Delusional disorder is a condition where a person has a fixed, firm belief about imaginary but not impossible situations, but has no other symptoms of a psychotic or mood disorder. It has several subtypes. In delusional disorder, delusions may include:
- believing one is being followed or watched
- believing a spouse is unfaithful when this is not the case
- believing one has an unusual illness such as plague or scurvy
- believing one has a special relationship with a celebrity
A person with delusional disorder may seem completely normal except for holding to a single delusion.