ABSTRACT
Objective: To determine the incidence of acute dystonic reactions (ADRs) and risk factors for ADRs in children and adolescents treated with antipsychotics. Methods: This was a retrospective chart review-based cohort study of consecutive patients who attended a university hospital's child and adolescent psychiatry department between 2015 and 2017 and who were treated with antipsychotics and had at least two follow-up visits. Results: Thirty of 441 patients (6.8%) 4-19 years of age who were treated with antipsychotics for conduct disorders (21.5%), attention-deficit/hyperactivity disorder (13.2%) and, irritability and aggression that accompanied intellectual disability (12.9%) and followed for 99.5 ± 223.3 (median: 34) days developed ADRs. ADRs developed in 11/391 patients (2.8%) treated with one antipsychotic and 19/50 patients (38.0%) treated with two antipsychotics (p < 0.001). In patients treated with one antipsychotic that developed ADRs, the time to ADRs was 4.0 ± 4.0 days after antipsychotic initiation and 2.7 ± 2.4 days after an increase in the antipsychotic dose. The time to ADRs in those treated with two antipsychotics was 3.0 ± 2.3 days after the addition of the second antipsychotic and 1.6 ± 0.8 days after a dose increase in the second antipsychotic. The incidence of ADRs during antipsychotic monotherapy was 10.5% with first-generation antipsychotics (FGAs) and 2.2% with second-generation antipsychotics (SGAs; p = 0.037). The antipsychotic was changed due to ADRs in 12/30 (40.0%) of ADR cases. Independent factors associated with ADRs were antipsychotic polypharmacy (p < 0.0001), inpatient treatment (p = 0.013), FGA use (p = 0.015), and diagnoses of schizophrenia (p = 0.039) or bipolar disorder (p < 0.0001). Conclusion: SGAs and low-potency FGA monotherapy in children and adolescents were associated with a relatively low ADR risk, whereas high- and mid-potency FGAs were associated with a high risk. Independent predictors of ADRs were antipsychotic polypharmacy, inpatient treatment, FGAs, and schizophrenia or bipolar disorder diagnoses, which may be related to more aggressive antipsychotic dosing.