Correlation Between Intellectual Function and Relapse of Schizophrenia Regarding Dose Reduction in Patients Undergoing High-Dose Antipsychotic Therapy

Abstract

Background: Influence of dopamine (DA) on working memory (WM) performance follows an inverted U-shaped function, with excessive levels of neurotransmitters impairing WM performance. Antipsychotics have an ameliorating effect on this impairment according to studies on monkeys and rats. DA release increases during illness exacerbation in schizophrenia. Therefore, WM performance may improve by increased DA release in patients with schizophrenia being treated with high-dose antipsychotics. If improvement in WM performance was an indicator for increased DA release, it could serve as a predictor for relapse.

Method: We included 130 patients with schizophrenia taking ≥1,000 mg chlorpromazine equivalent/day. The antipsychotic dose was reduced to ≤1,000 mg/day. The Digit Span, Vocabulary, and Block Design tests were used before the dose reduction and in comparing relapse and non-relapse cases.

Results: 51 subjects relapsed. In comparison with the no relapse group, the relapse group scored significantly higher in the Digit Span test but significantly lower in the Vocabulary and Block Design tests. The logistic regression analysis indicated a correlation between relapse and cognitive function.

Conclusion: Our study revealed a correlation between relapse and cognitive function. Our findings are consistent with the idea that relapse and changes in cognitive function are caused by increased DA release.