Psychological diagnosis of ADHD symptoms in adults: a review of selected diagnostic tools

Introduction

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that has its onset in childhood and whose symptoms can persist into adulthood. It is defined as clinically present symptoms of inattention and/or hyperactivity and impulsivity that can lead to impaired functioning in many areas of daily life [1].
The prevalence of ADHD in children worldwide is estimated to be between 5% and 7% [2]. According to researchers, symptoms of the disorder identified in childhood persist in 35% to as many as 70% of adults [3], and the estimated global prevalence of ADHD in adults is approximately 2.5% [4]. According to Prakash et al. [5], there has been a gradual increase in this rate in recent years (up to 5%).
During childhood, the prevalence of ADHD is higher in boys than in girls. Boys are more often diagnosed with the subtype with predominantly hyperactive behaviour, and the symptoms present often lead to learning difficulties, conduct problems, and even oppositional defiant disorder [6]. In adults, the ratio of males to females is changing (estimated at 3 : 2.9). The course of the disorder is also shifting – in adulthood, symptoms are similar in both sexes, with deficits in the attention sphere predominating [7].
The disorder has a multifaceted negative impact on the lives of those affected, both children and adults. Researchers confirm lower effectiveness of patients in the workplace, significantly lower occupational performance in this group [8], relationship problems, increased likelihood of risky behaviour [9], and psychiatric comorbidity [10]. In addition, according to the authors, this group is also at a higher risk of premature death compared to the general population [11]. Subjective quality of life is also significantly reduced in this group [12, 13]. A meta-analysis conducted by Pedersen et al. [14] also suggests lower self-esteem in adults diagnosed with ADHD (compared to a control group of healthy individuals). The cited study did not confirm gender differences in self-esteem levels in the study group [14].
On the one hand, ADHD symptoms in adults often go untreated, while on the other hand, there is a risk of overdiagnosis of the disorder. One of the reasons for this phenomenon is the lack of accurate and reliable diagnostic tools. Moreover, no single tool is available that can unequivocally confirm or exclude the presence of attention deficit hyperactivity disorder. Due to the nature of the symptoms, the diagnosis ADHD in adults is even more difficult.

Objective

Given the relevance of the issue presented, as well as the growing interest in this topic, the purpose of this article is to provide an introduction to the available scales, interviews and psychological diagnostic tools that can be applied to the diagnosis of ADHD in adults. Due to the transitional period for the introduction of a new classification of mental disorders prepared by the World Health Organization (WHO), the classification of mental disorders addressed by the diagnostic tool (DSM-IV-TR, DSM-5, DSM-5-TR, ICD-10, ICD-11) is also a criterion for selection. Since the purpose of the article is to help practicing psychologists choose appropriate diagnostic procedures, the article includes the tools that were translated into Polish.
Two independent reviewers searched the PubMed Medline database and Google Scholar. The following terms were used (in English): “ADHD”, “adults”, “diagnosis”, “DSM-IV-TR”, “DSM-5”, “DSM-5-TR”, “ICD-10” and “ICD-11”. Only peer-reviewed journals published in English or Polish were included in the analysis. The publication year of the article (years from 2004 to 2024) was also a criterion for inclusion. The resulting data was analysed to eliminate articles with different keyword meanings. Failure to meet the inclusion criterion was equivalent to exclusion from the analysis. Records were evaluated for compliance with inclusion and exclusion criteria based on an analysis of abstracts. Full articles that met the inclusion criterion were analysed in detail for their content: participants were adults, 18 years of age or older; ADHD was diagnosed based on DSM or ICD criteria; ADHD was diagnosed based on a widely used clinical or research interview, semi-structured or structured; group study including interviews, behavioural assessment scales and/or neuropsychological tests for diagnosis, screening or identification of ADHD; comparison groups – adults with diagnosed ADHD compared to control participants and/or participants diagnosed with a mental disorder; neuropsychological tests were standardized and had normative data; neuropsychological tests, behavioural assessment scales and interviews were commercially available or in the public domain.

