Antipsychotic Polypharmacy in Hospitalised Adolescents and Young Adults: Predictors, Clinical Correlates and Post‐Discharge Outcomes

Background Antipsychotic polypharmacy (APP), defined as the concurrent use of two or more antipsychotics, is common in real‐world psychiatric practice despite guidelines favouring monotherapy. While APP is linked to greater illness severity and behavioural dysregulation in adults, its correlates and outcomes in adolescents and young adults are less understood. Methods This retrospective chart review examined psychiatrically hospitalised patients under 25 prescribed at least one antipsychotic for psychosis between 2018 and 2022 at a single academic medical center ( N = 229). APP was defined as two or more antipsychotics at discharge. Sociodemographic, clinical, and treatment variables were compared between APP and monotherapy groups. Multivariable logistic regression identified independent predictors of APP, and Kaplan–Meier analysis examined time to one‐year readmission. Results APP was prescribed in 14% of patients. Compared with monotherapy, APP patients had longer hospital stays, more home medications at admission, higher long‐acting injectable (LAI) use, and greater documented history of violence. In regression, history of violence was the only independent positive predictor of APP (OR = 3.30, 95% CI [1.28–8.52]), while no LAI on discharge and positive urine drug screening were associated with lower odds. APP was not associated with higher one‐year readmission rates or shorter time to readmission. Conclusions In adolescents and young adults with psychotic disorders, APP was primarily driven by acute behavioural risk rather than illness chronicity. Despite higher clinical complexity, APP did not worsen readmission risk. When selectively applied, short‐term APP may not be associated with worse short‐term outcomes in high‐risk youth.