This study examines long-term mortality patterns and contributing factors among individuals with first-episode psychosis (FEP) using a 25-year population-based cohort from Hong Kong. The study provides new insights into how mortality risks change and how clinical, social, and treatment-related factors influence mortality over a 25-year follow-up, which emphasizes the need for stage-specific strategies that integrate physical and mental health care to improve long-term outcomes for people with psychosis.