A 30-year-old man believes he is receiving special messages through the TV meant only for him, but his functioning is preserved, he has no formal thought disorder or hallucinations, and the delusion has been present for 4 months. The MOST likely diagnosis is:
- A Paranoid schizophrenia
- B Delusional disorder ✓
- C Brief psychotic disorder
- D Schizophreniform disorder
Correct answer: B. Delusional disorder
Explanation
Delusional disorder (DSM-5) is characterised by non-bizarre delusions persisting ≥1 month without prominent hallucinations, formal thought disorder, or significant functional impairment — functioning is relatively preserved. Schizophrenia requires ≥6 months of symptoms (including prodrome/residual); schizophreniform disorder 1–6 months of active-phase symptoms with functional decline; brief psychotic disorder <1 month. This patient's isolated, systematised delusion with intact functioning for 4 months best fits delusional disorder.
Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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