SubstanceUse

Substance use refers to the consumption of psychoactive substances, including alcohol, nicotine, cannabis, opioids, stimulants, sedatives, hallucinogens, and prescription medications used nonmedically. It ranges from casual or social use to problematic use and substance use disorders.

Problematic use arises when it harms health, safety, relationships, or daily functioning. A substance use disorder is a medical condition marked by impaired control, cravings, tolerance, withdrawal, and continued use despite negative consequences. Distinctions are made among use, misuse, and disorder based on clinical criteria and functional impact.

Prevalence and risk factors vary by substance and context. Risk factors include genetics, mental health conditions, trauma, poverty, age, peer influence, and access to substances and care. Social and cultural factors shape patterns of use and responses to treatment.

Health and social harms can be significant. Substance use contributes to acute risks such as accidents and overdoses, as well as chronic disease, mental health disorders, infectious disease transmission, and social disruption. Stigma and discrimination can hinder help-seeking.

Prevention and treatment rely on multiple strategies. Evidence-based treatments include pharmacological options (for opioid use disorder, methadone or buprenorphine; for alcohol, naltrexone or acamprosate), and behavioral therapies (cognitive-behavioral therapy, motivational interviewing). Harm reduction, such as naloxone distribution and sterile syringe programs, reduces risk. Recovery support and coordinated care improve outcomes.

Policy and public health focus on expanding access to care, implementing proven guidelines, reducing stigma, and monitoring trends with surveillance systems.