Delusional disorder

Delusional disorder is a psychiatric diagnosis denoting a psychotic mental illness that involves holding one or more non-bizarre delusions in the absence of any other significant psychopathology (signs or symptoms of mental illness). In particular, a person with delusional disorder has never met any other criteria for schizophrenia and does not have any marked hallucinations, although tactile (touch) or olfactory (smell) hallucinations may be present if they are related to the theme of the delusion.

A person with delusional disorder can be quite functional and does not tend to show any odd or bizarre behavior except as a direct result of the delusional belief. "Despite the encapsulation of the delusional system and the relative sparing of the personality, the patient's way of life is likely to become more and more overwhelmed by the dominating effect of the abnormal beliefs". (Munro, 1999)

It is worth noting that the term paranoia was previously used in psychiatry to denote what is now called 'delusional disorder'. The modern psychiatric use of the word paranoia is subtly different but now rarely refers to this specific diagnosis.

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Indicators of a delusion

(Munro, 1999)

1. The patient expresses an idea or belief with unusual persistence or force.
2. That idea appears to exert an undue influence on his or her life, and the way of life is often altered to an inexplicable extent.
3. Despite his profound conviction, there is often a quality of secretiveness or suspicion when the patient is questioned about it.
4. The individual tends to be humorless and oversensitive, especially about the belief.
5. There is a quality of centrality: no matter how unlikely it is that these strange things are happening to him, the patient accepts them relatively unquestioningly.
6. An attempt to contradict the belief is likely to arouse an inappropriately strong emotional reaction, often with irritability and hostility.
7. The belief is, at the least, unlikely.
8. The patient is emotionally over-invested in the idea and it overwhelms other elements of his psyche (psychology).
9. The delusion, if acted out, often leads to behaviors which are abnormal and/or out of character, although perhaps understandable in the light of the delusional beliefs.
10. Individuals who know the patient will observe that his belief and behavior are uncharacteristic and alien.

Features

(Munro, 1999)

1. It is a primary disorder.
2. It is a stable disorder characterized by the presence of delusions to which the patient clings with extraordinary tenacity.
3. The illness is chronic and frequently lifelong.
4. The delusions are logically constructed and internally consistent.
5. The delusions do not interfere with general logical reasoning (although within the delusional system the logic is perverted) and there is usually no general disturbance of behavior. If disturbed behavior does occur, it is directly related to the delusional beliefs.
6. The individual experiences a heightened sense of self-reference. Events which, to others, are nonsignificant are of enormous significance to him or her, and the atmosphere surrounding the delusions is highly charged.

Types

• Erotomanic Type (see erotomania): delusion that another person, usually of higher status, is in love with the individual.
• Grandiose Type: delusion of inflated worth, power, knowledge, identity, or special relationship to a deity or famous person (e.g. see Jerusalem syndrome)
• Jealous Type: delusion that the individual's sexual partner is unfaithful (see delusional jealousy).
• Persecutory Type: delusion that the person (or someone to whom the person is close) is being malevolently treated in some way.
• Somatic Type: delusions that the person has some physical defect or general medical condition (for example, see delusional parasitosis).

A diagnosis of 'mixed type' or 'unspecified type' may also be given if the delusions fall into several or none of these categories.

Treatment

Getting a patient to seek a mental health professional and getting them to accept treatment is an extremely difficult process. There is no effective insight and because the delusion is held with extrordinary conviction, any attempt at contradiction is met with anger and disdain.

See also

• Delusion
• Monothematic delusions
• Paranoia
• Psychosis
• Schizophrenia

Further reading

• Munro, A. (1999) Delusional disorder. Cambridge: Cambridge University Press. ISBN 0-521-58180-X
• Sims, A. (1995) Symptoms in the mind: An introduction to descriptive psychopathology. Edinburgh: Elsevier Science Ltd. ISBN 0-7020-2627-1
• APA.(2000) "Diagnostic and Statistical Manual, Fourth Edition, Text Revision". Washington DC: American Psychiatric Association. ISBN 978-0890420249