The construct (ICD‑11 shift)
ICD‑11 separates a single episode of harmful use, a harmful pattern of use, and dependence. Dependence = impaired control + increasing priority of use over other activities + physiological features (tolerance, withdrawal, neuroadaptation). Tolerance/withdrawal are supportive but not required for a use disorder — impaired control and salience are core.
Definitions you must keep distinct
- Intoxication — effects during exposure.
- Withdrawal — a substance‑specific syndrome after reduction/cessation in a neuroadapted user.
- Dependence — the longitudinal pattern of impaired control/salience.
The assessment (never "do you drink?")
Substance(s), quantity, frequency, route, time of last use (predicts withdrawal timing), escalation, craving, failed cutdown attempts, withdrawal history, consequences (health/social/legal), polydrug use, overdose history, prior treatment, and risk (suicide, driving, injecting‑related harms).
The timeline principle — the crux of dual diagnosis 🕒
Substances cause anxiety, depression, psychosis, mania, and delirium. Anchor psychiatric symptoms to the substance timeline: onset relative to use, persistence during sustained abstinence, and prior primary episodes. A stimulant user with psychosis is substance‑induced until abstinence proves otherwise — don't commit to schizophrenia at first contact.
Pitfalls
- Diagnosing a primary psychiatric disorder during active use/withdrawal.
- Missing dependence because tolerance/withdrawal are absent.
Pearls
- 🎯 Impaired control + salience define dependence; the timeline defines whether the psychiatry is primary or induced.
- 🩺 Always record time of last use — it predicts the withdrawal you're about to manage.
Next → The lens that reframes every paediatric presentation (Concept 29).