Incidence and predictors of acute akathisia in severely ill patients with first-episode schizophrenia treated with aripiprazole or risperidone: secondary analysis of an observational study

Rationale: In the antipsychotic treatment of schizophrenia with little medication history, especially in drug-naïve cases, predictors of side effects are important. However, predictors of antipsychotic-induced akathisia remain unclear. Objectives: This study aimed to investigate the incidence and predictors of acute akathisia in severely ill patients with first-episode schizophrenia spectrum disorders (FES). Methods: This is a secondary analysis of our retrospective observational study. Data were obtained from 129 consecutive patients with FES involuntarily hospitalized in a tertiary psychiatric public hospital and treated with aripiprazole or risperidone. The primary outcome was the presence of acute akathisia during the first 1 month. A Cox proportional hazard model was used to examine significant predictors of the onset of akathisia. Results: Acute akathisia was diagnosed in 54 patients (42%). Neither antipsychotics (aripiprazole or risperidone), duration of untreated psychosis, iron deficiency, sex, age nor baseline symptomatic severity was identified as an independent predictor of akathisia. Rapid risperidone initiation significantly increased the onset of akathisia (adjusted hazard ratio [HR], 6.47; 95%; 95% confidence interval [CI], 1.94–21.65; p = 0.002), but rapid aripiprazole initiation did not (adjusted HR, 1.08; 95% CI, 0.50–2.31; p = 0.84). A significant interaction was found between rapid antipsychotic initiation and the risk of akathisia with aripiprazole versus risperidone (p = 0.027). Conclusions: Severely ill patients with FES initiating aripiprazole or risperidone could have a high risk for akathisia. Rapid risperidone initiation should be avoided because of the risk for akathisia, and careful monitoring of akathisia may be necessary for all patients initiating aripiprazole.