scores; however NDS patients had similar results to HC in recognition parts	0.95
Cascella et al. (2008) [71]	USA	Cross-sectional	DS: n = 26 NDS: n = 79 HC: n = 316	DS: M = 35.1 NDS: M = 41.5 HC: M = 54.4	DS: M = 11.7 NDS: M = 12.1 HC: M = 14.3	DS: male = 20 NDS: male = 52 HC: male = 139	DSM-4	SDS	SANS, SAPS		BVMT-R (test and domain)			0.95
Réthelyi et al. (2012) [51]	Hungary	Cross-sectional	DS: n = 143 NDS: n = 123	DS: M = 38.7 NDS: M = 36.0	DS: M = 11.9 NDS: M = 13.5	DS: male = 64 NDS: male = 58	DSM-4	SDS	PANSS	- Both groups were matched on gender - DS compared to NDS patients where older and had fewer year of education - Regression model with covariates was used	Verbal memory and learning	RAVLT	- DS compared to NDS patients had worse results in both tests	0.95
Réthelyi et al. (2012) [51]	Hungary	Cross-sectional	DS: n = 143 NDS: n = 123	DS: M = 38.7 NDS: M = 36.0	DS: M = 11.9 NDS: M = 13.5	DS: male = 64 NDS: male = 58	DSM-4	SDS	PANSS		WAIS-R: DS			0.95
Pegoraro et al. (2013) [56]	Brazil	Cross-sectional	DS: n = 29 NDS: n = 44	DS: M = 34.4 NDS: M = 32.2	DS: M = 8.7 NDS: M = 10.3	DS: male = 24 NDS: male = 28	DSM-4	SDS	CDSS, SANS, SAPS	- Both groups were matched on age - DS compared to NDS patients had fewer years of education - In DS patients, males predominated - ANCOVA was used	Visual memory and learning	ROCF	- No differences between DS and NDS patients in WAIS-R: DS - DS compared to NDS patients had worse results in ROCF	0.91
Pegoraro et al. (2013) [56]	Brazil	Cross-sectional	DS: n = 29 NDS: n = 44	DS: M = 34.4 NDS: M = 32.2	DS: M = 8.7 NDS: M = 10.3	DS: male = 24 NDS: male = 28	DSM-4	SDS	CDSS, SANS, SAPS		WAIS-R: DS			0.91
Galderisi et al. (2013) [55]	Italy	Cross-sectional, longitudinal	DS: n = 51 NDS: n = 44	DS: M = 36.2 NDS: M = 34.7	DS: M = 11.1 NDS: M = 11.2	DS: male = 39 NDS: male = 34	DSM-4	SDS	BPRS, SANS, SAPS	- Both groups were matched on age, years of education, and gender	Verbal memory and learning	AVLT	- No differences between DS and NDS patients in any test	0.95
Galderisi et al. (2013) [55]	Italy	Cross-sectional, longitudinal	DS: n = 51 NDS: n = 44	DS: M = 36.2 NDS: M = 34.7	DS: M = 11.1 NDS: M = 11.2	DS: male = 39 NDS: male = 34	DSM-4	SDS	BPRS, SANS, SAPS		PMIT		- No differences between DS and NDS patients in any test	0.95
											learning
											WAIS-R: DS
											working
											memory
Csukly et al. (2014) [53]	Hungary	Cross-sectional	DS: n = 30 NDS: n = 28 HC: n = 29	DS: M = 36.6 NDS: M = 38.9 HC: M = 32.9	DS: M = 11.0 NDS: M = 14.0 HC: M = 14.2	DS: male = 12 NDS: male = 10 HC: male = 11	DSM-4	SDS	PANSS	- All groups were matched on age and gender - DS compared to NDS patients and HC had fewer years of education - ANCOVA was used	Verbal memory and learning	RAVLT	- No differences between DS and NDS patients in any test - DS patients compared to HC had worse	0.95
Csukly et al. (2014) [53]	Hungary	Cross-sectional	DS: n = 30 NDS: n = 28 HC: n = 29	DS: M = 36.6 NDS: M = 38.9 HC: M = 32.9	DS: M = 11.0 NDS: M = 14.0 HC: M = 14.2	DS: male = 12 NDS: male = 10 HC: male = 11	DSM-4	SDS	PANSS		WAIS-R: DS			0.95
													results in both
													tests
Chen et al. (2014) [61]	China	Cross-sectional	Drug naive: DS: n = 17 NDS: n = 32 HC: n = 57 Medicated: DS: n = 52 NDS: n = 56 HC: n = 128	N/A	N/A	N/A	DSM-4	SDS	PANSS	- All groups were matched on age, years of education, and gender	Verbal memory and learning	CogState: ISLT	Drug naive: - No differences between DS and NDS patients in any test - DS and NDS patients compared to HC had worse results in all	0.89
											CogState: OCL
											CogState: TWOB
											Visual working memory	CogState: CPAL	tests Medicated: - No
													differences
													between
													DS and NDS
													patients in any
													test
													- DS and
													NDS patients compared to HC had worse
													results in all
													tests
Domingo et al. (2015) [59]	Spain	Cross-sectional	DS: n = 453 NDS: n = 209	N/A	N/A	N/A	DSM-4	SDS	CGI-SCH	- ANCOVA was not used	Verbal memory and learning	WMS-3: LM	- DS compared to NDS patients had worse results in both tests	0.77
Domingo et al. (2015) [59]	Spain	Cross-sectional	DS: n = 453 NDS: n = 209	N/A	N/A	N/A	DSM-4	SDS	CGI-SCH	- ANCOVA was not used	LNST			0.77
Fervaha et al. (2016) [58]	Canada	Cross-sectional	DS: n = 144 NDS: n = 513	DS: M = 41.1 NDS: M = 41.3	DS: M = 11.7 NDS: M = 12.3	DS: male = 124 NDS: male = 370	DSM-4	PDS	CDSS, PANSS	- Both groups were matched on age - DS compared to NDS patients had fewer years of education - In DS patients, males predominated - ANCOVA was not used	Verbal memory and learning	HVLT	- DS compared to NDS patients had worse results in all tests	0.98
											LNST
											CTVWM
Sum et al. (2018) [11]	Singapore	Cross-sectional	DS: n = 27 NDS: n = 104 HC: n = 67	N/A	N/A	N/A	DSM-4	PDS	PANSS	- ANCOVA was used	Verbal memory and learning	BACS: LL	- No differences between DS and NDS patients in BACS: DST - DS compared to NDS patients had worse results in BACS: LL - DS and NDS patients compared to HC had worse results in both tests	1.00
Sum et al. (2018) [11]	Singapore	Cross-sectional	DS: n = 27 NDS: n = 104 HC: n = 67	N/A	N/A	N/A	DSM-4	PDS	PANSS	- ANCOVA was used	BACS: DST			1.00
Kanchana-tawan et al. (2018) [22]	Thailand	Cross-sectional	DS: n = 40 NDS: n = 40 MCI: n = 60 HC: n = 103	DS: M = 40.9 NDS: M = 41.3 MCI: M = 74.8 HC: M = 56.2	DS: M = 11.8 NDS: M = 12.8 MCI: M = 10.2 HC: M = 13.2	DS: male = 21 NDS: male = 22 MCI: male = 16 HC: male = 21	DSM-4-TR	SDS	N/A	- DS compared to MCI patients and HC were younger and compared only to HC had fewer years of education - NDS compared to MCI patients and HC were younger - In DS and NDS patients, males predominated - ANCOVA was used	Verbal memory and learning	WLM	- DS compared to NDS patients and HC had worse results in all indices - NDS patients compared to HC had worse results in all indices	1.00
Kanchana-tawan et al. (2018) [65]	Thailand	Cross-sectional	DS: n = 40 NDS: n = 40 HC: n = 40	DS: M = 40.9 NDS: M = 41.3 HC: M = 37.9	DS: M = 11.9 NDS: M = 12.8 HC: M = 14.3	DS: male = 21 NDS: male = 22 HC: male = 10	DSM-4-TR	SDS	PANSS, SANS	- All groups were matched on age and years of education - In DS and NDS patients, males predominated - ANCOVA was used	Verbal memory and learning	WLM	- DS compared to NDS patients and HC had worse results in all tests - DS and NDS patients compared to HC had worse results in all	0.93
											CANTAB: PAL
											CANTAB:
											working	SWM	tests
											memory
Tang et al. (2019) [60]	China	Cross-sectional	DS: n = 51 NDS: n = 58 HC: n = 40	DS: M = 50.2 NDS: M = 47.9 HC: M = 46.8	DS: M = 8.7 NDS: M = 8.8 HC: M = 10.1	DS: male = 51 NDS: male = 58 HC: male = 40	DSM-4-TR	SDS	BPRS, SANS, SAPS	- All groups were matched on age and gender - DS and NDS patients compared to HC had fewer years of education - ANCOVA was used	Verbal working memory	PASAT	- DS compared to NDS patients and HC had worse results in both indices - NDS patients compared to HC had worse	1.00
													results in both
													indices
Pan et al. (2020) [79]	China	Cross-sectional	DS: n = 41 NDS: n = 50 HC: n = 30	DS: M = 32.2 NDS: M = 33.8 HC: M = 35.8	DS: M = 5.1 NDS: M = 5.5 HC: M = 7.2	DS: male = 24 NDS: male = 26 HC: male = 16	DSM-4-TR	SDS	PANSS	- All groups were matched on age and gender - DS and NDS patients compared to HC had fewer years of education - ANCOVA was not used	Verbal memory and learning	RBANS: IM (subdomain)	- DS compared to NDS patients and HC had worse results in both subdomains - NDS patients compared to HC had worse	0.91
Pan et al. (2020) [79]	China	Cross-sectional	DS: n = 41 NDS: n = 50 HC: n = 30	DS: M = 32.2 NDS: M = 33.8 HC: M = 35.8	DS: M = 5.1 NDS: M = 5.5 HC: M = 7.2	DS: male = 24 NDS: male = 26 HC: male = 16	DSM-4-TR	SDS	PANSS		RBANS: DM (subdomain)			0.91
													results in both
													subdomains
Bryant et al. (2021) [81]	USA	Cross-sectional, neuroimaging	DS: n = 22 NDS: n = 39 HC: n = 59	DS: M = 23.3 NDS: M = 24.2 HC: M = 24.1	N/A	DS: male = 20 NDS: male = 20 HC: male = 38	DSM-4-TR	SDS	CDSS, BPRS	- All groups were matched on age - ANCOVA was used	Verbal memory and learning	RBANS: IM (subdomain)	- No differences between DS and NDS patients in both subdomains - DS and NDS patients compared to HC had worse	0.95
Bryant et al. (2021) [81]	USA	Cross-sectional, neuroimaging	DS: n = 22 NDS: n = 39 HC: n = 59	DS: M = 23.3 NDS: M = 24.2 HC: M = 24.1	N/A	DS: male = 20 NDS: male = 20 HC: male = 38	DSM-4-TR	SDS	CDSS, BPRS	- All groups were matched on age - ANCOVA was used	RBANS: DM (subdomain)			0.95
