Last reviewed:
14th Nov 2022
PharmD, BCPS
People with delusional disorder experience irrational beliefs called delusions, typically treated with medication and therapy. The typical age of onset is around 40 years, but medical professionals can diagnose delusional order at any time during adulthood.
Delusional disorder is a mental health condition listed in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). People with delusional disorder experience at least one delusion, lasting for at least a month. People who live with this mental health condition may have psychotic symptoms that appear similar to schizophrenia, but they do not meet the full diagnostic criteria for schizophrenia. When people with delusional disorder experience hallucinations, they must be related to the content of the delusions [1].
Different types of delusional disorders can vary based on the content of a person’s delusions. These types are outlined below [2]:
People with delusional disorder have one or more irrational beliefs, called delusions. In most cases, people with delusional disorders function well, and their behavior does not appear bizarre [2].
Some specific symptoms of delusional disorder are as follows [2]:
A mental health provider, like a psychiatrist, can diagnose delusional disorder. To diagnose this condition, a mental health professional will look for the following criteria, which are contained in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM 5) [2]:
In addition to performing a psychiatric evaluation to diagnose delusional disorder, a professional may conduct additional testing, such as a urine drug test, to rule out substance-induced delusions. Medical professionals may also consult friends and family members about the timeline of the delusions and any other symptoms a person has to rule out alternative psychiatric diagnoses. In addition, since other mental health conditions can appear similar to delusional disorders, a mental health professional often has to evaluate the criteria of other mental health conditions, like schizophrenia or schizoaffective disorder, to rule out alternative diagnoses [2].
When a clinician diagnoses delusional disorder, they will rule out related psychiatric conditions to ensure that they have made an accurate diagnosis. Some other conditions that may look similar to delusional disorder are as follows:
There is not one single cause of delusional disorder, and experts disagree on the leading causes of the condition because so little research has been conducted. However, some of the following risk factors may contribute to the development of delusional disorder, based on what is known about the condition:
There are no known ways to prevent delusional disorder. Sometimes, a person may have a genetic risk factor that predisposing them to develop the condition. The best way to avoid severe impairment from delusional disorder is to seek early intervention as soon as symptoms appear. Then, with a diagnosis and professional treatment, people can learn to manage symptoms of delusional disorder.
In most cases, delusional disorder is treated with a combination of medications and therapy. These options are discussed in more detail below. First, it is helpful to understand that since delusional disorder is quite rare, experts have not conducted much research on treatments explicitly used for this condition. Instead, much of what is known about treating delusional disorder comes from research on treating other psychotic disorders like schizophrenia.
Delusional disorder is often treated with antipsychotic medications. Specifically, a prescription medication called clozapine is often used as an effective treatment option for delusional disorder [7]. A doctor can help you to determine the best dosage and medication to treat your symptoms.
Medical professionals can recommend either first-generation (older) or second-generation (newer) antipsychotic medications for the treatment of delusional disorder [7]. These medications are listed below [8].
Therapy can help patients with delusional disorder to develop coping skills and learn to manage their symptoms. A modality called cognitive behavioral therapy (CBT) can help process logical errors and anxiety surrounding delusions [7]. Cognitive behavioral therapy teaches people to replace irrational, unhelpful thoughts with different ways of thinking.
Another type of therapy, called meta-cognitive therapy, has also shown benefit for patients with delusional disorder. This type of therapy reduces the severity of delusions by targeting biases in logical reasoning and then challenging delusional beliefs [9].
These are not the only treatment modalities that may work for a person with delusional disorder, but they are the most heavily researched. Unfortunately, given the rarity of delusional disorder, it has not been the focus of a significant amount of research, so future studies need to be conducted to determine other methods for treating the condition.
If your loved one has symptoms of delusional disorder, there are things you can do to be supportive. First, when approaching your loved one, remember to remain positive. Avoid blaming them for their problems or accusing them of being illogical.
Attempting to talk your loved one out of their delusions is unlikely helpful. Instead, you can offer a listening ear, express that you understand their anxious thoughts, and encourage them to seek treatment.
Based on what is known about delusional disorder, many people with this condition do not have significant impairment. In fact, they tend to function well psychologically when not discussing their delusion [2].
Some people with delusional disorder may experience difficulties at work and social isolation. However, treatment can help. The prognosis with treatment is generally good, and nearly half of patients with delusional disorder will respond well to medication [2].
While people with delusional disorder generally function well, there can be complications if the condition is untreated. For instance, some patients may develop symptoms of depression because of the stress associated with delusions. Others may have legal problems, as they may harass or stalk a person who is the object of delusional thinking, ultimately leading to criminal charges. People with delusional disorder may also become socially isolated because delusional thinking can interfere with relationships.
Delusional disorder is rare, with estimates that just 0.02% of the population experiences this mental health condition. Compared to other conditions, such as schizophrenia and mood disorders, delusional disorder is uncommon. Prevalence rates of the condition may be underestimated, as not everyone with delusional disorder seeks treatment [2].
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