Misconception Repair Lab

Treating a single defiant or antisocial episode as sufficient for a conduct disorder

(or reveal each step yourself below)

1. The tempting shortcut
"He hit another student, so that's conduct disorder."
2. Stop and think
Before you read on: what is wrong with this reasoning? Try to answer in your own words, then reveal the explanation below.
3. Reveal — why it fails

F91 requires a repetitive and persistent pattern of dissocial, aggressive, or defiant conduct, typically judged over six months or more — not a single incident, however serious. Adolescents and children commonly have isolated episodes of poor judgement or rule-breaking as part of typical development; treating any one such episode as diagnostic conflates ordinary, time-limited misbehaviour with a genuinely persistent behavioural pattern, and risks unfairly labelling a young person based on one moment.
4. Reveal — the better reasoning rule
- Does the vignette establish a repeated, ongoing pattern over a meaningful period, or only a single incident?
- Is there evidence of similar behaviour before or after the described episode, or does the vignette explicitly note this was an isolated event?
- A single act, however serious, should weigh against F91 unless the vignette also establishes a broader persistent pattern.
Corrective example: In F91's boundary case, a single episode of shoplifting with no other reported dissocial or aggressive behaviour before or since does not meet F91 — the persistent pattern the category requires is not established by one incident alone.

5. Try the transfer case

Apply the better rule above to a fresh case.