Objectives: Catecholamines, brain-derived neurotrophic factor (BDNF) and cytokines may be involved in the pathophysiology of schizophrenia. The aim of this study was to examine the associations between serum BDNF levels, plasma catecholamine metablolites, cytokines and the cognitive functions of patients with schizophrenia treated with atypical antipsychotic monotherapy. Methods: One hundred and forty-six patients with schizophrenia and 51 age- and sex-matched healthy controls were examined for peripheral biological markers and neurocognitive test. Results: There were positive correlations between serum BDNF levels and scores for verbal memory and attention and processing speed as well as between serum BDNF levels and negative symptoms. Furthermore, there was a negative correlation between the plasma homovanillic acid (HVA) level and motor function and a positive correlation between the plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) level and attention and processing speed. There were no significant correlations between interleukin-6 or tumour necrosis factor alpha and cognitive function. Moreover, there were no significant correlations between the plasma levels of HVA, MHPG, cytokines and clinical symptoms. Conclusions: Serum BDNF levels are positively related to the impairment of verbal memory and attention, plasma HVA levels are positively related to motor function, and plasma MHPG levels are positively related to attention in patients with schizophrenia.

Background: This study aims to determine the effectiveness of blonanserin (BNS) on the cognitive and social functions of patients with schizophrenia compared with risperidone (RIS) during acute-phase (8-week) treatment. Methods: A total of 39 schizophrenia inpatients were included in this study. The subjects received either BNS (N=20) or RIS (N=19), and the clinical responses were evaluated periodically. The concomitant use of mood stabilizers was not allowed. Efficacy was assessed with the Positive and Negative Syndrome Scale for schizophrenia. Cognition was assessed using the Brief Assessment of Cognition in Schizophrenia, Japanese-language version. Social function was assessed using the Life Assessment Scale for the Mentally Ill. Results: For both groups, each assessment exhibited a decrease in the mean change from baseline on the Positive and Negative Syndrome Scale. The depression subscale was significantly improved in the BNS group compared with the RIS group at 8 weeks after administration. BNS improved verbal fluency and executive function (cognitive function) and daily living and work skills (social function). Compared with the RIS group, BNS was observed to improve daily living. Conclusion: BNS may improve psychotic symptoms, cognitive function, and daily living in patients with acute-phase schizophrenia. BNS may be superior to RIS in the improvement of daily living.

In the present study, we examined the effects of olanzapine on plasma levels of catecholamine metabolites, brain-derived neurotrophic factor, and cytokines (interleukin-2, interleukin-6 and tumor necrosis factor-alpha) using 32 olanzapine-treated schizophrenic patients and age and sex-matched 55 healthy individuals. Treatment with olanzapine for 8 weeks improved both positive and negative symptoms of schizophrenia. It also increased the plasma 3-methoxy-4-hydroxyphenylglycol levels, which were associated with the changes in the total scores of negative symptoms measured on the Positive and Negative Symptom Scale, and decreased the plasma homovanillic acid levels. In addition, treatment with olanzapine for 8 weeks reduced the plasma interleukin-2 levels. In contrast, olanzapine did not alter the plasma levels of brain-derived neurotrophic factor, interleukin-6, or tumor necrosis factor-alpha. These results suggest that olanzapine influences the dynamics of catecholamine and interleukin-2, which might be associated with its clinical efficacy.