Substance Use Disorder (Addiction)

Substance Use Disorder (SUD), commonly called addiction, is a treatable, chronic medical condition involving complex interactions between brain circuits, genetics, environment, and life experiences. People with SUD use substances compulsively despite harmful consequences. **Key features:** - Impaired control over substance use - Social impairment - Risky use - Pharmacological effects (tolerance, withdrawal) **Substances involved:** - Alcohol (most common) - Opioids (heroin, prescription painkillers, fentanyl) - Stimulants (cocaine, methamphetamine) - Cannabis - Benzodiazepines - Tobacco/nicotine - And others **Addiction is a brain disease:** Repeated substance use changes brain structure and function, particularly in areas involved in reward, stress, and self-control. These changes persist long after substance use stops, explaining why relapse risk remains. **Addiction is NOT:** - A moral failing or lack of willpower - A choice (initiation may be voluntary; addiction is not) - Untreatable (many evidence-based treatments exist) - Hopeless (recovery is possible and common)

Addiction develops through the interaction of biology, environment, and development: **Biological factors:** - Genetic predisposition (40-60% of risk is genetic) - Brain chemistry differences - Mental health conditions (increase vulnerability) - Some are more susceptible to substance effects **Environmental factors:** - Early exposure to substances - Peer pressure - Childhood trauma or adverse experiences - Lack of parental supervision - Availability of substances - Poverty and social conditions **Developmental factors:** - Earlier use increases addiction risk - Adolescent brain is particularly vulnerable - Critical periods during brain development **The Brain Disease Model:** Substances hijack the brain's reward system, flooding it with dopamine. Over time, the brain adapts (tolerance), and natural rewards become less pleasurable. The prefrontal cortex (decision-making) is impaired while the stress systems become hyperactive, driving compulsive use.