People with delusional disorder are often able to continue living relatively normal lives outside the content of their delusions. Unlike other psychotic spectrum disorders, delusional disorder typically does not involve bizarre or highly unusual behavior. However, in some cases, individuals may become so preoccupied with their delusions that their ability to function fully in daily life is significantly impaired.

What Is Delusional Disorder?

Delusional disorder is characterized by the presence of one or more persistent false beliefs that last for at least one month. These delusions are the primary - and sometimes only - symptom of the disorder. The delusions may involve non-bizarre scenarios that could occur in real life, such as being followed, poisoned, conspired against, or deceived.
Even in these cases, however, the beliefs are either entirely false or grossly exaggerated.

Bizarre delusions, by contrast, involve implausible scenarios - for example, believing that an organ was removed from the body without leaving any physical trace.

There are several subtypes of delusional disorder:

• Erotomanic type: The person believes that another individual - often someone of higher status- is in love with them. They may try to make contact with the object of their delusion, which can escalate into stalking behavior.
   
• Grandiose type: This is perhaps the most well-known type. It involves an inflated sense of self-importance, believing oneself to possess exceptional talent, knowledge, or a special mission.
   
• Jealous type: The individual is convinced that their partner is being unfaithful, based on misinterpreted evidence or unfounded suspicions. These beliefs can lead to aggression or violence against the partner.
   
• Persecutory type: The person believes that they are being targeted by others, followed, conspired against, or harassed.
   
• Somatic type: The delusion is related to physical sensations or bodily functions - e.g., believing one has parasites, emits a foul odor, or has a physical deformity.
   
• Delusions of thought broadcasting or control: The individual may believe that their thoughts are being transmitted via television, the internet, or other media, or that external forces are controlling their mind.
   

Causes

The exact cause of delusional disorder remains unknown. However, it is not considered an early stage of schizophrenia or bipolar disorder, and no strong genetic link with schizophrenia has been identified.
Delusions may be triggered or worsened by stress, substance or alcohol abuse. Risk is slightly higher among socially isolated individuals, such as immigrants or those with sensory impairments (e.g., poor vision or hearing).

Though delusions can be a symptom of various mental health conditions, delusional disorder itself is relatively rare. It typically begins in middle age and is more commonly diagnosed in women.

Impact on Life

Delusional disorder may affect only one area of a person’s life. For example, someone with jealous delusions might experience severe marital conflict while continuing to function well in other domains.
However, in other cases, a person may develop multiple types of delusions, becoming increasingly consumed by them and unable to engage in normal social or occupational functioning.

In any case, life with delusional disorder can be filled with suffering and fear. Criticism or contradiction may be perceived as threatening or untrustworthy, making it difficult to form supportive relationships. As a result, many individuals live under chronic stress, which can worsen their symptoms and overall condition.

Without appropriate treatment, delusional disorder can lead to complications such as depression, social withdrawal, legal issues, self-harm, or harm to others.

Treatment

One of the biggest challenges in treating delusional disorder is that affected individuals often lack insight into their condition and are unlikely to seek help.
There is limited evidence supporting the long-term effectiveness of antipsychotic medication in delusional disorder. These medications are typically used only in the short term to manage acute or severe symptoms.
Hospitalization may be necessary if there is a risk of self-harm or harm to others.

Treatment usually focuses on managing co-occurring symptoms such as anxiety and depression with antidepressants or anxiolytics.

Research suggests that medication alone is less effective than combined treatment. The most effective approach is a combination of Cognitive Behavioral Therapy (CBT) and supportive psychotherapy. Family therapy may also be helpful. Individual therapy is generally more appropriate for delusional disorder than group therapy, which may not be well tolerated or effective.

With consistent treatment, the outlook is more favorable. Approximately 50% of individuals experience full recovery, while over 20% report significant symptom reduction.