Diagnostic criteria for ADHD according to the current classification of mental disorders

The DSM-5-TR classification uses the following term to describe the disorder in question: “Attention-Deficit/Hyperactivity Disorder” [15]. The ICD-10 Classification of Mental and Behavioural Disorders uses the name: “Hyperkinetic disorders (Disturbance of activity and attention, F90)” [16]. Its latest edition (ICD-11) provides the term: “Attention deficit hyperactivity disorder” (code: 6A05) [6]. In the DSM-5-TR and ICD-11 classifications, ADHD belongs to the group of neurodevelopmental disorders.
According to both DSM-5-TR and ICD-11, ADHD symptoms should appear before the age of 12 and be present for at least 6 months. The stated age limit is different from previous editions of the two classifications. Both older versions of the DSM and ICD classifications indicated a cut-off age for the onset of symptoms of 7 years (“Onset of the disorder no later than age 7”). The number of symptoms needed to make a diagnosis in adults also changed. For ages 17 and older, the DSM-5-TR classification now includes “at least five” symptoms for Inattention and “at least five” symptoms for Hyperactivity and Impulsivity (change from “six of nine” to “five of nine” respectively) [15].
Similar to DSM-IV-TR and ICD-10, the diagnostic criteria presented in DSM-5-TR and ICD-11 focus on childhood symptom expression, and it should be kept in mind that their diagnostic utility for adults may be limited [17]. However, both classifications highlight elements specific to patients over the age of 17 (Table 1). The symptoms of ADHD in an adult, however, can be masked by a number of compensatory strategies developed over a lifetime (e.g. note-taking, calendars, task division), which should be paid special attention to during the diagnostic process. In addition, the predominant symptoms may change with age (e.g., the excessive motor agitation observed in childhood usually manifests in an adult as feelings of inner restlessness and tension) [18].
Table 1 shows the diagnostic criteria for ADHD according to DSM-5-TR [15] and ICD-11 [6], while Table 2 lists the characteristics of the most common symptoms of ADHD in adults [1]. Diagnostic scales/ interviews based on contemporary classifications will be described later in the article.
Both DSM-5-TR and ICD-11 divide the disorder into three presentations (so-called clinical picture types): combined presentation if both criterion 1 (inattention) and criterion 2 (hyperactivity-impulsivity) are met for the past 6 months; predominantly inattentive presentation; and predominantly hyperactive/impulsive presentation. It should also be determined whether there is partial remission (“When full criteria were previously met, fewer than the full criteria have been met for the past 6 months, and the symptoms still result in impairment in social, academic, or occupational functioning”), as well as the severity of the course of the disorder (Mild: few, if any, symptoms in excess of those required to make the diagnosis are present, and symptoms result in no more than minor impairments in social or occupational functioning. Moderate: symptoms or functional impairment between “mild” and “severe” are present. Severe: many symptoms in excess of those required to make the diagnosis, or several symptoms that are particularly severe, are present, or the symptoms result in marked impairment in social or occupational functioning) [15].

Review of selected diagnostic tools

In the next part of the article, we will introduce those diagnostic tools that are worth using in the psychological diagnosis of ADHD symptoms in adults. The tools are divided into five groups: self-report scales; structured clinical interviews; tests used to assess cognitive functioning; tests/scales to assess personality structure/temperament and emotional functioning; and differential diagnosis tools. A summary of the tools listed is included in Table 3. Due to the comprehensiveness of the content presented, a selection of the tests/scales listed in Parts C, D and E will be briefly characterized.

A. Self-report scales

Adult ADHD Self-Report Scale, ASRS

The ASRS is a self-report 18-item scale for assessing ADHD symptoms in adults created by the World Health Organization (WHO) in collaboration with experts in the field. It was developed in conjunction with the revision of the WHO Composite International Diagnostic Interview (CIDI).
The subsequent questions of the scale correspond to the diagnostic criteria specified in DSM-IV-TR. They are arranged into two groups of symptoms, known as Part A and Part B [19].
The scale contains one fully structured question for each symptom from A1-A2 grouping described in DSM-IV (inattention and hyperactivity-impulsivity), as well as questions relating to 11 symptoms of deficits in higher executive functions that are not listed in DSM-IV, but which are thought to be relevant to ADHD in adults [20].
The presented scale also exists in a shortened version (Adult ADHD Self-Report Scale Screener ver. 1.1.) as a tool used in screening diagnostics. In this version, the scale consists of six questions (four items to assess attention deficit disorder, two to assess activity/impulsivity). A score of 14 points (out of 24 possible points) is considered the cutoff point [19].
The six questions, extracted from the full version of the scale using stepwise logistic regression to optimize consistency with clinical classification, were found to be the most predictive of ADHD symptoms in adults [19, 21, 22]. However, the literature emphasizes that the shortened version of the ASRS scale is only used for screening purposes and should not be considered a diagnostic test. It is therefore imperative that cases exceeding the threshold undergo further detailed functional and symptomatic evaluation [19].
In 2017, the ASRS scale was adapted to the latest fifth edition of the DSM [23]. These versions reduce the number of required symptoms and increase the required age of onset of the first symptoms of the disease (to 12 years of age). The use of an earlier version of the scale results in under-identification of those affected by ADHD [24]. In addition, in their analysis, Pettersson et al. [25] estimated the scale’s sensitivity at 92% and specificity at only 27%.
For more information on the scale, visit the National Comorbidity Survey (NCS) website at https://www.hcp.med.harvard.edu/ncs/asrs.php.