													results in both
													subdomains
Zhang et al. (2021) [74]	China	Cross-sectional	DS: n = 37 NDS: n = 49 HC: n = 80	DS: M = 50.0 NDS: M = 45.9 HC: M = 40.5	DS: M = 9.7 NDS: M = 10.4 HC: M = 13.8	DS: male = 37 NDS: male = 49 HC: male = 80	DSM-4	SDS	SANS, SAPS	- All groups were matched on gender - DS and NDS patients compared to HC were older and had fewer years of education - ANCOVA was used	Verbal memory and learning	MDRS-2: M (subdomain)	- DS compared to NDS patients and HC had worse results - NDS patients compared to HC had worse results	1.00
Wang et al. (2022) [80]	China	Cross-sectional	DS: n = 51 NDS: n = 90 HC: n = 67	DS: M = 29.9 NDS: M = 31.9 HC: M = 29.4	DS: M = 12.5 NDS: M = 13.5 HC: M = 13.6	DS: male = 24 NDS: male = 34 HC: male = 30	DSM-5	PDS	PANSS	- All groups were matched on age, years of education, and gender	Verbal memory and learning	RBANS: IM (subdomain)	- DS compared to NDS patients had worse results in RBANS: IM - DS and NDS patients compared to HC had worse results in both subdomains	1.00
Wang et al. (2022) [80]	China	Cross-sectional	DS: n = 51 NDS: n = 90 HC: n = 67	DS: M = 29.9 NDS: M = 31.9 HC: M = 29.4	DS: M = 12.5 NDS: M = 13.5 HC: M = 13.6	DS: male = 24 NDS: male = 34 HC: male = 30	DSM-5	PDS	PANSS		RBANS: DM (subdomain)			1.00
Liu et al. (2022) [13]	China	Cross-sectional	DS: n = 150 NDS: n = 140	DS: M = 49.5 NDS: M = 42.0	DS: M = 8.0 NDS: M = 9.0	DS: male = 114 NDS: male = 89	DSM-4	PDS	PANSS	- Both groups were matched on years of education - DS were older than NDS patients - In DS patients, males predominated - ANCOVA was not used	Verbal memory and learning	RBANS: IM (subdomain)	- DS compared to NDS patients had worse results in both subdomains	0.93
Liu et al. (2022) [13]	China	Cross-sectional	DS: n = 150 NDS: n = 140	DS: M = 49.5 NDS: M = 42.0	DS: M = 8.0 NDS: M = 9.0	DS: male = 114 NDS: male = 89	DSM-4	PDS	PANSS		RBANS: DM (subdomain)			0.93
Samocho-wiec et al. (2023) [82]	Poland	Cross-sectional	DS: n = 40 NDS: n = 42	DS: M = 46.3 NDS: M = 43.6	N/A	DS: male = 31 NDS: male = 23	DSM-4	SDS	CDSS, PANSS	- Both groups were matched on age - In DS patients, males predominated - ANCOVA was not used	Verbal memory and learning	RBANS: IM (subdomain)	- No differences between DS and NDS patients in RBANS: IM - DS compared to NDS patients had worse results in RBANS: DM	0.91
Samocho-wiec et al. (2023) [82]	Poland	Cross-sectional	DS: n = 40 NDS: n = 42	DS: M = 46.3 NDS: M = 43.6	N/A	DS: male = 31 NDS: male = 23	DSM-4	SDS	CDSS, PANSS		RBANS: DM (subdomain)			0.91
Bielecki et al. (2023) [62]	Poland	Cross-sectional	DS: n = 29 NDS: n = 44 HC: n = 39	DS: M = 38.6 NDS: M = 39.3 HC: M = 37.1	DS: M = 12.7 NDS: M = 13.5 HC: M = 14.6	DS: male = 22 NDS: male = 20 HC: male = 16	ICD-10	PDS	BNSS, PANSS, SNS	- All groups were matched on age - DS patients compared to HC had fewer years of education - In DS patients, males predominated - ANCOVA was used	Verbal working memory	LNST	- No differences between DS and NDS patients in both tests - DS patients compared to HC had worse results in LNST	1.00
Bielecki et al. (2023) [62]	Poland	Cross-sectional	DS: n = 29 NDS: n = 44 HC: n = 39	DS: M = 38.6 NDS: M = 39.3 HC: M = 37.1	DS: M = 12.7 NDS: M = 13.5 HC: M = 14.6	DS: male = 22 NDS: male = 20 HC: male = 16	ICD-10	PDS	BNSS, PANSS, SNS		WMS-R: SS			1.00
Plichta et al. (2023) [67]	Poland	Cross-sectional	DS: n = 29 NDS: n = 45 HC: n = 39	DS: M = 38.6 NDS: M = 39.3 HC: M = 37.1	DS: M = 12.7 NDS: M = 13.5 HC: M = 14.6	DS: male = 22 NDS: male = 21 HC: male = 16	ICD-10	PDS	BNSS, PANSS, SNS	- All groups were matched on age - DS patients compared to HC had fewer years of education - In DS patients, males predominated - ANCOVA was not used - Demographically-adjusted T-scores (with age, years of education, and gender) were used	Vermal memory and learning	MCCB: VerLM (subdomain)	- DS compared to NDS patients and HC had worse results in all memory subdomains of T-scores - NDS patients compared to HC had worse results in all memory subdomains of T-scores	1.00
											MCCB: VisLM (subdomain)
											MCCB: WM (subdomain)
Li et al. (2023) [63]	China	Cross-sectional, neuroimaging	DS: n = 33 NDS: n = 39 HC: n = 38	DS: M = 49.1 NDS: M = 45.9 HC: M = 46.1	DS: M = 8.2 NDS: M = 9.2 HC: M = 10.5	DS: male = 33 NDS: male = 39 HC: male = 38	DSM-4	SDS	PANSS	- All groups were matched on age and gender - DS patients compared to HC had fewer years of education - ANCOVA was used	Visual working memory	WMS-R: SS	- No differences between DS and NDS patients - DS and NDS patients compared to HC had worse results	1.00
Cyran et al. (2023) [77]	Poland	Cross-sectional	DS: n = 46 NDS: n = 73 HC: n = 120	DS: M = 45.6 NDS: M = 43.8 HC: M = 44.4	N/A	DS: male = 37 NDS: male = 36 HC: male = 71	DSM-4	SDS	CDSS, PANSS	- All groups were matched on age - In DS patients, males predominated - ANCOVA was used	Verbal memory and learning	RBANS: IM (subdomain)	- DS compared to NDS patients and HC had worse results in both subdomains - NDS patients compared to HC had worse results in both subdomains	1.00
Cyran et al. (2023) [77]	Poland	Cross-sectional	DS: n = 46 NDS: n = 73 HC: n = 120	DS: M = 45.6 NDS: M = 43.8 HC: M = 44.4	N/A	DS: male = 37 NDS: male = 36 HC: male = 71	DSM-4	SDS	CDSS, PANSS		RBANS: DM (subdomain)			1.00
Kowalski et al. (2023) [78]	Poland	Cross-sectional	DS: n = 44 NDS: n = 71 HC: n = 120	DS: M = 40.0 NDS: M = 45.0 HC: M = 43.5	N/A	DS: male = 35 NDS: male = 34 HC: male = 70	DSM-4	SDS	CDSS, PANSS	- All groups were matched on age - In DS patients, males predominated - ANCOVA was used	Verbal memory and learning	RBANS: IM (subdomain)	- DS compared to NDS patients and HC had worse results in RBANS: IM and compared to HC had worse results in RBANS: DM - NDS patients compared to HC had worse results in both subdomains	0.98
Kowalski et al. (2023) [78]	Poland	Cross-sectional	DS: n = 44 NDS: n = 71 HC: n = 120	DS: M = 40.0 NDS: M = 45.0 HC: M = 43.5	N/A	DS: male = 35 NDS: male = 34 HC: male = 70	DSM-4	SDS	CDSS, PANSS		RBANS: DM (subdomain)			0.98
Teles et al. (2024) [83]	USA	Cross-sectional, neuroimaging	DS: n = 18 NDS: n = 43 HC: n = 72	DS: M = 24.2 NDS: M = 24.0 HC: M = 23.8	N/A	DS: male = 17 NDS: male = 24 HC: male = 44	DSM-4	SDS	BPRS	- All groups were matched on age - In DS patients, males predominated - ANCOVA was used	Verbal memory and learning	RBANS: IM (subdomain)	- No differences between DS and NDS patients - DS and NDS patients compared to HC had worse results in both subdomains	0.95
Teles et al. (2024) [83]	USA	Cross-sectional, neuroimaging	DS: n = 18 NDS: n = 43 HC: n = 72	DS: M = 24.2 NDS: M = 24.0 HC: M = 23.8	N/A	DS: male = 17 NDS: male = 24 HC: male = 44	DSM-4	SDS	BPRS		RBANS: DM (subdomain)			0.95
Chengbing et al. (2024) [50]	China	Cross-sectional	DS: n = 100 NDS: n = 100	DS: M = 38.9 NDS: M = 38.5	DS: M = 10.5 NDS: M = 10.8	DS: male = 69 NDS: male = 54	DSM-4	PDS	PANSS	- Both groups were matched on age and years of education - In DS patients, males predominated - ANCOVA was not used	Verbal working memory	WAIS-R: DS	- DS compared to NDS patients and HC had worse results - NDS patients compared to HC had worse results	0.98
Gao et al. (2025) [72]	China	Cross-sectional, neuroimaging	DS: n = 35 NDS: n = 37	DS: M = 56.6 NDS: M = 54.7	DS: M = 8.0 NDS: M = 8.0	DS: male = 35 NDS: male = 37	DSM-4	SDS	BPRS, SANS, SAPS	- Both groups were matched on age, years of education, and gender	Verbal memory and learning	MDRS-2: M (subdomain)	- DS compared to NDS patients had worse results	0.89
Qi et al. (2025) [66]	China	Cross-sectional, neuroimaging	DS: n = 19 NDS: n = 19 HC: n = 30	DS: M = 31.0 NDS: M = 31.1 HC: M = 30.7	DS: M = 12.1 NDS: M = 12.1 HC: M = 12.5	DS: male = 15 NDS: male = 10 HC: male = 16	DSM-4	SDS	PANSS	- All groups were matched on age, years of education, and gender	Visual working memory	DT	- No differences between DS and NDS patients - DS and NDS patients compared to HC had worse results	0.91
Li et al. (2025) [64]	China	Cross-sectional, neuroimaging	DS: n = 44 NDS: n = 50 HC: n = 48	DS: M = 47.8 NDS: M = 47.5 HC: M = 45.0	DS: M = 8.7 NDS: M = 9.3 HC: M = 10.1	DS: male = 44 NDS: male = 50 HC: male = 48	DSM-4	SDS	PANSS	- All groups were matched on age and gender - DS and NDS patients compared to HC had fewer years of education - ANCOVA was used	Visual working memory	WMS-R: SS	- No differences between DS and NDS patients - DS and NDS patients compared to HC had worse results	1.00

