Definition – Delusions are fixed and firmly held beliefs that have no basis in reality. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, or some other misleading effects of perception. Delusions are considered “bizarre” if they are clearly implausible and peers within the same culture cannot understand them. An example of a bizarre delusion is when an individual believes that his or her organs have been replaced with someone else’s without leaving any wounds or scars. An example of a nonbizarre delusion is the belief that one is under police surveillance, despite a lack of evidence.
According to the most recent version of the Diagnostic and Statistical Manual of Mental Disorders (DSM IV), delusion is defined as: “A false belief based on incorrect inference about external reality that is firmly sustained despite what almost everyone else believes and despite what constitutes the inconvertible and obvious proof or evidence to the contrary.”
Psychiatrist and philosopher Karl Jaspers first described the three main criteria that need to be met for a belief to be diagnosed as delusional. These were outlined in his 1917 work called “General Psychopathology” and include the following:
- The false belief is held with absolute certainty or conviction
- The belief remains unchanged despite proof that it is not true
- The belief is false, implausible, bizarre or impossible
There are several different types of delusional disorders, and each type captures a particular theme within a person’s delusions.
- Erotomanic: An individual believes that a person, usually of higher social standing, is in love with him or her.
- Grandiose: An individual believes that he or she has some great but unrecognized talent or insight, a special identity, knowledge, power, self-worth, or relationship with someone famous or with God.
- Jealous: An individual believes that his or her partner has been unfaithful.
- Persecutory: An individual believes that he or she is being cheated, spied on, drugged, followed, slandered, or somehow mistreated.
- Somatic: An individual believes that he or she is experiencing physical sensations or bodily dysfunctions, such as foul odors or insects crawling on or under the skin, or is suffering from a general medical condition or defect.
- Mixed: An individual exhibits delusions that are characterized by more than one of the above types, but no one theme dominates.
- Unspecified: An individual’s delusions do not fall into the described categories or cannot be clearly determined.
Causes and Symptoms – Delusional disorder is a rare condition and difficult to study; as a result, it is not widely discussed in clinical research. While the cause is unknown, some studies suggest that people develop delusions as a way to manage extreme stress or deal with a history of trauma. Genetics may also contribute to the development of a delusional disorder. Individuals are more likely to be diagnosed with the delusional disorder if they have family members with schizophrenia or schizotypal personality disorder.
The presence of non-bizarre delusions is the most obvious symptom of this disorder. Other symptoms that might appear include:
- An irritable, angry, or low mood
- Hallucinations (seeing, hearing, or feeling things that are not really there) that are related to the delusion
Diagnosed and Treatment – There are no laboratory tests to specifically diagnose the delusional disorder, the doctor might use various diagnostic tests — such as X-rays or blood tests — to rule out physical illness as the cause of your symptoms. According to the DSM-5, a diagnosis of the delusional disorder is made if a person has non-bizarre delusions for at least one month and does not have the characteristic symptoms of other psychotic disorders, such as schizophrenia.
According to the DSM-5, a diagnosis of the delusional disorder is made if a person has non-bizarre delusions for at least one month and does not have the characteristic symptoms of other psychotic disorders, such as schizophrenia.
Antipsychotic medications may be used in the treatment of the delusional disorder, although research on the efficacy of this form of treatment has been inconclusive. Antidepressants, such as SSRI’s and clomipramine, have also been successfully used for the treatment of the somatic type delusional disorder.
Psychotherapies that may be helpful in delusional disorder include individual psychotherapy, cognitive-behavioral therapy (CBT), and family therapy.