CARN-AP common mistakes
CARN-AP · Understand the traps and how to avoid them.
Documenting a substance use disorder diagnosis (and coding it) on the basis of a positive screening score alone - e.g., a patient scores 5 on AUDIT-C or answers 'yes' to two CRAFFT items and the candidate marks 'alcohol use disorder confirmed.'
Screening instruments are designed to detect probable risk, and candidates under time pressure conflate 'positive screen' with 'diagnosis,' especially when the instrument's name sounds diagnostic.
What to do instead
State the rule explicitly in your notes: a screen triggers a brief assessment, and diagnosis requires DSM-5-TR criteria (≥2 of 11 in 12 months) plus rule-outs. When a stem asks 'what is the next step,' the answer is a structured diagnostic interview, not a diagnosis or immediate treatment placement.
Attributing depressive, anxious, psychotic, or cognitive symptoms to intoxication/withdrawal without any planned reassessment - e.g., starting an antidepressant on hospital day 1 in a patient in alcohol withdrawal, or conversely dismissing a first-break psychosis as 'just meth.'
Acute intoxication and withdrawal mimic psychiatric syndromes, and the emergent medical picture dominates attention. Candidates also fear 'undertreating' and act rather than wait.
What to do instead
Use the diagnostic overshadowing rule: defer primary psychiatric diagnosis until 2–4 weeks of sustained abstinence (longer for stimulants/cannabis), treat acute safety issues now, and reassess with validated tools (PHQ-9, GAD-7, PCL-5) at follow-up. Choose 'reassess after a period of abstinence' over 'begin psychotropic now' when the stem involves active use.
Recommending a level of care based on patient preference, insurance, or a single severity indicator (e.g., 'patient prefers outpatient,' or 'lives alone so inpatient') rather than completing a multidimensional assessment - placing a patient with a CIWA score of 15 or a history of complicated withdrawal into outpatient detox.
Candidates memorize levels of care as a list and skip the six ASAM dimensions; the distractors are written to sound compassionate or practical.
What to do instead
For every placement item, run the six dimensions (withdrawal potential, biomedical, psychiatric/cognitive, readiness to change, relapse potential, recovery environment) and let the highest-severity dimension set the floor of care. Withdrawal risk drives the medical/supervised level regardless of motivation.
Initiating buprenorphine too soon after the last full agonist dose - e.g., 6–8 hours after the last oxycodone or 12 hours after methadone - and then selecting 'precipitated withdrawal' as an unrelated complication when the patient acutely worsens.
Candidates remember 'buprenorphine has high affinity' but not the practical timing rule, and stems often present a patient who is 'motivated and in mild withdrawal,' which reads as ready.
What to do instead
Anchor to numbers: confirm mild-to-moderate objective withdrawal (COWS ≥8–12), wait ~12–24 hours after short-acting opioids, 24–48+ hours after long-acting, and 72+ hours after methadone. Low-dose ('microdose') induction is the answer when the stem involves a patient who cannot tolerate withdrawal.
Pairing medications with the wrong patient profile - offering naltrexone to a patient on chronic full-agonist opioids for pain, ordering disulfiram without baseline LFTs or a supervised-dosing plan, or starting acamprosate in advanced renal impairment.
Candidates learn the three alcohol medications as 'first-line options' and treat them as interchangeable, forgetting the contraindication and monitoring matrix that the exam tests heavily.
What to do instead
Build a three-column table (naltrexone / acamprosate / disulfiram) with indication, absolute contraindications, monitoring labs, and adherence requirements, and recite it before answering any pharmacotherapy item. Opioid analgesia or opioid use disorder on the med list means naltrexone is the wrong answer, not a 'consider with caution' answer.
Managing alcohol withdrawal with fixed-dose antipsychotic monotherapy, PRN-only benzodiazepines without a symptom-triggered protocol, or omitting thiamine/folate - and applying CIWA-Ar to opioid or benzodiazepine withdrawal.
Antipsychotics 'calm the patient' and seem safer to candidates worried about benzodiazepine misuse; CIWA-Ar is the only withdrawal scale many candidates have memorized, so it gets over-applied.
What to do instead
Match scale to substance: CIWA-Ar for alcohol, COWS for opioids, CIWA-B or a benzodiazepine taper for sedative-hypnotics. Benzodiazepines are first-line for alcohol withdrawal (symptom-triggered), antipsychotics are adjuncts only, and thiamine before glucose is non-negotiable.
Responding to a patient's ambivalence with confrontation, warning, or unsolicited advice - 'You need to stop or you'll lose your job,' followed by a list of treatment options - rather than reflective listening.
Candidates answer from clinical urgency and personal concern, and confrontation 'feels' like good care; exam stems with a resistant patient invite the candidate to argue.
What to do instead
When the stem shows low readiness or sustain talk, the correct response is an OARS reflection (simple or complex) or an evoking question, never a directive or a list. Apply the righting-reflex test: if the response tells the patient what to do before they have voiced it, it is wrong.
Coordinating care - faxing a discharge summary to the primary care clinic, calling a probation officer, or confirming enrollment status to a family member - without a 42 CFR Part 2-compliant written consent naming the specific recipient and purpose.
Candidates apply general HIPAA instincts ('it's treatment, so it's permitted'), not knowing Part 2 is stricter and requires patient-specific consent for most disclosures of SUD treatment records.
What to do instead
Default to 'obtain a compliant written consent' whenever the stem involves sharing SUD treatment information outside the treating program. Recall that consent must identify the program, the recipient, the purpose, and the revocation date, and that redisclosure notices are required.
Discharging a high-risk patient with only a referral list - no naloxone kit or overdose education, no discussion of fentanyl test strips or safer-use strategies, no warm handoff, and no documented follow-up appointment within 7 days.
Candidates treat harm reduction as separate from 'real' treatment and assume the referral itself closes the loop; the discharge items sound like adequate care in a multiple-choice format.
What to do instead
Treat naloxone provision plus overdose education as the default standard for anyone with opioid use, and treat a scheduled follow-up appointment within 7 days as the marker of a completed transition. When a stem offers 'give a list of AA meetings' versus 'provide naloxone, overdose education, and a direct appointment,' choose the latter.
Boundary and dual-role lapses - accepting a patient's gift or social media request, sponsoring a current or former client in 12-step recovery, hiring a client into a peer role they report to, or extensive personal self-disclosure in session.
Recovery-oriented care emphasizes authenticity and mutuality, and candidates over-apply that ethos to roles where the power differential and the therapeutic frame still apply; the 'warm' option often reads as the most client-centered one.
What to do instead
Apply the frame test: would the action make it harder to set limits or to discharge/transfer this person later? If yes, decline and document. The correct answer in these items is nearly always to maintain the professional role, refer to a separate peer/sponsor, and process the request in supervision.