[i] ANCOVA – analysis of covariance, AVLT – Auditory Verbal Learning Test, BACS – Brief Assessment of Cognition in Schizophrenia, DST – Digit Sequencing Task, LL – List Learning, BNSS – Brief Negative Symptom Scale, BPRS – Brief Psychiatric Rating Scale, BVMT-R – Brief Visuospatial Memory Test-Revised, CANTAB – Cambridge Neuropsychological Test Automated Battery, PAL – Paired-Association Learning, SWM – Spatial Working Memory, CogState: CPAL – Continuous Paired Association Learning Task, ISLT – International Shopping List Task, OCL – One Card Learning Task; TWOB – Two Back Task, CDSS – Calgary Depression Scale for Schizophrenia, CGI-SCH – Clinical Global Impression-Schizophrenia, CTVWM – Computerized Test of Visuospatial Working Memory, CVLT – California Verbal Learning Test, DS – Deficit schizophrenia, DSM-3/4/5/R/TR – Diagnostic and Statistical Manual – Third/Fourth/Fifth/Revised/Text Revision, DT – Detection Task. HC – Healthy controls, HVLT – Hopkins Verbal Learning Test, ICD-10 – International Classification of Diseases – Ten, LNST – Letter- Number Sequencing Test, M – Mean, MCCB – MATRICS Consensus Cognitive Battery: VerLM – Verbal Learning and Memory, VisLM – Visual Learning and Memory, WM – Working Memory, MCI – Mild cognitive impairment, MDRS-2 – Mattis Dementia Rating Scale – Second Edition: M – Memory, MFD – Graham-Kendall Memory for Designs, MRET – Memory Retrieval Experimental Task, n – population size, N/A – Not available, NDS – Non-deficit schizophrenia, PANSS – Positive and Negative Syndrome Scale, PASAT – Paced Auditory Serial Addition Test, PDS – Proxy for the deficit syndrome, PMIT – Picture Memory and Interference Test, RAVLT – Rey Auditory Verbal Learning Test, RBANS – Repeatable Battery for the Assessment of Neuropsychological Status: DM – Delayed Memory, IM – Immediate Memory, SANS – Scale for the Assessment of Negative Symptoms, SAPS – Scale for the Assessment of Positive Symptoms, SDS – Schedule for the Deficit Syndrome, SNS – Self-evaluation of Negative Symptoms, WLL – Word List Learning, WLM – Word List Memory, WAIS-R – Wechsler Adult Intelligence Scale – Revised, DS – Digit Span, WMS-R/3 – Wechsler Memory Scale – Revised/Third Edition: FMS – Figural Memory Subtest, LM – Logical Memory, SS – Spatial Span, VPA – Verbal Paired Associates, VPAS – Visual Paired Associates Subtest, VR – Visual Reproduction

