Delusional disorder is characterized by one or more firmly held false beliefs that persist for at least 1 month.
- The false beliefs may be ordinary things that could occur (such as being deceived by a spouse) or things unlikely to occur (such as having internal organs removed without leaving a scar).
- This disorder may develop in people with a paranoid personality disorder.
- Doctors base the diagnosis mainly on the person’s history after they rule out other possible causes.
- People usually remain functional and employed.
- A good doctor-patient relationship is essential to treatment.
Delusional disorder usually first affects people in middle or late adult life. It is less common than schizophrenia. Delusional disorder is distinguished from schizophrenia by the presence of delusions without any of the other symptoms of psychosis (for example, hallucinations, disorganized speech, or disorganized behavior).
Delusions may involve situations that could conceivably occur in real life, such as being followed, poisoned, infected, or loved at a distance. Or they may involve situations that are very unlikely to occur, such as having internal organs removed without leaving a scar. The difference between a delusion and a false or mistaken belief is that people continue to believe in a delusion no matter how much clear evidence contradicts it.