Objectives: The Wisconsin Card Sorting Test (WCST) is a complex measure of executive function that is frequently employed to investigate the schizophrenia spectrum. The successful completion of the task requires the interaction of multiple intact executive processes, including attention, inhibition, cognitive flexibility, and concept formation. Considerable cognitive heterogeneity exists among the schizophrenia spectrum population, with substantive evidence to support the existence of distinct cognitive phenotypes. The within-group performance heterogeneity of individuals with schizophrenia spectrum disorder (SSD) on the WCST has yet to be investigated. A data-driven cluster analysis was performed to characterise WCST performance heterogeneity. Methods: Hierarchical cluster analysis with k-means optimisation was employed to identify homogenous subgroups in a sample of 210 schizophrenia spectrum participants. Emergent clusters were then compared to each other and a group of 194 healthy controls (HC) on WCST performance and demographic/clinical variables. Results: Three clusters emerged and were validated via altered design iterations. Clusters were deemed to reflect a relatively intact patient subgroup, a moderately impaired patient subgroup, and a severely impaired patient subgroup. Conclusions: Considerable within-group heterogeneity exists on the WCST. Identification of subgroups of patients who exhibit homogenous performance on measures of executive functioning may assist in optimising cognitive interventions. Previous associations found using the WCST among schizophrenia spectrum participants should be reappraised. (JINS, 2019, 25, 750–760)

Major depressive disorder is a common diagnosis associated with a high burden of disease that has proven to be highly heterogeneous and unreliable. Treatments currently available demonstrate limited efficacy and effectiveness. New drug development is urgently required but is likely to be hindered by diagnostic limitations.

The importance of interview skills in psychiatry cannot be underestimated, and the acquisition of adequate interview skills must be one of the foremost aims of training. The College requirement that MRCPsych candidates must interview the patient in front of the examiners (in both parts I and II) rightly stresses the fundamental importance of interview skills in clinical practice. Maguire (1982) has questioned the adequacy of standard methods of training psychiatrists (usually reporting and discussing interview findings with a senior colleague) in interview skills. In a study of medical students, he has shown that audio/videotaped observation of interviews with feedback is superior to traditional methods (Maguire et al, 1978). Gask et al (1988) demonstrated that use of group video feedback training was effective in improving psychiatric skills in a group of general practitioners. Rutter & Cox (1981) published a series of studies examining the effects of interview style on the quality of factual information obtained and the emotional response elicited. Such work has generated interest in interview skills training and specialised courses are now run in some centres.