A psychotic condition characterized by persistent, non-bizarre delusions without other prominent psychotic symptoms
1. Definition & Diagnostic Criteria (DSM-5)
Delusional Disorder is marked by:
✅ Fixed false beliefs (delusions) lasting ≥1 month
✅ No other psychotic symptoms (e.g., hallucinations may be minimal/tactile)
✅ Normal functioning outside the delusional topic
✅ Not caused by substances or other medical conditions
Key Features:
- Delusions are non-bizarre (plausible but untrue, e.g., being followed vs. alien mind control)
- Unlike schizophrenia, cognition and affect remain relatively intact
2. Subtypes & Common Themes
| Subtype | Delusion Content | Prevalence |
|---|---|---|
| Persecutory | Belief of being harmed/spied on | Most common |
| Grandiose | False superiority (e.g., secret genius) | ~10% cases |
| Jealous | Partner’s infidelity (Othello syndrome) | ~5% |
| Erotomanic | Someone famous loves them (de Clérambault) | Rare |
| Somatic | Body dysfunction (e.g., parasites) | ~15% |
Note:
- Mixed type and unspecified subtypes also exist
3. Causes & Risk Factors
- Genetic: Mild familial link to psychotic disorders
- Neurochemical: Dopamine dysregulation in limbic system
- Psychological:
- Social isolation
- Paranoid personality traits
- Sensory impairments (e.g., hearing loss in elderly)
Myth Buster:
❌ “These people are dangerous” → False. Most are not violent (except rare jealous subtype cases).
4. Diagnosis Challenges
Differential Diagnosis:
- Schizophrenia: Has broader psychotic symptoms
- Mood disorders with psychosis: Delusions align with mood
- Dementia: Progressive cognitive decline
Assessment Tools:
- Clinical interviews focusing on belief flexibility
- Collateral history (family/friends often spot inconsistencies first)
5. Treatment Approach
A. Medications
- Antipsychotics (Pimozide for somatic delusions; Risperidone commonly used)
- SSRIs if comorbid OCD/depression
B. Psychotherapy
- CBT to challenge delusional evidence
- Motivational interviewing to improve insight
C. Social Interventions
- Address isolation (social clubs, volunteer work)
- Family psychoeducation
6. Prognosis
- Highly variable: Some resolve in months; others persist for decades
- Better outcomes when:
- Early treatment initiation
- Good pre-morbid relationships
- Delusions are circumscribed (not pervasive)
7. Key Differences from Similar Disorders
| Feature | Delusional Disorder | Schizophrenia | Paranoid PD |
|---|---|---|---|
| Delusions | Non-bizarre, organized | Bizarre, disorganized | No fixed delusions |
| Functioning | Preserved outside topic | Globally impaired | Interpersonally strained |
| Insight | Often lacking | Severely impaired | Defensive but aware |
8. How to Support Someone
✅ Avoid direct confrontation (fuels defensiveness)
✅ Focus on distress (“I see this worries you”) vs. truth
✅ Encourage general medical care (builds trust for later MH referral)
9. Notable Cases
- King George III (possibly had porphyria but exhibited persecutory delusions)
- Daniel Paul Schreber (memoir inspired Freud’s psychosis theories)
10. Resources
- Book: The Impossible Profession (explores delusional patients)