The Wender Utah Rating Scale (WURS)

Like the tool described above, the WURS self-report scale assesses childhood symptoms and behaviours consistent with ADHD that continue into adulthood [26]. It was created in 1993 [27]. The scale enables a detailed retrospective assessment of childhood functioning (including an assessment of the emotional sphere). Its undoubted advantage is the identification of a threshold value that suggests that symptoms of ADHD were present in childhood [28].
The scale is available in both a full version (originally 61 items, now 60) and a 25-item shortened version (WURS-25) [28]. The full version allows diagnosis of five areas: disruptive mood/behaviour, ADHD, anxiety/dysphoria, social problems, and academic problems [27, 29]. In the literature, we can also find a 45-item version of the scale [30] and an 8-item version [31].
According to Gift et al. [28], the full version of the scale is a more sensitive test in terms of differentiating between adults with ADHD symptoms and patients with generalized anxiety disorder and a diagnosis of a depressive episode, while the shortened version more accurately diagnoses those with ADHD, separating them from those without symptoms.

Conners’ Adult ADHD Rating Scales (CAARS)

According to Marshall et al. [32], the Conners’ scale should be the recommended scale for diagnosing symptoms of ADHD (in conjunction with a structured clinical interview). It consists of more than just the 18 DSM symptoms. Its specificity rates assessed in young adults are also satisfactory. The tool is the only scale that has control questions to reveal false-positive answers. However, a meta-analysis conducted by Smyth and Meier [33] revealed significantly weaker internal consistency for the part of the test assessing hyperactivity/impulsivity symptoms for female diagnoses.
In a comparative study they conducted, Kwan et al. [34] set the cutoff point for the full version of the scale for the total score at < 44 points, and < 54 points for the subscale assessing the presence of ADHD with predominantly inattentive presentation. When the accuracy of the analyses carried out improved, the values given increased to < 54 points and < 63 points, respectively. At the same time, the cited authors point out that this result is an unsatisfactory predictor of a false-negative diagnosis. A similar result was also obtained in their own study by Harrison et al. [35].
Alexander and Liljequist [36] showed no greater diagnostic accuracy of the Conners’ Adult ADHD Rating Scale-Self-Report: Long Format (CAARS-S:L) compared to the Conners’ Adult ADHD Rating Scale-Observer Report: Long Format (CAARS-O:L).

B. Structured clinical interviews

Adult ADHD Clinical Diagnostic Scale (ACDS)

Phase one of this interview includes a retrospective assessment of the symptoms of childhood ADHD. The second phase evaluates symptoms present in the 6 months before the day of the survey. This assessment includes all nine DSM-IV Criterion A symptoms for inattention and nine symptoms of hyperactivity/impulsivity. In addition, 14 symptoms outside the DSM that are considered relevant to adult ADHD (including difficulties with planning and organization, emotional lability) are assessed. Most of the additional items are consistent with the WURS scale described above [20, 37].

Structured Clinical Interview for the DSM (SCID-5)

This interview was created by First et al. [38]. The version of the scale presented here has been expanded to include a module that allows symptoms of ADHD in adults to be assessed (Module K – Externalizing Disorders). In addition to symptoms of ADHD in adults, this module also covers periodic explosive disorder and gambling disorder/pathological gambling. The assessment of the presence of symptoms encompasses the last 6 months before the date of the study for ADHD in adults, and 12 months for the other two disorders. In a study by Gorlin et al. [39], satisfactory reliability and accuracy of the interview was demonstrated. The module had high internal consistency and correlated strongly with commonly used scales for assessing symptoms of ADHD in adults.

