High-Risk Periods and Opportunity Windows in First-Episode Psychosis, Cannabis Use, and Suicide Risk: A Narrative Systematic Review

First-episode psychosis (FEP) represents a significant vulnerability period for suicidal behavior, particularly among cannabis users. This systematic review examines high-risk periods and intervention windows for this population. Following PRISMA guidelines, we analyzed studies from 1990 to 2025 focusing on temporal patterns of suicide risk, cannabis use dynamics, and intervention timing in FEP. Results identified several distinct high-risk periods: pre-treatment untreated psychosis, the first month after treatment initiation, post-discharge transitions, and periods of cannabis use pattern changes. Key intervention opportunity windows include symptom stabilization periods, moments of heightened insight, and service-level transitions. Intervention timing significantly impacts effectiveness, with early interventions (within the first month post-FEP onset) demonstrating superior outcomes. This review establishes a temporal risk framework for understanding dynamic suicide risk patterns in cannabis-using FEP patients and provides evidence-based recommendations for optimizing intervention timing to reduce both cannabis use and suicidal behavior during critical vulnerability periods.