Categorical diagnosis vs. dimensional approach in psychiatry: implications for pharmacotherapy

Contemporary psychiatry relies primarily on categorical classification systems such as DSM and ICD, which serve important organizational and communicative functions but provide limited guidance for rational pharmacotherapy. Growing empirical evidence indicates that psychopathology is largely dimensional and heterogeneous, and that the mechanisms underlying psychiatric symptoms often cut across traditional diagnostic boundaries. This article discusses key limitations of categorical diagnosis and presents dimensional approaches – particularly the RDoC and HiTOP frameworks – as alternative models that better capture symptom continuity, comorbidity, and clinical heterogeneity. Using depression and anxiety disorders as illustrative examples, neurobiological and clinical data are reviewed that demonstrate distinct functional profiles and differential treatment responses within the same diagnostic categories. Integrating dimensional models with the concept of drug-centred psychopharmacotherapy and with affective neuroscience leads to the conclusion that therapeutic targets defined in terms of dimensions of mental functioning provide a more precise and clinically useful basis for pharmacological treatment than categorical diagnoses alone.