The Relationship Of Serum Testosterone And Cognitive Function In Male Long-term Inpatients With Schizophrenia

Objective:Schizophrenia is a chronic and serious mental disorder prevalent in approximately 1% of the population. There are gender differences in the various dimensions of schizophrenia, including age of onset, treatment response and severity of the illness, suggesting that sex hormones may play a major role in the overall presentation of schizophrenia in individual patients. The onset of schizophrenia in males usually occurs around adolescence, which suggests a relationship between schizophrenia and increased testosterone levels. Changes in hormones have been associated with variation in symptoms in both men and women with schizophrenia. It is well established that cognitive deficits represent the core feature of schizophrenia. Hoff et al reported that there is a significant, negative relationship between serum testosterone levels and cognitive function in almost every cognitive domain (particularly verbal declarative memory) in male schizophrenia. However, Halari et al did not find any relationship between serum testosterone levels and cognition in men with schizophrenia. A recent study showed that serum testosterone levels can predict performance on verbal memory, processing speed, and working memory in men with schizophrenia. To explore the relationship of serum testosterone and cognitive function in male long-term inpatients with schizophrenia.Methods:Serum 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 (PASAT).Results:Serum testosterone levels in schizophrenic patients were similar to control subjects (P>0.05). The serum testosterone levels were largely unrelated to cognitive performance in male long-term inpatients with schizophrenia, but negative correlation with SS score(r=-230, P<0.05), positive correlation with DCT(r=-.230, P<0.05). Moreover, backward linear regression revealed that testosterone levels significantly predicted performance in DCT(β=0.240, P=0.028) and SS score(β=-0.207, P=0.047).Conclusion:The DCT and SS are widely used tests to assess spatial memory and attention function. The main findings of this study were that serum testosterone concentration correlated positively with performance in the DCT and negatively with performance in the SS score in schizophrenic patients. Moreover, after adjusting for potential confounding variables, testosterone was also associated with performance in the DCT and SS score. Spatial memory has been regarded as one of the most important cognitive functions in daily life, enabling us to locate objects in our environment or to learn a route or a path. Spatial memory and attentional deficits have been regarded as core cognitive symptoms in schizophrenia. In this study, we found that there are negative associations between serum testosterone levels with spatial memory and attention in male schizophrenia. In this study, no significant difference in testosterone levels was found between men with schizophrenia and healthy men.