Search strategy and study selection

To identify the relevant studies published between January 1980 and June 2025, a literature search was performed using the following databases: PsycINFO, ERIC, Health Source: Nursing/Academic Edition, and MEDLINE. To minimize bias, two independent researchers (P.P. and E.M.T.) performed an online search for papers using the combination of keywords as follows: (“deficit-schizophrenia” OR “non-deficit schizophrenia” OR “deficit syndrome”) AND (“memory” OR “learning” OR “cogn*” OR “neuropsychol*”). The search included analysis of title, abstract, and keywords; in addition, we also adopted extensive search techniques, such as checking reference lists and searching in Google Scholar.

The initial search results were imported into MS Excel. Two researchers (P.P. and E.M.T.) screened the titles and references and removed duplicates. Following the initial screening of 254 titles and abstracts based on the inclusion criteria, they convened to discuss disagreements and clarify criteria. After complete title and abstract screening, the full-text screening was conducted for all articles independently. Any disagreements about eligible articles were resolved by discussion with a third reviewer (M.M.). By consensus, we excluded seven articles [12, 24-29] because they relied solely on two instruments – the Block Design subtest of the WAIS-R and the Spatial Processing Test – that are designed chiefly to evaluate visuospatial ability. According to standard neuropsychological references [30, 31], these measures provide only limited information about visual memory and were therefore deemed insufficient for our purposes.

Eligibility criteria

The inclusion criteria were: (1) evaluation of memory or learning in deficit and non-deficit schizophrenia, comparison of the two groups or with a control group, (2) use of the Schedule for Deficit Syndrome (SDS) or a proxy measure based on other rating scales (PDS) for the status of deficit syndrome, and (3) the quality assessment of the study based on Kmet et al. [32] with a cut-off score of at least 0.65. Only peer-reviewed journal articles written in English and involving human participants were included. During the selection process (described in detail below), the authors removed articles that examined cognitive functions other than memory or learning that were not relevant to the main research aim. Furthermore, studies presenting identical results to those in previous articles were not included.

Data extraction and quality assessment procedures

Data extraction was conducted independently by two researchers (P.P. and E.M.T.). Data for extraction included the following: (a) study and sample characteristics (first author and year of publication, country, study design, sample size, age, years of education, gender), (b) details regarding schizophrenia (diagnostic criteria, assessment of deficit schizophrenia, assessment of psychopathological symptoms), and (c) cognitive assessment (analysis control, cognitive domain, measure, and main findings).

For evaluation of the quality of identified studies, a method proposed by Kmet et al. [32] was used. This method allows researchers to assess 14 criteria: objective, study design, group selection, participant characteristics, random allocation, blinding of investigators, blinding of subjects, outcome, sample size, analy-tic methods, estimate of variance, control of confounding variables, detail in reported results, and conclusions supported by the results. Each component is rated using a 3-point scale (2 for “yes”, 1 for “partial”, and 0 for “no”). As three criteria (referring to interventional studies: random allocation and two for blinding) were not applicable in our review, they were not taken into account when calculating the overall score. The cut-off was 0.65, which Kmet et al. [32] considered moderate. Two investigators (P.P. and E.M.T.) independently assessed the selected

39 studies. Next, the average of the two assessments was calculated for each study. No study had a score lower than 0.65 and no reports were excluded for this reason. The overall scores are presented in Table 1, while details of quality assessment are provided in Supplementary materials (Supplementary Tables 2-4).

Supplementary Tables

RESULTS

Study and sample characteristics

Thirty-eight records satisfied the eligibility criteria and were retrieved for full-text screening. Hand-searching the reference lists of two earlier meta-analyses [6, 7] yielded four additional papers, one of which met the inclusion criteria. In total, 39 full-text studies were included in this scoping review (Table 1). All employed cross- sectional designs (including seven that incorporated neuroimaging components; one was longitudinal) and were published between 1987 and 2025. Most originated from China (n = 12) or the United States (n = 11); the remainder were conducted in Poland (n = 5), Italy (n = 2), Hungary (n = 2), Thailand (n = 2), Canada (n = 1), Brazil (n = 1), France (n = 1), Singapore (n = 1) and Spain (n = 1). A flow diagram of the study-selection process is presented in Figure I.

