Sexual dysfunction in Japanese patients with schizophrenia treated with antipsychotics

Various studies have revealed that sexual dysfunction is prevalent in schizophrenia patients treated with either first- or second-generation antipsychotics. Although sexual dysfunction may have a negative impact on adherence to treatment, no reports have studied sexual dysfunction in schizophrenia patients compared with healthy controls in Asian populations. We employed a cross-sectional, case-control survey design to collect data from 352 schizophrenic Japanese outpatients treated with antipsychotics and 367 healthy subjects. Sexual dysfunction was evaluated using the Udvalg for Kliniske Undersøgelser (UKU) Side Effect Rating Scale. The prevalence of sexual dysfunction in schizophrenic patients was 59.3% for males and 49.1% for females, while that in healthy controls was 38.0% for males and 38.4% for females. High rates of low sexual interest (37.3%), erectile dysfunction (37.3%), and problems related to ejaculation (35.6%) were found in male patients, while amenorrhea (38.7%) and low sexual interest (25.7%) were found in female patients. Significant differences were observed between cases and controls concerning the prevalence of total sexual dysfunction in males under 30 years of age (p < 0.01) and in their 40s (p < 0.01), as well as in females in their 30s (p < 0.05) and over 50 years of age (p < 0.01). When patients were divided into four monotherapy groups (risperidone, olanzapine, aripiprazole, and haloperidol), there were still no differences in any form of sexual dysfunction. The present study demonstrated a higher prevalence of sexual dysfunction in schizophrenia patients than in healthy controls. Clinicians should keep these problems in mind and discuss potential solutions with their patients in Asian populations.     

Association study between Disrupted-in-Schizophrenia-1 (DISC1) and Japanese patients with treatment-resistant schizophrenia (TRS)

Treating the 20-30% of patients with schizophrenia whose symptoms are resistant to antipsychotic treatment, a condition known as treatment-resistant schizophrenia (TRS), can be problematic. Recently, an association between Disrupted-in-Schizophrenia-1 (DISC1), a candidate susceptibility gene for schizophrenia, and TRS was reported. Associations between three missense SNPs, rs3738401 (Q264R), rs6675281 (L607F), and rs821616 (S704C) in DISC1, especially rs3738401, showed strong significance. Thus, the main aim of our current study was to examine if the reported possible functional polymorphisms in DISC1 were related to Japanese TRS. First, DISC1 was re-investigated in 485 Japanese patients with schizophrenia and 660 healthy controls with a case-control study using four candidate SNPs, rs751229, rs3738401, rs821597, and rs821616. DISC1 was not associated with schizophrenia in the Japanese population. Second, we investigated whether these SNPs contributed to TRS in 127 inpatients with schizophrenia (35 patients; TRS and 92 patients; non-TRS). The genotypic distributions of these four SNPs were not significantly different between TRS and non-TRS in either genotypic or recessive models of minor alleles. In addition, clinical variables, such as improvement in clinical symptoms, duration of hospitalization, and total antipsychotics dose amounts, were not different among the genotypes of these SNPs. Taken together, results showed that DISC1 had no apparent degree of association with Japanese patients with schizophrenia as a candidate susceptibility gene for disease per se or TRS.