F22 — Persistent delusional disorders

What is this category?

F22 describes people who hold one delusion, or a set of closely related delusions, for a long period — often years — with the rest of their thinking, speech, affect and daily functioning remaining largely intact outside the delusional theme. The delusions are frequently plausible-sounding rather than bizarre (persecution, jealousy, litigation, or somatic concerns are common themes), which is part of why this category is easy to confuse with ordinary suspiciousness on one side and with a broader psychotic illness on the other.

Core diagnostic concept

The classification question F22 answers is: "is there one delusion, or a small set of related delusions, that has persisted for a substantial period, without the broader disturbance (characteristic hallucinations, thought disorder, negative symptoms) that would point to F20, and without it being induced by a close relationship with someone else who already holds the belief?" F22 is about the narrowness and persistence of the belief system, not its plausibility or its emotional intensity.

Key diagnostic features

One delusion or a set of related delusions

A single theme (or a small number of closely related themes) dominates the clinical picture, rather than a broad mix of unrelated symptoms.

Often non-bizarre content

Common themes include persecution, jealousy, litigation, grandiosity, or somatic concerns — beliefs that, while false, are not culturally implausible in the way thought broadcast or alien control would be.

Long duration

The delusional system is typically present for at least three months, and often for years, before this category is confidently applied.

Preserved personality and functioning outside the theme

Behaviour, affect and thinking outside the delusional theme are often unremarkable, and the person may continue working and maintaining some relationships, sometimes for a long time.

Absence of a broader schizophrenic picture

Characteristic hallucinations, thought disorder, and negative symptoms are absent or, if present at all, are not persistent or prominent — the delusional system stands largely on its own.

Occasional brief mood symptoms

Depressive symptoms may occur, understandably, in relation to the delusional beliefs, but do not dominate the picture the way a mood episode would.

How to weigh evidence

These learning labels are teaching aids, not official ICD-10 terminology (see Sources and Method).

• supports A single, organised persecutory belief held for over a year, described in detailed and internally consistent terms, with ordinary speech and affect outside the topic.
• consistent not decisive The person continues to work and maintain family relationships despite the belief.
• raises alternative A close family member who lives with the person has independently come to share the exact same belief only after the relationship began.
• contradicts or weakens Persistent third-person commentary hallucinations or marked thought disorder occurring alongside the delusion.
• missing and necessary to ask Whether anyone else in the person's household or close circle shares the belief, and if so, who held it first.

Duration and course

Minimum duration: The delusion or delusional system should have been present for at least three months before this category is confidently applied.

Course: Course is typically chronic, sometimes lifelong, occasionally with periods of partial remission. Unlike F23, this is not a brief, self-resolving presentation.

Included presentations

• A single, long-standing, non-bizarre delusion (e.g. persecutory, jealous, litigious, or somatic) with otherwise preserved functioning and no broader psychotic picture.
• A small set of closely related delusions sharing one theme, persisting over a similar timeframe.

Exclusions and distinguishing presentations

Four-character subtypes (orientation)

These four-character subtypes are shown for orientation only. This product does not teach or simulate four-character coding decisions; the category-level (three-character) reasoning above is the learning target.

F22.0 — Delusional disorder

The main, most commonly used subtype: a single delusion or set of related delusions other than those listed as specific to schizophrenia, present for at least three months and clearly personal rather than culturally shared. (taught for orientation only, not separately assessed in this pilot)

F22.8 — Other persistent delusional disorders

A residual subtype for persistent delusional presentations that do not fit F22.0's stricter description. (taught for orientation only, not separately assessed in this pilot)

F22.9 — Persistent delusional disorder, unspecified

Used when the disorder is confidently persistent-delusional in nature but insufficient detail is available to select a more specific subtype. (taught for orientation only, not separately assessed in this pilot)

External causes to check first

Categories in this block require that the disturbance is not better explained by another external cause listed below. These short capsules are reminders, not full teaching modules.

Common learner errors

• Common mistake: Treating any fixed false belief as automatically schizophrenia

Worked example — one persistent, organised belief

Elif, 47, has for the past two years been convinced that a coworker has been secretly recording her phone calls and forwarding them to her employer to have her fired. She describes this in detailed, internally consistent terms whenever it comes up, has changed her commute route and phone habits 'to be safe,' and has made a formal complaint to management, but otherwise continues to work full-time, maintains her friendships, and shows no unusual speech, affect, or behaviour outside this topic. She has never had hallucinations and no one else in her life shares the belief.

1. Step 1 — Check for a broader schizophrenic picture: no hallucinations, thought disorder, or negative symptoms are described; the disturbance is confined to one theme.
2. Step 2 — Check duration: the belief has persisted for two years, well past the three-month threshold.
3. Step 3 — Check whether the belief was induced by someone else: no one else shares it, so F24 does not apply.
4. Step 4 — Check functioning outside the theme: work, friendships, speech and affect are all preserved, consistent with a narrow delusional system rather than a broad disturbance.
5. Conclusion — F22 is best supported: one persistent, organised, non-bizarre delusion without a broader psychotic picture or evidence of induction from another person.

Interactive practice

• Type A One belief, two years, otherwise unremarkable Recognition / application · Foundation
• Type B A belief that arrived with a roommate Boundary / differential · Boundary
• Type C Six weeks in, one fixed idea Insufficient information · Developing
• Type D The picture broadens Progressive revision · Transfer
• Type E A dramatic belief, otherwise unremarkable Misconception correction · Foundation
• Type F Sorting the evidence — one belief, one household Explanation and evidence selection · Boundary

Retrieval prompts

Try answering each of these from memory before revealing where to check. Nothing you think or type here is sent or saved anywhere.

1. What is the single most important duration threshold for F22, and why does it matter?

   Reveal answer location

   Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.

   I recalled this I need to review this

2. Name one feature that would make you reconsider F20 instead of F22.

   Reveal answer location

   Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.

   I recalled this I need to review this

3. Explain why 'this belief could theoretically be true' is not the test that separates a delusion from an ordinary suspicion.

   Reveal answer location

   Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.

   I recalled this I need to review this

These self-checks are a personal study aid only, visible to you on this page for this visit — they are not stored and do not affect your mastery dimensions.

Related glossary terms

• Psychosis

  A general descriptive term for a mental state in which a person's grasp of reality is significantly disturbed — typically through delusions, hallucinations, or marked thought disorder. Psychosis is a feature that can occur across many different categories, not a diagnosis in itself.

  Open full glossary entry →

• Delusion

  A fixed, false belief that is firmly held despite clear evidence to the contrary, and that is not accounted for by the person's cultural or religious background.

  Open full glossary entry →

• Insight (clinical)

  The degree to which a person recognises that their experiences (such as unusual beliefs or perceptions) may reflect an illness rather than external reality. Insight can vary and is not itself a classification criterion, but is often noted educationally.

  Open full glossary entry →