Across the 39 studies included (Table 1), the samples comprised 2,088 participants with deficit schizophrenia, 2,685 with non-deficit schizophrenia, and 1,805 healthy controls. Descriptive characteristics were reported in most papers: age in 36 studies, years of education in 30, and gender distribution in 34. Mean age varied substantially – from 23.3 to 56.6 years in the deficit schizophrenia group, 24.0 to 54.7 years in the non-deficit schizophrenia group, and 23.8 to 56.2 years in the healthy controls. Years of education were likewise heterogeneous, ranging from 5.1 to 13.2 years in deficit schizophrenia, 5.5 to 14.0 years in non-deficit schizophrenia, and 7.2 to 15.8 years in the healthy controls. Five studies enrolled only males, and in 11 additional studies men constituted the majority of the deficit schizophrenia samples.

Twelve studies directly contrasted deficit schizophrenia and non-deficit schizophrenia groups; 27 also incorporated healthy controls. One study added a mild cognitive impairment comparison group, and another stratified schizophrenia participants into drug-naïve and medicated cohorts. Schizophrenia was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria in nearly all cases (DSM-3: n = 5; DSM-4: n = 31; DSM-5: n = 1), whereas only two studies used the International Classification of Diseases – Tenth Revision (ICD-10).

Clinical characteristics

In most of the studies included, patients were classified as deficit or non-deficit according to the original criteria of Carpenter et al. [3]. Thirty investigations employed the Schedule for Deficit Syndrome (SDS) [33], widely regarded as the field’s gold-standard instrument [34]. Nine others used a proxy for deficit syndrome (PDS), deriving symptom scores – typically from selected items of the Positive and Negative Syndrome Scale (PANSS) [35] – with minor methodological variations across authors. The PANSS – which captures positive, negative, and gene-ral psychopathology – was the most commonly applied instrument, either on its own (n = 15) or alongside other scales (n = 8). Additional measures included the Brief Psychiatric Rating Scale (BPRS) [36] (n = 11), Scale for the Assessment of Negative Symptoms (SANS) [37] (n = 10), Scale for the Assessment of Positive Symptoms (SAPS) [38] (n = 8), Calgary Depression Scale for Schizophrenia (CDSS) [39] (n = 6), Brief Negative Symptom Scale (BNSS) [40] (n = 2), Self-Evaluation of Nega-tive Symptoms (SNS) [41] (n = 2), and Clinical Global Impression-Schizophrenia (CGI-SCH) [42] (n = 1).

Control of confounding variables

Demographic matching varied widely across the studies included: five investigations matched all three groups – deficit schizophrenia, non-deficit schizophrenia, and healthy controls – on age, years of education, and sex, while four matched only the two patient groups. Among the remainder, seven studies matched for age and sex (six across all three groups and one across the patient groups), two matched for age and education (across all three groups), and one matched for education and sex (across all three groups); nine matched solely for age (seven across three groups and two across the patient groups), two matched solely for sex (one across two groups and one across three groups), and one matched solely for education (across two groups, see Table 1). Two studies provided no matching, and two others lacked sufficient demographic detail to determine matching status. To account for residual differences, 16 studies employed analysis of covariance (ANCOVA), two converted raw scores into demographically adjusted T-scores, and one applied multiple regression with covariates, all approaches consistent with best practice in neuropsychological research [43].

Measurement of memory and learning

The memory- and learning-assessment tools employ-ed in the studies included are summarized in Table 2. Guided by the classification schemes used in prior meta- analyses of memory in schizophrenia [14-16], we grouped each test according to (a) the modality of information processed (verbal vs. visual), (b) the memory system targeted (working vs. episodic), and (c) whether it captured learning. Most investigations derived measures from selected subtests of widely used neuropsychological batteries, most commonly the Wechsler Memory Scale – Revised or Third Edition (WMS-R/3) [44, 45] (n = 9), the Wechsler Adult Intelligence Scale – Revised (WAIS-R) [46] (n = 8), and the Cambridge Neuropsychological Test Automated Battery (CANTAB) [47] (n = 1). Eight studies used the full Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) [48], and two used the MATRICS Consensus Cognitive Battery (MCCB) [49]). A minority of studies relied on single stand-alone standardized tests or experimental paradigms.

