Substance Use Disorders and Addictions
Core concepts
Know the DSM-5 criteria for substance use disorder (impaired control, social impairment, risky use, pharmacological criteria) and the distinction from intoxication, withdrawal, and substance-induced disorders. Recognise withdrawal syndromes: alcohol (tremor, seizures, delirium tremens), benzodiazepines, opioids, and stimulants.
Management
- Alcohol withdrawal: benzodiazepines (chlordiazepoxide or diazepam), thiamine before glucose, monitor for Wernicke–Korsakoff.
- Opioid use disorder: methadone or buprenorphine (agonist therapy) plus psychosocial support; naloxone for overdose.
- Nicotine: varenicline, NRT, bupropion.
- Stimulant use disorder: no approved pharmacotherapy; CBT and contingency management.
Traps
- Giving glucose before thiamine in a malnourished patient (risk of Wernicke's).
- Missing dual diagnosis - treat both conditions concurrently.
- Confusing tolerance and withdrawal with dependence in the older sense; DSM-5 uses a single continuum.
- Overlooking benzodiazepine co-use in opioid deaths.
Worked example
A patient with alcohol use disorder presents with confusion, ataxia, and ophthalmoplegia - Wernicke's encephalopathy, a medical emergency requiring parenteral thiamine.