Substance Use Disorders



Any pattern of substance use causing significant physical, mental, or social dysfunction

  • Substances of abuse include:
    • Alcohol
    • Cannabis (marijuana, hashish, cannabis oil, extracts); also sold as highly concentrated extracts for use in vaporizers
    • “Club drugs” (MDMA [ecstasy, Molly], PMMA [Superman], flunitrazepam, γ-hydroxybutyrate [GHB])
    • Dissociative drugs (ketamine, phencyclidine [PCP], tenocyclidine [TCP])
    • Hallucinogens (lysergic acid diethylamide [LSD], salvia, ayahuasca, N, N-dimethyltryptamine [DMT])
    • Inhalants (glue, paint thinners, nitrous oxide)
    • Opioids (carfentanil and other synthetic analogs of fentanyl, heroin, kratom, desomorphine [Krokodil], U-47700 [Pink])
    • Prescription medications
      • CNS depressants (barbiturates, benzodiazepines, hypnotics)
      • Dextromethorphan (“Robotripping”)
      • Opioids and morphine derivatives (fentanyl, hydrocodone, oxycodone, others)
      • Stimulants (amphetamines, methylphenidate)
    • Stimulants (cocaine, amphetamines, methamphetamines, khat)
    • Synthetic cannabinoids (Spice, K2, fake weed); often much more potent than marijuana; may be smoked or vaporized
    • Synthetic cathinones (bath salts, alpha-PVP [Flakka])
    • Tobacco



  • Predominant age: 18 to 25 years
  • Predominant sex: male


  • 59.3 million Americans (21.4%) reported illicit drug use in the past year in 2020.
  • 13.8% of 12- to 17-year-olds; 37.0% of 18- to 25-year-olds
  • 1 in 3 (34.5%) young adults used marijuana in the past year.
  • Opioid overdose is the leading cause of death for persons 26 to 38 years of age in the United States. More than 80% of these are due to synthetic opioids.
  • Many states require naloxone to be prescribed or offered when issuing a prescription of opioids to patients at increased risk of overdose, such as those receiving ≥50 morphine milligram equivalents per day of an opioid, those taking both opioids and benzodiazepines, and those with a history of substance abuse.

Etiology and Pathophysiology

Substances of abuse affect dopamine and other neurotransmitter receptors. Variant alleles may account for differences in susceptibility to misuse of different substances.

Risk Factors

  • Academic problems, school dropout
  • Criminal involvement
  • Depression, anxiety
  • Family dysfunction or trauma
  • Family history
  • Peer or family use or approval
  • Unemployment, low socioeconomic status

General Prevention

  • Early identification and aggressive early intervention improve outcomes.
  • Universal school-based interventions are modestly effective for prevention.

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