Delusional Disorder

Delusional disorder is characterised by one or more firmly held false beliefs that persist for at least one (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 individuals with a paranoid personality disorder.
  • Medical professionals base the diagnosis mainly on an individual’s history after they rule out other possible causes.
  • Individuals usually remain functional and employed.
  • A good doctor-patient relationship is essential to treatment.

Delusional disorder usually first affects individuals 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;
  • Disorganised speech; or
  • Disorganised behaviour.

Delusions may involve situations that could conceivably occur in real life, such as being followed, poisoned, infected, loved at a distance, or deceived by a spouse or lover. 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 the individual continues to believe in a delusion no matter how much clear evidence contradicts it.

Types of Delusional Disorder

There are several sub-types of delusional disorder:

  • Erotomanic:
    • Individuals believe that another person is in love with them.
    • They often try to contact the object of the delusion through telephone calls, letters, or digital messages. Some attempt surveillance, and stalking is common.
    • Behaviour related to the delusion may be against the law.
  • Grandiose:
    • individuals are convinced that they have some great talent or have made some important discovery.
  • Jealous:
    • Individuals are convinced that a spouse or lover is unfaithful.
    • This belief is based on incorrect inferences supported by dubious evidence.
    • Under such circumstances, physical assault may be a significant danger.
  • Persecutory:
    • Individuals believe that they are being plotted against, spied on, maligned, or harassed.
    • Individuals may repeatedly file lawsuits or reports to the police or other government agencies.
    • Rarely, people resort to violence in retaliation for imagined persecution.
  • Somatic:
    • Individuals are preoccupied with a bodily function or attribute, such as an imagined physical deformity or odour.
    • The delusion can also take the form of an imagined medical disorder, such as having parasites.