Table 2

Memory and learning tests included in the scoping review

Cognitive domain/ Battery or single tool		Subtest or subdomain index	Brief description
Verbal memory and learning
	Brief Assessment	List Learning (LL)	Participants receive a list of 15 words and are instructed to freely recall as many
	of Cognition in Schizophrenia (BACS)		items as possible across 5 successive learning trials.
	California Verbal		Participants are presented a 16-word list and complete five successive learning trials,
	Learning Test (CVLT)		each followed by immediate free recall. A single presentation of a different 16-word
			interference list is then administered, after which its free recall is obtained.
			Free and category-cued recall of the original word list are evaluated both
			immediately after the interference phase and again following a 20-minute delay.
	CogState	International	Participants are exposed to a list of everyday grocery items across
	CogState	Shopping List Task	3 consecutive learning trials, with instructions to actively encode each word.
		Shopping List Task
		(ISLT)	Free recall is assessed immediately after the final presentation and once more following a 15-minute retention interval.
	Consortium to	Word List Memory	Participants study a series of 10 words across 3 learning trials, with item order shuffled
	Establish a Registry for	(WLM)	on each presentation. After every trial they freely recall as many words as they can.
	Alzheimer’s Disease (CERAD)		A delayed free-recall assessment is then conducted 5 minutes later to evaluate retention.
	Hopkins Verbal Learning		Participants hear a 12-word list consisting of semantically unrelated items
	Test/Revised (HVLT/R)		on 3 consecutive learning trials. Free recall is obtained immediately after
			each presentation, and memory for the same material is reassessed after
			a timed delay to gauge longer-term retention.
	MATRICS Consensus	Verbal Learning	The MCCB verbal learning subtest closely parallels the structure of the Hopkins Verbal
	Cognitive Battery	and Memory	Learning Test - Revised (HVLT-R). During each learning trial, participants
	(MCCB)	(VerLM)subdomain	hear the same list of 12 unrelated words and are subsequently required to recall as many items as they can.
	Mattis Dementia Rating	Memory (M)	This subdomain combines prose-recall and recognition tasks. Examinees restate
	Scale - Second Edition (MDRS-2)	subdomain	a spoken sentence both immediately and after a brief retention interval, then identify previously presented verbal or visual items among distractors.
			Orientation queries regarding person, place, and time are interwoven, yielding
			a comprehensive measure of episodic memory and situational awareness.
	Rey/Auditory Verbal		Participants hear a primary list of 15 words (List A) on 5 consecutive learning trials,
	Learning Test (R/AVLT)		each followed by immediate free recall. A second 15-word interference list (List B)
			is then administered once, after which recall for List A is reassessed both
			immediately and again following a delay, providing indices of learning,
			susceptibility to interference, and longer-term retention.
	Repeatable Battery	Immediate	The ability to remember information immediately after receiving it.
	for the Assessment	Memory (IM)	Includes scores calculated from 2 subtests: List Learning and Story Memory.
	of Neuropsychological	subdomain
	Status (RBANS)	includes:
		List Learning	Examinees hear a sequence of 10 semantically unrelated words on 4 successive
			learning trials. Following each presentation, they are prompted to freely recall
			as many of the items as possible, providing an index of immediate verbal
			learning efficiency.
		Story Memory	Participants listen to a brief vignette composed of 12 distinct words
			and are subsequently asked to recall as many of those words as possible,
			yielding a measure of immediate prose-learning ability.
	Wechsler Memory Scale	Logical Memory	Participants hear 2 brief narratives and are instructed to recount their content
	- Revised/Third Edition (WMS-R/3)	(LM)	immediately after each presentation and again following a 30-minute delay, allowing assessment of both immediate and delayed verbal recall.
		Verbal Paired	Examinees study 5 successive presentations of word pairs. Immediate associative
		Associates (VPA)	recall is obtained after each learning trial, and delayed recall is re-evaluated 30 minutes later to gauge longer-term retention of the pairings.
	Memory Retrieval		Participants first complete a baseline task in which they supply the first word that
	Experimental Task		comes to mind to finish three-letter stems displayed on screen. After an offline study
	(MRET)		phase presenting 100 randomized target words, they perform two retrieval
			conditions – “low recall” following shallow encoding and “high recall” following
			deep encoding – allowing frontal activity associated with weak recall to be
			contrasted with hippocampal activity linked to strong recall.
	Word List Learning (WLL)		Participants first study a list of 15 target words. During the subsequent retrieval phase,
			they are shown a longer list that intermixes the original items with semantically similar
			foils and must identify as many of the previously learned words as possible.
Visual memory and learning
	Brief Visuospatial		Participants study 6 geometric designs across three successive learning trials
	Memory Test – Revised		and reproduce the figures from memory immediately after each presentation
	(BVMT-R)		as well as following a 30-minute retention interval. The resulting drawings are rated for accuracy and spatial fidelity using standardized scoring criteria.
	Cambridge	Paired-	Several boxes are displayed concurrently on screen and are revealed one by one
	Neuropsychological	Association	in a random order, with only one box showing the target pattern.
	Test Automated Battery (CANTAB)	Learning (PAL)	After viewing, participants must indicate the box that initially contained the pattern.Performance is quantified by the total number of accurate selections.
	CogState	One Card	In this computerised task on each trial, a single playing card appears face-up
	CogState	Learning Task	at the centre of the screen, and participants judge whether that card has already
		Learning Task
		(OCL)	been shown during the current session. Instructions emphasise both speed and accuracy in responding.
	Graham-Kendall		Participants are shown 15 geometric figures that grow progressively more complex,
	Memory for Designs		each printed on a 9 × 12-inch card. The designs are presented one at a time
	(MFD)		in a predetermined order, remaining visible for 5 seconds before being withdrawn from view.
	MATRICS Consensus	Visual Learning	Individuals observe a 2 × 3 array of geometric figures for a 10-second exposure
	Cognitive Battery	and Memory	and are subsequently asked to reproduce the designs from memory.
	(MCCB)	(VisLM)subdomain	Performance is quantified by tallying, on each trial, both the number of correctly reproduced items and the accuracy of their spatial placement;these values are then aggregated to generate a total learning score.
	Picture Memory		Participants first study 20 target faces. The targets are subsequently combined with
	Interference Test (PMIT)		20 demographically matched distractor faces (similar in age, sex,
			and ethnicity), and recognition is probed immediately after learning and again
			after a 20-minute delay. Performance is scored by summing the number of targets
			correctly identified and distractors accurately rejected.
	Rey-Osterreith Complex		Participants initially copy a detailed geometric figure and subsequently redraw
	Figure (ROCF)		it from memory after both a brief 3-minute interval and a longer 30-minute delay, enabling assessment of immediate and delayed vasoconstrictive recall.
	Wechsler Memory Scale	Visual	Examinees view each of 5 geometric figures for 10 seconds and are subsequently
	- Revised/Third Edition	Reproduction	required to recreate the designs from memory, first immediately and then again
	(WMS-R/3)	(VR)	after a 25-minute retention interval, providing indices of both immediate and delayed visuospatial recall.
		Visual Paired	Participants view 6 abstract line figures, each linked to a distinct colour, across as
		Associates	many as 6 learning trials. After each presentation they must immediately report
		Subtest (VPAS)	the colour corresponding to every figure, and this associative recall is assessed again after a 30-minute retention interval to gauge longer-term memory.
		Figural Memory	Participants initially study a series of abstract designs; their recognition memory
		Subtest (FMS)	is then assessed by requiring them to discriminate these previously viewed figures from a larger array of novel foils.
Verbal and visual memory
	Repeatable Battery	Delayed Memory	A measure of delayed and recognition memory. It includes computed scores
	for the Assessment	(DM) subdomain	from 4 subtests: List Recall, List Recognition, Story Memory Recall, and Figure Recall.
	of Neuropsychological Status (RBANS)	includes:
	of Neuropsychological Status (RBANS)	List Recall	Participants attempt to retrieve as many items as possible from the word list that was introduced at the outset.
		List Recognition	Participants view a series of 20 words and must decide which of them were included in the initial study list presented at the start of the examination.
		Story Memory	Participants attempt to retrieve as many words as possible from the narrative
		Recall	that was presented at the beginning of the assessment.
		Figure Recall	Participants are instructed to reconstruct from memory a previously presented complex geometric figure by drawing it as accurately as possible.
Verbal working memory
	Brief Assessment of Cognition inSchizophrenia (BACS)	Digit Sequencing Task (DST)	This task requires participants to listen to sequences of numbers and recall them either in the original order (forward span) or in reverse order (backward span), depending on task instructions.
	CogState	Two Back Task (TWOB)	On every trial a playing card is displayed face-up at the centre of the screen; participants judge whether it is identical to the card presented two trials earlier, responding “Yes” for matches and “No” for non-matches. Task instructions stress both speed and accuracy of responding.
	Letter-Number Sequencing Test (LNST)		Participants hear randomized strings of letters and digits and must mentally reorganize each string - first repeating the numbers (in ascending order)and then the letters (in alphabetical order). The total score equals the number of sequences reproduced without error.
	Wechsler Adult Intelligence Scale -Revised (WAIS-R)	Digit Span (DS)	This task comprises two components. In the forward span, participants repeat sequences of digits exactly as spoken by the examiner. In the backward span, they reproduce each sequence in reverse order, requiring additional manipulation of working memory.
Visual working memory
	Cambridge Neuropsychological Test Automated Battery (CANTAB)	Spatial Working Memory (SWM)	Participants search arrays of coloured boxes, uncovering each box to locate hidden yellow tokens that must be transferred to a column on the screen’s right side.Task difficulty escalates by increasing the array size to as many as 12 boxes, demanding systematic elimination strategies. Box colours and positions are reshuffled on every trial, preventing reliance on stereotyped search patterns.
	CogState	Continuous Paired Association Learning Task (CPAL)	This task evaluates visuospatial associative memory by pairing distinct images with specific screen locations. During learning trials, each picture is shown at the centre and the participant selects - and must retain - the correct peripheral position for that picture. In later recall trials, the images reappear centrallywith hidden peripheral boxes, and the participant identifies the previously associated location, allowing accuracy to index learning and retention.
	Computerized Testof Visuospatial Working Memory (CTVWM)		Participants fixate a central cross, receive a 150 ms peripheral cue at oneof 32 positions 4.5 inches from centre, and then wait 5 or 15 seconds while monitoring geometric distractors for an occasional diamond target. When the cross reappears, they indicate the remembered cue location - or, in control trials, point to the still-visible cue - across eight trials per delay plus eight cue-present trials. Spatial precision is indexed by the mean millimetre error between indicated and true positionsfor each trial type.
	Wechsler Memory Scale – Revised/Third Edition (WMS-R/3)	Spatial Span (SS)	This task consists of two conditions. In the forward condition, participants observe the examiner tapping a sequence of blocks and must replicate the tapsin the identical order. In the backward condition, they reproduce the same sequence in the reverse order, thereby engaging higher-order spatial working-memory manipulation.
	Detection Task (DT)		Modified change-detection paradigm in which blue or red blocks, each oriented at 0°, 45°, 90° or 135°, simultaneously appear on 2 sides of fixation.On every trial participants attend to either the left or right array, encode the orientation of one target block (1T) or 4 target blocks (4T), and, after a one-second interval, press a button to indicate whether the test array matchesthe remembered orientation(s). Each set-size condition comprises 80 trials, enabling assessment of orientation-specific visual working-memory capacity.
Verbal and visual working memory
	MATRICS Consensus Cognitive Battery (MCCB)	Verbal and Visual Working Memory (WM) subdomain	This domain quantifies operational memory capacity by integrating demographically adjusted scores from two component measures: the Letter-Number Sequencing Test (LNST), which indexes verbal working memory, and the Spatial Span (SS) task, which indexes visual working memory.

