Substance intoxication, withdrawal and use disorders in youth — branching viva

Opening

Examiner: A 16-year-old is in your clinic with daily cannabis use since age 13, falling school marks, a new and risky peer group, and a CRAFFT screen positive on five items. His parents have read that cannabis causes psychosis and are frightened. How do you frame this assessment? [3]

Candidate: I would treat this as a likely cannabis use disorder within an SBIRT framework. I would take a structured, confidential, multi-informant history — the young person alone for the substance, risk and mental-health history — screen and confirm the diagnosis on DSM-5 criteria, assess mental state and suicide risk, and only then move to a stepped-care plan. I separate three things at every encounter: intoxication, withdrawal and the use disorder. [3]

Branch 1 — diagnosis

Examiner: What DSM-5 criteria make this a use disorder rather than experimentation? [1]

Candidate: A substance use disorder is two or more of eleven criteria in twelve months, drawn from four clusters. He has impaired control (failed efforts to cut down), social impairment (school decline, withdrawal from sport, risky peer group), risky use (driving after using), and pharmacological change (tolerance and a withdrawal syndrome). He meets multiple criteria, so this is at least a moderate disorder — experimentation would not meet the criteria at all. [1]

Examiner (probe): Why not just rely on a urine drug screen? [3]

Candidate: A urine drug screen detects recent exposure to a class of drug; it does not diagnose a use disorder, does not measure impairment, and has false positives and negatives. The diagnosis is clinical, made on criteria from the history. A screen used without consent as surveillance also destroys the therapeutic alliance. [3]

Branch 2 — screening and assessment

Examiner: How do you screen, and what does a positive CRAFFT mean? [2]

Candidate: I screen every adolescent with CRAFFT — car, relax, alone, forget, friends, alcohol-and-drugs — which asks about the consequences of use rather than the amount. Two or more positive items signals a likely problem and the need for a full structured interview; he scores five. I could also use S2BI, which stratifies by past-year frequency. I confirm with a HEEADSSS-framed interview covering every substance, route, frequency, consequences, mental state, self-harm, safeguarding and pregnancy. [2] [3]

Branch 3 — the cannabis-psychosis question

Examiner: The parents are frightened about psychosis. What do you tell them? [6]

Candidate: I explain the honest evidence: the Moore systematic review found a dose-response relationship between earlier and heavier cannabis use and later psychotic outcomes, and the risk is greatest with high-potency, early-onset use in a vulnerable young person. The relationship is not deterministic — most users do not develop psychosis — but it is real and clinically actionable. I counsel on reducing use and monitor his mental state, and I explain that persistent psychotic symptoms after a documented washout period would point to a primary disorder needing urgent mental-health care. [6]

Branch 4 — treatment

Examiner: What is your stepped-care plan? [4]

Candidate: His severity warrants specialist youth alcohol-and-other-drug input. First-line is evidence-based psychosocial therapy — motivational interviewing, cognitive behavioural therapy, family-based therapy and contingency management. The Cannabis Youth Treatment study established that brief, manualised interventions reduce cannabis use in adolescents, and the Waldron review confirmed these as the treatments with the strongest evidence. I address his cannabis withdrawal with sleep, mood and craving management, treat the comorbid low mood actively, and build a relapse-prevention plan with a clearly named clinician. [4] [5]

Examiner (probe): What if this were an opioid use disorder instead? [7]

Candidate: I would confirm the diagnosis after medical stabilisation and offer buprenorphine within a specialist framework, alongside psychosocial therapy. The Marsch trial showed that a longer buprenorphine taper outperformed short detoxification in opioid-dependent adolescents and young adults. I would provide take-home naloxone and overdose-prevention education throughout, because overdose death is the feared complication. [7]

Branch 5 — the corners

Examiner (final corner): He relapses after three months of improvement. What is your framing? [3]

Candidate: I frame substance use disorder as a chronic, relapsing condition with a non-linear recovery trajectory, so relapse is part of the course for many and not a personal failure. I review the triggers — cue conditioning by people, places and paraphernalia is powerful — strengthen the relapse-prevention plan, re-engage him in the therapy that worked, and keep the therapeutic alliance and the named clinician in place. Engagement and low-barrier follow-up are themselves treatment. [3]