Delusional disorder is best described as which of the following?

• A. Delusional disorder
• B. Schizophrenia
• C. Schizophreniform
• D. Mood disorder with psychotic features

Answer: (A)

Delusional disorder centers on a fixed, false belief that persists for a month or longer, with functioning that is not notably impaired outside the delusion and without prominent hallucinations, disorganized thinking, or other sustained psychotic symptoms. This profile sets it apart from schizophrenia, which involves a broader range of psychotic symptoms (such as hallucinations and disorganized speech) and more obvious impairment in daily functioning. It also differs from schizophreniform, where the same psychotic features appear but the duration is typically 1 to 6 months. Mood disorder with psychotic features involves psychosis that occurs only during mood episodes, with mood symptoms being a prominent part of the presentation. Therefore, the best match is delusional disorder, reflecting a prominent, longstanding delusion with relatively preserved function and minimal other psychotic features.