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ICD-10 Learning Lab Exit Presentation Mode

Category: F20 F21 F22 F23 F24 F25 F28 F29

F29 — Unspecified nonorganic psychosis: facilitator sheet

Teaching objective

The classification question F29 answers is: "is this confidently a nonorganic psychosis, with genuinely insufficient information to say anything more specific, even at the level of an atypical picture?" F29 is not a shortcut for a case that simply feels complicated — it is reserved for a genuine information gap that specificity cannot yet fill.

Choose material

Worked example · Case: An unidentified man, no history, first contact · Case: Actually, there's enough to say more · Case: A secondhand report, nothing more

Worked example

Show scenario

An unidentified man, appearing to be in his 30s, is brought to an emergency department by police after being found acutely agitated and responding to unseen stimuli in a public place. He cannot give a coherent history, no identification or collateral contact is available, and there has been no opportunity yet for extended observation or a medical work-up. Staff note he appears psychotic but cannot yet say more.

(or reveal one step at a time below)
  1. Reveal step 1

    Step 1 — Confirm psychosis is present: agitation and responding to unseen stimuli support this.

  2. Reveal step 2

    Step 2 — Check whether an organic or substance cause can be assessed: not yet — no work-up has been possible.

  3. Reveal step 3

    Step 3 — Check whether any F20-F25 category, or even an F28-type atypical description, can be supported: no history, no collateral information, and no observation time are available to do so.

  4. Reveal step 4

    Step 4 — Recognise this as a genuine information gap, not a complicated but describable picture.

  5. Reveal step 5

    Conclusion — F29 is the best provisional answer: confidently psychotic, presumed nonorganic pending work-up, with insufficient information to specify further at this first contact.

Comparison points

F29 is distinguished from F28 by the amount of information available, not by the picture itself: F28 requires enough detail to describe a specific atypical picture that doesn't fit F20-F25; F29 is used when even that level of description is not yet possible. F29 is distinguished from F20-F25 simply by the absence of the specific information each of those categories requires — it is not a 'safer' or 'milder' alternative to them, only a less specific one.

Misconception prompt

Reaching for a residual category (F28/F29) instead of doing the classification work: "This case doesn't obviously fit a named category, so it must be 'other' or 'unspecified.'"

Ask the class why this reasoning fails before revealing the explanation below.

Reveal why it fails

F28 and F29 are the least informative categories in the block, and using them prematurely wastes the classification work the more specific categories are designed to capture. F28 specifically requires enough detail to describe a real atypical picture; F29 specifically requires that this level of detail genuinely is not available. Neither is a shortcut for 'I haven't checked the other categories yet' or 'this seems unusual.'

Discussion prompts

(or reveal one at a time below)
  1. Prompt 1

    What is the key difference between F29 and F28?

  2. Prompt 2

    Why is F29 considered a provisional label rather than a stable long-term classification?

  3. Prompt 3

    Name one piece of information that, if it became available, might move a case from F29 to a more specific category.

Summary

A confidently nonorganic psychosis with genuinely insufficient information available to specify a category, even an atypical one.