Conners’ Adult ADHD Diagnostic Interview (CAADID)

CAADID is a semi-structured mixed interview consisting of two parts. Part one collects information from the following areas: demographic history, psychomotor development, ADHD risk factors, and comorbidity. Part two assesses the patient’s condition in conjunction with the DSM-IV symptoms of ADHD. The first part can be filled out by the patient alone; the second part should be performed by a clinician familiar with the diagnostic criteria of attention deficit hyperactivity disorder [40]. A study by Epstein and Kollins [41] confirmed the satisfactory psychometric indicators of this tool.
The version of the test available in Poland (CONNERS 3, Questionnaire Set for the Diagnosis of ADHD and Comorbidity), based on DSM 5 guidelines, allows for the diagnosis of children and adolescents between the ages of 6 and 18 [42]. The test can be used both for screening and for preparing treatment recommendations. It can also be utilized by people without psychological training (teachers, psychiatric doctors, nurses, educators). However, it is important to keep in mind that this tool only allows the probability of ADHD in the subjects to be determined.

Diagnostic Interview for ADHD in Adults (DIVA-5)

The DIVA-5 structured interview is one of the most well-known tools used by specialists in Poland when diagnosing symptoms of attention deficit hyperactivity disorder. The current third edition is adapted to the DSM-5 diagnostic criteria [43].
Pettersson et al. [25] demonstrated 90% sensitivity and 73% specificity of the DIVA-5 scale in a group of adult outpatients presenting for ADHD evaluation. Similar values for validating the Korean version of the scale were obtained by Hong et al. [44], diagnostic accuracy was estimated at 92%, sensitivity at 91.30%, and specificity at 93.62%. However, at the same time, in the conclusion of the paper the authors state that significant clinical and demographic differences were found in the study groups (ADHD group – control group), which may be a serious limitation of the research conducted.

C. Selected tools for assessing cognitive functioning

Marshall et al. [32] recommend performing a battery of tests to assess various aspects of subjects’ cognitive functioning rather than tests that assess individual cognitive functions. This recommendation is dictated by the significant variability in the level of performance of individual tasks depending on the duration of the test (patients can effectively focus their attention on specific content for a short time). In addition, the symptoms of ADHD are most likely overlapping multiple cognitive deficits of moderate severity, none of which are necessary or sufficient for a diagnosis of the disorder [32]. Unfortunately, the diagnostic batteries recommended by the authors do not have a Polish translation and Polish adaptation.
Of the difficulties in the cognitive sphere, reduced efficiency of attention processes and executive function deficits are most characteristic of people with ADHD symptoms [9]. In the case of ADHD, they persist from childhood and are pronounced in adulthood [45], including in people whose other core symptoms of the disorder have significantly quieted in older age [46]. Executive function deficits are considered the primary cause of dysfunction in various areas of life for adults diagnosed with ADHD [47]. Difficulties centre around planning, working memory, and response inhibition [48, 49].
The tests recommended by the aforementioned authors [32], and available in Poland to assess individual cognitive functions, include the tools listed in Table 3 (with particular emphasis on the tests that assess the efficiency of attention processes and the efficiency of so-called frontal functions – executive functions and working memory).

D. Selected tools for assessing personality structure and emotional functioning

Research in recent years indicates that important, and previously underappreciated, symptoms of ADHD include difficulties in processing emotional information [50] and in adequate emotional regulation [51]. These deficits largely explain the impact of ADHD on the education, social and professional lives of those affected [52, 53].
A meta-analysis conducted by Soler-Gutiérrez et al. [54] revealed that adults with ADHD are significantly more likely to use maladaptive emotion regulation strategies compared to those without any symptoms. In addition, emotional dysregulation is associated with increased symptoms, poorer executive function, increased risk of comorbidity, interpersonal conflicts and conflicts with the law. According to Shaw et al. [55], the percentage of adults with ADHD who have difficulties in the area in question can be as high as 70%, with negative consequences that exceed those of hyperactivity [56].
Krieger et al. [48], on the other hand, report that scores on scales assessing negative emotionality and so-called surgency (talkative, energetic, assertive) are characteristic of people with ADHD.
Young Schema Questionnaire (YSQ-S3-PL) is noteworthy among the commonly used diagnostic tools. The Polish adaptation was prepared by Oettingen et al. [57]. This questionnaire is a fairly new tool and was created to assess the severity of early maladaptive schemas according to J. Young’s concept, and is not directly used to assess the presence of ADHD symptoms in adults. However, there are emerging scientific reports indicating that schemas in the domains of Impaired Limits (Insufficient Self-Control/Self-Discipline [58]), Disconnection and Rejection (Defectiveness/Shame [59], Social Isolation [58]), Impaired Autonomy and Performance (Failure [58]), Other-Directedness (Subjugation [59]), Overvigilance and Inhibition (Emotional Inhibition [58]) are characteristic of adult patients with symptoms of ADHD.

