Substance Use and Addictive Disorders
Core concepts
Distinguish the DSM-5 substance use disorder criteria (impaired control, social impairment, risky use, pharmacological criteria like tolerance and withdrawal) - 11 criteria, severity by count (mild 2-3, moderate 4-5, severe ≥6). Understand dependence neurobiology: mesolimbic dopamine reward, kindling, and the role of GABA/glutamate in withdrawal. Know withdrawal syndromes and timelines: alcohol (tremor 6-24h, seizures 12-48h, DTs 48-96h), opioids (flu-like, piloerection, yawning), benzodiazepines (risk of seizures), stimulants (crash, dysphoria). Pharmacotherapy: naltrexone and acamprosate for alcohol; methadone/buprenorphine for opioids; nicotine replacement/varenicline. Understand harm reduction, motivational interviewing, and the stages of change model.
Traps
Tolerance and withdrawal alone do not equal dependence - they are criteria within the disorder. Alcohol withdrawal can be fatal; benzodiazepines are the treatment. Distinguish intoxication from withdrawal presentations. Opioid overdose → naloxone (short half-life, may need repeat).
Rule of thumb
Count the criteria: 2-3 mild, 4-5 moderate, ≥6 severe. Two criteria (tolerance + withdrawal) alone do not make a disorder.