Delusional disorder is characterized by one or more false beliefs that persist for at least 1 month.
Delusional disorder usually first affects people in middle or late adult life. 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
After ruling out other specific conditions that are associated with delusions, 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 to act on the delusions.
Delusional disorder does not usually cause severe impairment. However, people may become progressively more involved with their delusion. Most people are able to remain employed.
A good doctor-patient relationship helps. 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.
Last full review/revision September 2014 by S. Charles Schulz, MD