Delusional disorder, previously called paranoid disorder, is a type of serious mental illness called a psychotic disorder. People who have it can’t tell what’s real from what is imagined.
Delusions are the main symptom of delusional disorder. They’re unshakable beliefs in something that isn’t true or based on reality. But that doesn’t mean they’re completely unrealistic. Delusional disorder involves delusions that aren’t bizarre, having to do with situations that could happen in real life, like being followed, poisoned, deceived, conspired against, or loved from a distance. These delusions usually involve mistaken perceptions or experiences. But in reality, the situations are either not true at all or highly exaggerated.
A bizarre delusion, by contrast, is something that could never happen in real life, such as being cloned by aliens or having your thoughts broadcast on TV. A person who has such thoughts might be considered delusional with bizarre-type delusions.
