Curriculum · Mental Health / Psychiatry
Delusional disorder
What it is
The difference between delusional disorder and schizophrenia is sometimes blurred, and two features carry it: 1) the delusions are non-bizarre, though not always, and that is not part of the diagnostic criteria; 2) the impairment in function is not as pronounced as in schizophrenia, and the behavior is not odd or disorganized. In short, non-bizarre delusions only, with good functioning, point to delusional disorder, while bizarre delusions with thought withdrawal or thought control always favor schizophrenia.
How it presents
Good functioning is what stands out. A man of 58 who has held the belief for the last 5 years that his neighbor is trying to get him evicted from his apartment by telling lies about him to the landlord, and who has a successful marriage and has been working full time as a teacher for over 30 years, carries a belief of this non-bizarre kind alongside a life that still runs. Schizophreniform disorder, brief psychotic disorder and shared psychotic disorder are the other diagnoses put beside it.