The neurocognitive deficits is a disabling dimension of schizophrenia, with increasing recognition for psychosocial remediation approaches for this domain. WCST retraining by different instructional methods has provided variable results related to its beneficial/ generalizability effects on the other non-trained cognitive performances. The present study was intended to evaluate the efficacy of WCST retraining through the didactic retraining method on the performance of other non-trained neuropsychological tests of executive functions among patients with schizophrenia.
Methods: The present study was a randomised, double-blind controlled study conducted over 24-months among 60 patients with schizophrenia fulfilling the inclusion and the exclusion criteria. At baseline, the patients were administered with Number Back (N 1- and 2-Back) Verbal test, the Eysenck Series of Digit Span Test (ESDST), and the trail making test (TMT) to measure the baseline deficits in the various outcome measures, along with the PANSS (for illness severity) and the GAF (for global functioning). The patients were randomised equally into the control group (to receive treatment as usual ‘TAU’) or the experimental group (‘TAU’ and the intervention of WCST retraining (till they were error-free). After completing the WCST retraining, the various outcome measures were again administered to observe the changes in the different cognitive domains, the illness severity and the global functioning.
Results: Out of the 60 enrolled patients, with finally 30 patients in either group. At baseline, both the groups were homogenous with regard to the various socio-demographic, clinical, and outcome parameters. Compared to the control group in the experimental group, following WCST retraining, there was a significantly better improvement in the Hits score of N 1-Back (p=0.035), N 2-Back (p=0.045), digit forward score of ESDST (P=0.040), and the time to complete (p=0.033), and the number of errors in Set-A of TMT (p=0.029) respectively, without any significant changes in the PANSS and GAF scores. A positive correlation was found between the age of the patient and duration of education with performance on various cognitive performances including WCST parameters
Conclusions: WCST retraining of patients with schizophrenia resulted in significant improvement in the verbal working memory, attention and concentration, planning and sequencing domains of cognitive functions, but had no beneficial effect on the disease severity or global functioning.
Keywords: Schizophrenia, Cognitive deficits, WCST, N-Back test, ESDST, TMT, PANSS, GAF