Relationship of serum testosterone levels with cognitive function in chronic antipsychotic-treated male patients with schizophrenia

IntroductionSome evidence suggests that testosterone might be involved in the cognitive impairments of schizophrenia. We assessed major cognitive domains and serum testosterone levels in male long-term inpatients with schizophrenia. This study aimed to test whether testosterone in serum was abnormal in patients, and whether it was related to the cognitive impairment of schizophrenia. MethodsSerum testosterone levels in male schizophrenics (n=80) and normal controls (n=40) were measured by immunoassay. All patients were assessed for performance on executive functions, sustaining and focusing of attention, memory functions, and verbal fluency using the Digit Cancellation Test (DCT), Semantic Fluency Test, Spatial Span (SS), Trail Making Test, part A (TMT-A), Block Design, and Paced Auditory Serial Addition Test. ResultsSerum testosterone levels in schizophrenic patients were similar to control subjects (P>0.05). We found that serum testosterone levels were significantly correlated with total time taken (in seconds) in the DCT (r=0.261, P<0.05) and SS score (r=-0.240, P<0.05) in schizophrenic patients. Moreover, backward linear regression revealed that testosterone levels significantly predicted performance in DCT (=0.240, P=0.028) and SS score (=-0.207, P=0.047) in patients. DiscussionOur findings suggest that there is no significant difference in serum testosterone levels between groups, and that serum testosterone levels are associated with the spatial memory and attention deficits in chronic antipsychotic-treated male patients with schizophrenia.