The chapter examines the intersection of clinical and legal systems in managing serious mental illness (SMI), focusing on mental health crises, relapse, commitment criteria, guardianship, and decision-making capacity. Mental health crises are defined as acute episodes of psychological distress requiring immediate intervention, often triggered by stress, trauma, or psychiatric instability. Relapses are framed as the recurrence of symptoms after a period of improvement, with significant implications for functioning and care continuity. The chapter outlines criteria for involuntary commitment, emphasizing risk to self or others and grave disability, and explores legal guardianship and capacity assessments, distinguishing between informed consent and assent. Psychiatric advance directives (PADs) are highlighted as tools to preserve autonomy. Prevalence data underscore the systemic burden of SMI-related crises and confinement. Strategies include behavioral planning, reinforcement-based interventions, and collaborative care models that integrate clinical insight with legal safeguards to support autonomy, safety, and recovery.