An exploratory study on the impact of medication usage patterns on relapse among community schizophrenia patients

BACKGROUND: Relapse is highly prevalent among individuals with schizophrenia, imposing a significant burden on public health systems and patients. Medication usage patterns, encompassing both prescription and usage behaviors, are critical for ensuring adherence to antipsychotic medication and controlling relapse. However, the impact of these patterns on relapse dynamics remains understudied, particularly within primary mental health care settings where data limitations such as panel-count data exist. METHODS: Data were sourced from the Basic Data Collection and Analysis System for Severe Mental Disorders in Western China, enrolling 7,137 community-based newly diagnosed schizophrenia patients under management from 2019 to 2022. The exposure factor was medication usage patterns, defined by three variables: number of drug types, drug dosage, and medication adherence behaviors. The outcome was recurrence, with readmission serving as a surrogate indicator for recurrence in this study. METHODS: Multivariate longitudinal data clustering of medication patterns was performed using Markov Chain Monte Carlo (MCMC)-based generalized linear mixed models. Adjustments were made for the minimal covariate set identified via a directed acyclic graph (DAG) constructed through systematic literature review and expert consultation, employing inverse probability weighting. The association between medication patterns and relapse was estimated semiparametrically using accelerated mean models. RESULTS: Among 7,137 schizophrenia patients, 1,633 experienced relapse, yielding a relapse rate of 22.88%. Four medication usage patterns were identified: 5067 patients (71%) belonged to the "standard treatment group," 677 patients (9.49%) to the "monotherapy group," 826 patients (11.57%) to the "inadequate treatment group," and 567 patients (7.94%) to the "overdose group." Inadequate treatment and non-standard medication practices were associated with increased relapse risk. CONCLUSION: Although most community schizophrenia patients adhere to standard medication patterns, a significant proportion receive insufficient antipsychotic treatment. Inadequate treatment and non-standard medication practices elevate relapse risk, underscoring the necessity for primary mental health institutions to implement comprehensive interventions targeting these patients. CLINICAL TRIAL NUMBER: Not applicable.