Substance abuse refers to the harmful or hazardous use of psychoactive substances, including alcohol, illicit drugs, and prescription medications. It often begins with occasional use or experimentation and can escalate to dependence and addiction, impacting physical and mental health. Substance abuse disrupts brain chemistry, impairing decision-making, memory, and self-control, which makes quitting without support challenging. Beyond the individual, substance abuse affects families, workplaces, and communities, contributing to strained relationships, reduced productivity, and increased healthcare costs.