Differences in working memory

Working memory was examined in 19 studies (Table 1). On simple span tasks – typically digit repetition – deficit schizophrenia patients scored lower than their non- deficit counterparts in two investigations [50, 51]; most other studies found no deficit schizophrenia versus non-deficit schizophrenia differences, but patients with the former almost always performed worse than healthy controls [52-57]. On more demanding sequencing tasks that require reordering verbal mate-rial, three studies reported poorer deficit schizophrenia performance relative to non-deficit schizophrenia [58-60], whereas three others detected no inter-patient difference [11, 61, 62]. In all investigations that included healthy controls, deficit schizophrenia patients again showed the lowest scores.

Visual working-memory outcomes varied with task complexity. On basic span tasks such as the block-tapping test, three studies detected no difference between deficit and non-deficit schizophrenia groups, although participants with the former still underperformed relative to healthy controls [62-64]. In contrast, in more demanding computerized paradigms that require identifying both shapes and their spatial locations, individuals with deficit schizophrenia scored significantly lower than both non-deficit schizophrenia patients and controls in every study that used such tasks [58, 61, 65]. The only computer task composed of two very simple conditions – remembering either the colour or the orientation of a line next to a fixation point – revealed no patient group differences [66]. In our previous study [67] on the working memory subdomain, tested with the MCCB battery, patients with deficit schizophrenia obtained lower T-scores (adjusted for demographic variables) than both their non-deficit counter-parts and healthy controls.

Overall, 5 studies (33.3%) reported greater verbal working memory deficits in deficit schizophrenia than in non-deficit schizophrenia patients, and 3 studies (37.5%) reported greater visual working memory deficits.

Differences in episodic memory and learning

Verbal memory and learning were investigated in

29 studies (Table 1). In five that used short story-recall tasks, patients with deficit schizophrenia performed comparably to those with non-deficit schizophrenia but worse than healthy controls [7, 52, 68-70]. Only one study reported poorer deficit schizophrenia performance rela-tive to non-deficit schizophrenia on this measure [59]. Likewise, in two studies that assessed verbal learning with paired- associate word lists, deficit schizophrenia and non-deficit schizophrenia groups did not differ, although both lagged behind healthy controls [7, 68].

Across multi-trial list-learning tasks (typically three to five learning trials of roughly a dozen words), ten studies reported poorer performance in deficit schizophrenia patients than in non-deficit ones, with deficit schizophrenia also lagging behind healthy controls whenever a control group was included [11, 22, 51, 58, 65, 67, 71-74]. By contrast, six investigations found no inter-patient group differences – although both patient groups performed worse than healthy controls when comparisons were available [52-55, 61, 75]. An additional experiment that employed a short three-letter word-learning paradigm likewise detected no difference between the two clinical groups but did confirm lower scores for both versus healthy controls [76].

Across the eight studies that used RBANS, five found significantly lower Immediate Memory (IM) scores – based on recall of a word list and a brief narrative – in patients with deficit schizophrenia than in those with non-deficit schizophrenia; four of these studies also included healthy controls, and deficit schizophrenia consistently scored lowest [13, 77-80]. The remaining three studies detected no patient group differences, although deficit schizophrenia participants still performed worse than healthy controls where such comparisons were available [81-83].

Visual memory was typically assessed by having participants reproduce simple patterns or complex figures after a single exposure. In most studies, deficit and non-deficit schizophrenia groups performed similarly [7, 56, 68, 70, 84]; only Horan and Blanchard [69] observed poorer deficit schizophrenia performance. Never-theless, every investigation that included healthy controls found both patient groups to be impaired relative to this control group. For recognition of abstract patterns, Bryson et al. [52] reported lower deficit schizophrenia scores than non-deficit schizophrenia, whereas Cohen et al. [7] detected no difference between the patient groups. A computerized visual memory test showed deficit schizophrenia impairments relative to both non- deficit schizophrenia and healthy controls [65], while another computer-based study found comparable performance in both clinical groups, with deficit schizophrenia still lagging behind healthy controls [61].

Across multi-trial visual-learning tasks, findings were mixed: two studies observed poorer performance in deficit than in non-deficit patients [61, 71], whereas two others detected no such difference [7, 68]. All four studies, however, reported lower scores for deficit schizophrenia patients compared with healthy controls.

In the Delayed Memory (DM) subdomain – which tests recognition of previously presented verbal and visual material – four studies found poorer performance in deficit schizophrenia patients than in those with non-deficit schizophrenia; in two of these investigations, deficit schizophrenia patients also scored lower than healthy controls [13, 77, 79, 82]. By contrast, the remaining four studies detected no difference between clinical groups, although deficit schizophrenia participants still underperformed relative to healthy controls in every case [78, 80, 81, 83].

Overall, 14 studies (48.3%) reported greater deficits in verbal episodic memory and learning in deficit schizophrenia patients than in non-deficit schizophrenia ones, and five studies (38.5%) reported greater deficits in visual episodic memory and learning.

DISCUSSION

This scoping review clarifies the state of evidence on memory and learning in deficit schizophrenia patients, who exhibit deficits in both working and episodic memory, and across verbal and visual modalities, consistently performing below healthy controls. Whether these impairments exceed those observed in non-deficit schizophrenia remains uncertain, as findings are mixed. The present synthesis underscores the clinical need for the thorough neuropsychological assessment of memory in individuals with deficit schizophrenia, and identifies gaps that future research should address.

Our findings suggest that the critical distinction in working-memory performance between the two schizophrenia phenotypes hinges on the demands placed upon the central executive system – the component that allocates cognitive resources [85]. When material is encoded and manipulated in relatively simple fashion, whether verbal or visuospatial, patients with deficit schizophrenia perform comparably to those with non-deficit schizophrenia. By contrast, tasks that impose heavier executive demands – such as re-ordering mixed sequences of digits and letters or simultaneously tracking both the identity and location of stimuli – deficit schizophrenia patients tend to reveal greater difficulty compared to their non-deficit counterparts. The evidence remains tentative, however, because few studies have employed high-load paradigms and none has systematically contrasted easy and difficult variants within the same sample. Thus, while our results align with the overall patterns reported by Bora et al. [6] and Cohen et al. [7], they extend those meta-analyses by highlighting the probable moderating role of task difficulty, a factor not explicitly examined in earlier work.

