F91 — Conduct disorders

Concept, in one sentence

A persistent, repeated pattern of dissocial, aggressive, or defiant conduct beyond ordinary childhood mischief — never a single act, and never a judgment on the child's character.

Decisive boundary cues

• Repeated pattern over 6+ months -> weighs toward F91.
• One isolated incident, no other pattern -> weighs against F91.
• Confined to the family context only -> F91.0; poor peer relationships -> F91.1; well-integrated peer group -> F91.2.

Duration/course cue

A persistent pattern, typically over 6 months or more, is required — not a single incident.

Nearest alternatives

F90, F92, F93

Common mistake

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

Retrieval prompt — one-line memory anchor

What would you need to confirm before concluding this is a persistent pattern rather than an isolated incident?