Distinct prosocial behaviors associated with persistent symptom trajectories in psychiatric disorders.

Prosocial behavior, the tendency to act for others' benefit, is essential for mental health. Although social contexts strongly shape prosocial behavior in healthy individuals, its relevance across psychiatric disorders remains unclear. We examined whether context-dependent prosocial behaviors were associated with baseline psychiatric symptoms and longitudinal symptom trajectories. In a one-year longitudinal cohort study, Swedish adults (n = 4484) with at least one self-reported psychiatric disorder completed standardized questionnaires of six prosocial behavior subtypes at baseline, followed by monthly reports of alcohol use, substance use, anxiety, and depressive symptoms. Latent class linear mixed models identified longitudinal symptom trajectories, and logistic regression models investigated their associations with baseline prosocial behavior subtypes. All models adjusted for demographic covariates and shared variance across psychiatric symptom domains. Three prosocial behavior subtypes showed longitudinal associations with stable psychiatric symptom trajectory classes. Higher anonymous prosociality was associated with lower odds of belonging to the stable high alcohol use trajectory (OR = 0.89, p = 0.013). Higher public prosociality was associated with higher odds of belonging to the stable high substance use trajectory (OR = 1.15, p = 0.036). Higher emotional prosociality was associated with higher odds of belonging to the stable high anxiety trajectory (OR = 1.25, p < 0.001). No prosocial subtype was associated with depressive symptom trajectories. Overall, context-dependent prosocial behaviors were associated with persistent levels of alcohol use, substance use, and anxiety symptoms. These findings suggest that specific prosocial behaviors may refine transdiagnostic models of social dysfunction by indexing stable patterns of psychiatric symptom burden.