Misconception Repair Lab

Treating any fixed false belief as automatically schizophrenia

(or reveal each step yourself below)

1. The tempting shortcut
"There's a fixed false belief here, so this must be schizophrenia."
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

F20 and F22 both feature delusions, but they answer different classification questions. F22 exists precisely because a persistent, organised, single-theme delusion — even a dramatic or distressing one — is not, by itself, evidence of the broader disturbance F20 requires. Skipping this check leads to over-diagnosing schizophrenia in people whose presentation is actually much narrower.
4. Reveal — the better reasoning rule
- Is there only one delusion or one closely related set of delusions, or is the picture broader (hallucinations, thought disorder, negative symptoms)?
- Is functioning outside the delusional theme largely preserved, or is there broader disruption to speech, affect and behaviour?
- Has the belief persisted for at least three months, or is it more recent and possibly still evolving (which may point toward F23 instead)?
Corrective example: Elif (see the F22 worked example) holds one detailed, persistent persecutory belief about a coworker, but her speech, affect, work performance and friendships are otherwise unaffected, and she has no hallucinations — the narrowness of the picture, not the intensity of the belief, is what supports F22 over F20.

5. Try the transfer case

Apply the better rule above to a fresh case.