This course introduces Substance Use Disorders (SUDs) from a biopsychosocial perspective. Students examine the etiology of addiction by integrating biological, psychological, and contextual factors that shape the development and maintenance of substance use. The course explores prevalence and patterns of use across populations and the life course. Emphasis is placed on the effects of SUDs on individuals, families, and communities, including barriers to accessing evidence-based care. Students engage with current research on major theoretical models and apply these frameworks to case scenarios. Best practices in screening, assessment, prevention, risk reduction, treatment planning, and recovery-oriented approaches are introduced in alignment with ethical and professional standards.