ICD-10 code: F22
Delusional disorder is part of a cluster of diagnoses called the schizophrenia spectrum and other psychotic disorders. Schizophrenia spectrum and other psychotic disorders are a group of psychiatric conditions that include:
These disorders are characterized by symptoms that can be divided into two groups: positive and negative.
Positive symptoms include delusions, hallucinations, disorganized thinking (speech), and grossly disorganized or abnormal motor behavior (including catatonia). Delusions are fixed beliefs that are not amenable to change in light of conflicting evidence. Hallucinations are perception-like experiences that occur without external stimulus. Disorganized thinking/speech is characterized by a derailment or loose associations in an individual's speech pattern. Grossly disorganized or abnormal motor behavior is a difficulty in sustaining goal-oriented behavior. This may manifest itself in a variety of ways, ranging from childlike "silliness" to unpredictable agitation.
Negative symptoms include diminished emotional expression, avolition, alogia and anhedonia. Negative symptoms are those that involve a loss of normal function or experience. Diminished emotional expression is the reductions in the expression of emotions in the face, eye contact, intonation of speech, and movement of hand, head, and face that normally give an emotional emphasis to speech. Avolition is a decrease in motivated self-initiated purposeful movement. Alogia is manifested by diminished speech output. Anhedoia is the decreased ability to experience pleasure from positive stimuli.
Delusions are false beliefs based on incorrect inference about external reality that persist despite the evidence to the contrary and these beliefs are not ordinarily accepted by other members of the person's culture or subculture.
Delusional Disorder involves the presence of one or more delusions with a duration of 1 month or longer. One can only have delusional disorder if it has been established that the individual does not have schizophrenia. Specifically, the following schizophrenia symptoms must be absent:
In addition, the following criteria apply:
Delusions and delusional disorder typically fall into one of the following categories:
In addition, delusions may or may not be bizarre. Delusions are deemed bizarre if they are clearly implausible, not understandable, and not derived from ordinary life experiences (e.g., an individual's belief that a stranger has removed his or her internal organs and replaced them with someone else's organs without leaving any wounds or scars).
Nonbizarre delusions are about situations that could occur in real life, such as being followed, being loved from a distance, being poisoned, having an infection, or being deceived by one's spouse. These delusions usually involve the misinterpretation of perceptions or experiences. In reality, however, the situations are either not true at all or highly exaggerated.
Although delusions might be a symptom of more common disorders, such as schizophrenia, delusional disorder itself is rather rare. The lifetime prevalence of Delusional Disorder is 0.2%, and the most frequent subtype is persecutory. Delusional disorder most often occurs in middle to late life and is slightly more common in women than in men. The jealous subtype, however, is more common among men.
People with delusional disorder often can continue to socialize and function normally, apart from the subject of their delusions, and generally do not behave in an obviously odd or bizarre manner. This is unlike people with other schizophrenia spectrum and other psychotic disorders, who also might have delusions as a symptom of their disorder. In some cases, however, people with delusional disorder might become so preoccupied with their delusions that their lives are disrupted. Many individuals with delusional disorder develop irritable, anxious or depressed mood, which can be a reaction to maladaptive delusional beliefs. Anger and violent behavior can occur with persecutory, jealous, and erotomanic types of delusional disorder. Those with persecutory delusions may engage in litigious or antagonistic behavior. Legal difficulties often occur in jealous and erotomanic types.
Making a distinction between a delusion and an overvalued idea is important, the latter representing an unreasonable belief that is not firmly held. Additionally, personal beliefs should be evaluated with great respect to complexity of cultural and religious differences; some cultures have widely accepted beliefs that may be considered delusional in other cultures.
There appears to be a genetic component to delusional disorder, and there is a significant familial relationship with Schizophrenia and Schizotypal Personality Disorder.
Medications
Currently there is an overall lack of evidence-based information about the treatment of delusional disorder and insufficient evidence to make treatment recommendations. In the absence of such research, the treatment of delusional disorder typically consists of those that are considered effective for other psychotic disorders and mental health problems. Treatment usually includes a combination of antipsychotic medication with cognitive therapy or supportive therapy.
Some studies show that close to half of patients treated with antipsychotic medications show at least partial improvement. However, there are few studies which confirm the use of any specific medications for this disorder.
Psychotherapy
Delusional disorder can be very difficult to treat because its sufferers may lack insight that psychiatric problem exists. Indeed, this is one of the key differences between delusional disorder and other primary psychotic disorders. However, individuals may not seek psychiatric help, may remain isolated, and may present instead to internists, surgeons, dermatologists, policemen, and lawyers rather than mental health professionals.
The overriding factor in determining psychotherapy success is the quality of the patient/therapist relationship. Early in the therapy, it is vital not to directly challenge the delusion system or beliefs and instead to concentrate on realistic and concrete problems and goals within the person's life. Therapy approaches which focus on insight or self-knowledge may not be as beneficial as those stressing social skills training and other behaviorally and solution-oriented therapies. Even if the client is willing, therapy is likely to take a fair amount of time, from at least 6 months to a year.
Psychotherapies that may be helpful in delusional disorder include the following:
Non-Recommended Treatments
Because of the potential for harm and/or reactivity, the following treatments are not recommended:
Additional Treatments to Consider