Cognitive effects of six months of treatment with quetiapine in antipsychotic-naïve first-episode schizophrenia

Effects of quetiapine on cognition were assessed in a group of first-episode antipsychotic-naïve patients with schizophrenia (N = 24). A comprehensive battery of neuropsychological tests was administered at baseline and after 6 months of treatment with quetiapine. In order to examine retest effects, a matched healthy control group (N = 24) was also tested at baseline and after 6 months. Only few differential changes were observed between patients and healthy controls. Of 8 cognitive domains examined, only significant changes in executive function suggested possible ameliorating effects of quetiapine. Patients also improved on speed of processing; however, this was parallel to the retest effects found in healthy controls. When covaried for differences at baseline, patients showed smaller improvements in speed of processing than the retest effects found in controls, as well as a lack of retest effects on sustained attention and working memory that were found in healthy controls. The main result of the study is that there was very little evidence of efficacy of quetiapine on cognition. The study also indicated a lack of normal retest effects in patients compared to controls.