Delusional disorder is characterized by one or more false beliefs that persist for at least 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 people with a paranoid personality disorder.
Doctors base the diagnosis mainly on the person’s history after they rule out other possible causes.
People usually remain functional and employed.
A good doctor-patient relationship is essential to treatment.
Delusional disorder usually first affects people in middle or late adult life. It is less common than schizophrenia.
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 belief is that people continue to believe in a delusion no matter how much clear evidence contradicts it.
Several subtypes of delusional disorder are recognized:
Erotomanic: People believe that another person is in love with them. Efforts to contact the object of the delusion through telephone calls, letters, or even surveillance and stalking are common. Behavior related to the delusion may cause conflict with the law.
Grandiose: People are convinced that they have some great talent or have made some important discovery.
Jealous: People 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: People believe that they are being plotted against, spied on, maligned, or harassed. People may repeatedly attempt to obtain justice by appealing to courts and other government agencies. Rarely, violence may be resorted to in retaliation for imagined persecution.
Somatic: People are preoccupied with a bodily function or attribute, such as an imagined physical deformity or odor. The delusion can also take the form of an imagined medical disorder, such as a parasitic infection.
A delusional disorder may develop from a preexisting paranoid personality disorder. Beginning in early adulthood, people with a paranoid personality disorder have a pervasive distrust and suspiciousness of others and their motives.
Early symptoms of delusional disorder may include
Behavior is not obviously bizarre or odd. People with delusional disorder tend to function relatively well, except when their delusions cause problems. For example, they may have marital problems if they are incorrectly convinced their spouse is being unfaithful.
After ruling out other specific conditions that can cause delusions (such as substance abuse), a doctor bases the diagnosis largely on the person’s history and symptoms. The doctor also must assess how dangerous the person might be, particularly how likely the person is to act on the delusions.
Treatment can be difficult because some people firmly believe their delusion and refuse to seek help. A good doctor-patient relationship helps. Once a relationship is established, doctors can encourage people who are resistant to being treated to participate in treatment.
Hospitalization may be needed if the doctor believes that people are dangerous.
Antipsychotic drugs are not generally used but are sometimes effective in suppressing symptoms.
A long-term treatment goal is to shift the person’s focus away from the delusion to a more constructive and gratifying area, although this goal is frequently difficult to achieve.