Effects of four atypical antipsychotics on autonomic nervous system activity in schizophrenia

Antipsychotic drugs are associated with autonomic nervous system (ANS) dysfunction in patients with schizophrenia, but the effects of individual atypical antipsychotic drugs are not clear. This study investigated how four atypical antipsychotic drugs -risperidone, olanzapine, quetiapine, and aripiprazole- differ in their effects on ANS activity. A total of 241 Japanese patients with schizophrenia participated in this study. All of the participants received an atypical antipsychotic as monotherapy: 90 participants received risperidone, 68 olanzapine, 52 aripiprazole, and 31 quetiapine. ANS activity was assessed by means of a power spectral analysis of heart rate variability. The quetiapine group showed significantly diminished sympathetic and parasympathetic activity compared with the risperidone and aripiprazole groups and significantly lower sympathetic activity relative to olanzapine. In addition, multiple regression analysis showed that the type of antipsychotic drug significantly influenced ANS activity. We suggest that, among the antipsychotics examined-risperidone, olanzapine, quetiapine, and aripiprazole-quetiapine has the strongest effect on ANS activity.