Home > Encyclopedia of Mental Disorders > Delusional disorder

Definition

Delusional disorder is characterized by the presence of recurrent, persistent non-bizarre delusions.

Delusions are irrational beliefs, held with a high level of conviction, that are highly resistant to change even when the delusional person is exposed to forms of proof that contradict the belief. Non-bizarre delusions are considered to be plausible; that is, there is a possibility that what the person believes to be true could actually occur a small proportion of the time. Conversely, bizarre delusions focus on matters that would be impossible in reality. For example, a non-bizarre delusion might be the belief that one's activities are constantly under observation by federal law enforcement or intelligence agencies, which actually does occur for a small number of people. By...