On straightforward episodic-memory tasks – such as recalling paired words or a brief narrative – patients with deficit schizophrenia do not appear to fare worse than those with non-deficit schizophrenia, nor do they differ in the reproduction of simple geometric figures. In contrast, larger group disparities emerge during learning paradigms that require the encoding of material across multiple trials. On list-learning tests and multi-trial figure-learning tasks (typically three to five trials), deficit schizophrenia patients usually score below those with non-deficit schizophrenia. The same pattern is evident when total learning scores from comprehensive batteries (e.g., the RBANS Immediate Memory index) are examined. Findings for delayed recall and recognition are less consistent: half of the RBANS studies reported lower deficit schizophrenia performance, whereas the remainder found no difference between the clinical groups. These results partially echo earlier meta-analyses [6, 7] but extend them by distinguishing among specific memory processes – initial encoding, cumulative learning, recall, and recognition – rather than treating episodic memory as a single construct.

However, drawing clear conclusions from the present evidence is difficult because, within the specific memory and learning domains analysed, most studies relied on single tasks rather than comprehensive batteries. Although some investigations used full batteries (e.g., RBANS, MCCB), these instruments are not specifically designed to assess the breadth of memory processes to the extent that the WMS does. Consequently, delineating a comprehensive profile of memory impairment in deficit schizophrenia remains a research challenge.

Current evidence is insufficient to delineate definitive moderators of memory and learning impairments in deficit schizophrenia. Notably, several studies have already linked a greater severity of negative or general psychopathological symptoms to poorer cognitive performance in deficit schizophrenia [27, 52, 61, 67, 86]. Emerging work also points to putative biological substrates of cognitive impairment in deficit schizophrenia. Structural MRI studies have highlighted anomalies in the temporal and insular cortices, hippocampal formations, and long-range white-matter tracts [25, 63, 64, 72, 81, 87]. Functional imaging reveals diminished global network integration and segregation, altered dynamic connecti-vity patterns, and aberrant cerebellar activity coupled with disrupted cerebro-cerebellar coupling [83, 88-90]. Beyond the brain, distinct gut-microbiota signatures have been reported [78], alongside immune-inflammatory dysregulation [10, 77, 80, 91-94] and altered neuro-trophic signalling [60]. Although psychopathological symptoms and putative biological markers have been suggested as salient determinants, their influence remains empirically unverified, underscoring the need for systematic investigation.

LIMITATIONS

Several limitations temper the conclusions of this review and the evidence base it summarizes. First, many studies lacked a healthy control group, making it difficult to interpret the magnitude of memory deficits in deficit schizophrenia relative to normative performance. Second, sample sizes varied widely – ranging from a handful of participants to several hundred – as did participant age and years of education, reducing comparability across studies. Third, demographic factors known to influence cognition (age, education, and sex) were inconsistently addressed: some investigations matched groups on these variables or adjusted them via ANCOVA, regression, or demographically corrected T-scores, but most did not apply any such controls. Because these variables – long recognized as fundamental moderators of memory and learning performance [30, 31] – were often untreated, residual confounding may blur true group differences. Fourth, methodological heterogeneity remains substantial: many studies employ idiosyncratic memory and learning measures that – while broadly comparable – differ in procedural details and stimulus content. Fifth, within episodic memory narrative/semantically scaffolded tasks, e.g., Logical Memory and Verbal Paired Associates, may engage strategy generation and executive scaffolding differently than less-structured list- or figure-learning tasks, which could partly account for the mixed findings across studies [95]. Consistent with Pillny et al. [16], we operationalized both tests within episodic memory; nevertheless, future work should stratify episodic tasks by semantic structure and trial complexity to examine whether differences between deficit and non-deficit schizophrenia vary with these characteristics of tasks. Although the field is beginning to adopt standardized schizophrenia batteries such as the RBANS and the MCCB, these instruments are still used in only a minority of investigations. As the literature grows, future systematic reviews and meta-analyses should be able to synthesize effect sizes so as to delineate differences in performance among deficit schizophrenia, non-deficit schizophrenia, and healthy control groups.

CLINICAL IMPLICATIONS

Beyond routine assessment, two practice-oriented steps follow from our synthesis. First, the need to incorporate tasks that explicitly manipulate complexity (e.g., single- vs. multi-trial learning, interference, immediate vs. delayed recall) and pair assessment with strategy coaching and executive scaffolding; this helps reveal deficits that simple tasks may mask and directly informs individualized goals. Second, when offering cognitive training, emphasize strategy-based encoding and retrieval practice across both verbal and visual materials, embedded in everyday activities (medication schedules, appointments, route finding). To document real-world transfer, track change using parallel forms and proximal strategy indices (e.g., semantic organization) alongside functional outcomes. In services with limited time, a brief triage screen can identify patients who warrant a memory-focused battery (preferably including WMS-type subtests or equivalents) and a tailored remediation plan.

FUTURE DIRECTIONS

Future research should investigate whether patients with deficit schizophrenia differ from those with non- deficit schizophrenia not only in retrospective memory but also in prospective memory, a domain repeatedly shown to be impaired in schizophrenia [18-21]. Memory studies would benefit from ecological paradigms that capture everyday functioning – such as remembering tasks at work or while shopping – that ideally should be implemented with immersive technologies like virtual-reality simulations [95, 97]. Longitudinal data remain sparse: only two studies have tracked cognitive change in deficit schizophrenia, and their findings are inconclusive, highlighting the need for larger, well-powered samples [55, 98]. Finally, because the severity of symptoms has been linked to cognition and may be mediated by mechanisms such as executive control and processing speed [99-101], future work should explicitly test these pathways in deficit schizophrenia.

CONCLUSIONS

Patients with deficit schizophrenia exhibit measurable impairments in memory and learning. However, the hete-rogeneity of tests and mixed results across domains and modalities preclude a definitive claim that deficit schizophrenia consistently greater difficulties than non-deficit schizophrenia in this regard. Standardized, memory- focused assessments and rigorous control of confounders are needed to enable cumulative synthesis and clearer clinical guidance.

Conflict of interest

Absent.

Financial support

Absent

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Memory and learning impairments in deficit and non-deficit schizophrenia: a scoping review

Piotr Plichta 1 , Monika Mak 1 , Jerzy Samochowiec 2 , Ernest M. Tyburski 1

INTRODUCTION

METHODS

Table 1

Search strategy and study selection

Eligibility criteria

Data extraction and quality assessment procedures

RESULTS

Study and sample characteristics

Clinical characteristics

Control of confounding variables

Measurement of memory and learning

Table 2

Differences in working memory

Differences in episodic memory and learning

DISCUSSION

LIMITATIONS

CLINICAL IMPLICATIONS

FUTURE DIRECTIONS

CONCLUSIONS

Conflict of interest

Financial support

References

Piotr Plichta

¹

,

Monika Mak

¹

,

Jerzy Samochowiec

²

,

Ernest M. Tyburski

¹