E. Differential diagnosis

A complete diagnosis of an adult with suspected ADHD should also include an evaluation of comorbid psychiatric disorders and somatic conditions. Lack of diagnosis during childhood and the resulting school and relationship difficulties often contribute to secondary symptoms of depressive and anxiety disorders.
In a study by Schein et al. [60] (n = 337,034), the mental disorders significantly more frequently diagnosed in adults with ADHD symptoms included (values for adults respectively with and without an ADHD diagnosis are given in parentheses): anxiety disorders (34.4% and 11.1%, respectively), depressive disorders (27.9% and 7.8%), sleep/vigilance disorders (13.2% and 7.7%), trauma- and stress-related disorders (12.4% and 3.4%), and substance- and addiction-related disorders (9.4% and 5.0%).
Among personality disorders, dependent personality traits are significantly more frequently diagnosed in adults diagnosed with ADHD than in the general population [61]. When ADHD subtypes were analysed, symptoms of ADHD with predominantly inattentive presentation were more often associated with the mentioned personality trait, while the combined subtype was more often accompanied by antisocial and passive-aggressive personality traits [61].
The literature is also increasingly paying attention to the sleep disorders that accompany ADHD symptoms in adults [62]. They have been observed since childhood [63], and are significantly more troublesome in the combined presentation of ADHD and in patients with a severe course of the disorder [64]. Adequate therapeutic and pharmacological care of this sphere of patient functioning can significantly reduce the symptoms [65].
Table 4 shows the diagnoses from the DSM-5 and ICD-11 classifications that should be considered when making a diagnosis of ADHD [6, 66]. Among the tools listed in Table 3, the following are noteworthy at this point: The Borderline Personality Disorder checklist (BPD checklist) and the Personality Inventory for ICD-11 (PiCD).
The BPD checklist is a DSM-IV-based self-report questionnaire designed to measure the intensity of complaints experienced in relation to certain borderline personality symptoms over the past month. The scale consists of 47 items, formulated on the basis of the BPD criteria according to DSM-IV, literature describing the manifestations of borderline personality, and clinical observations. The translated scale can be found in the article by Bloo et al. [67].
The PiCD is a 60-item questionnaire designed to measure the five dysfunctional trait domains of personality disorders included in the ICD-11 classification [68]. The inventory has adequate reliability, structural and differential validity, and convergent validity with respect to the Big Five model, i.e. the five dysfunctional trait domains from the DSM-5 Alternative Model for Personality Disorders, and other models of personality pathology [69]. The Polish adaptation of the scale was prepared by Cieciuch et al. [69].

Summary

An accurate psychological diagnosis of attention deficit hyperactivity disorder is not an easy task. It requires not only specialized knowledge based on the latest classifications of disorders, but also the expertise and ability to adequately apply a range of diagnostic tools that allow a holistic assessment of the subject’s functioning (not just cognitive). As the presented literature review shows, we also do not have diagnostic tools to make a confident diagnosis of attention deficit hyperactivity disorder. Ongoing research only indicates that the disorder is more or less likely to be present. Therefore, a holistic psychological diagnosis that includes the areas of patients’ mental functioning covered in this paper seems to be a necessity. Relying only on a single screening scale or diagnostic interview in the diagnostic process is fraught with the risk of false-positive or false-negative results.
It needs to be emphasized that this review of the available tools should not be considered an algorithm for diagnostic management. It is intended to assist in the selection of appropriate treatment procedures, and each psychologist/diagnostician can be as flexible as possible in the choice made. The only recommendation may be to use the tools that cover all of the five areas of diagnosis.

Funding

No external funding.

Ethical approval

Not applicable.

Conflict of interest

The authors declare no conflict of interest.

References