Smoking as predictor of relapse at 3 years following first-episode psychosis: a retrospective cohort study in Hong Kong

Abstract

OBJECTIVE: Relapses in psychosis are costly and may have irreversible consequences. Relapse prevention is therefore one of the most important and challenging targets in the treatment of psychotic disorder. Medication non-adherence is at present the only consistent relapse predictor with high predictive power. However, other consistent predictors have not been identified due to limitations in previous studies. We aim to investigate relapse predictors in a large cohort of patients with first-episode psychosis. METHOD: This is a retrospective cohort study designed to evaluate relapses in first-episode psychosis patients in 3 years. A total of 1400 patients ’ case records were retrieved from a hospital database. Potential relapse predictors including demographic variables, baseline clinical measures, medication adherence, and residual positive symptoms upon clinical stabilization were collected. RESULTS: The cumulative relapse rates were 19.3% by year 1, 38.4% by year 2, and 48.1% by year 3. Multivariate Cox-proportional hazards regression analysis revealed that medication non-adherence, smoking, schizophrenia diagnosis, younger age, and shorter baseline hospitalization were associated with an increased risk of relapse in 3 years. CONCLUSIONS: Nearly half of patients relapsed after 3 years following their fi rst-episode psychosis. Smoking as a predictor of relapse is an intriguing new finding supportive of a link between nicotinic receptors and the dopamine system. Their relationship deserves further investigations with potential clinical implications for relapse prevention.