Delusional disorder is a mental health condition where a person strongly believes something that isn’t true, even when there is clear evidence to the contrary. These beliefs can affect how a person thinks, behaves and interacts with others, and they can be difficult to recognize because they may seem realistic at first.
Tyler G. Jones, MD, a psychiatrist and chief medical officer at Banner Behavioral Health Hospital, explained that these disorders are relatively rare, affect men and women equally and typically strike during adulthood.
Types of delusional disorder
There are delusional disorders that are “non-bizarre,” meaning they could occur in real life, and “bizarre,” meaning they could not. Some examples of delusional disorders include:
- Erotomanic delusios:belief that someone is in love with you
- Grandiose: belief in exceptional abilities or importance
- Jealous: belief a partner is unfaithful
- Somatic: belief of a physical illness or defect
- Persecutory: belief of being harmed or targeted
Signs and symptoms of delusional disorder
The main symptom is the presence of delusion. This type of delusion can influence a person’s behavior. People with delusional disorders don’t see their beliefs as irrational or inaccurate even when others point this out. So, they don’t have a good sense of the problems created by their belief.
Depending on the type of delusion, they may be angry or violent. This behavior is more likely with people who feel persecuted or jealous. “Although their belief is not real, they behave in ways that would be understandable if their belief were true,” Dr. Jones said.
A person suffering from a delusional disorder may be socially isolated, distrustful or suspicious or have low self-esteem. They may feel exploited or be preoccupied with loyalty or trustworthiness. “Delusions are often based on misinterpretations of real events, and the person may overvalue particular ideas or read threatening or malicious intent into harmless or typical remarks or events,” Dr. Jones said.
Is delusional disorder dangerous?
Most people with delusional disorder are not violent, but certain types, especially persecutory or jealous delusions, may increase the risk of harmful behavior in some cases.
What causes delusional disorder?
Most of the time, we don’t know exactly what causes delusional disorders. Genetics may play a role since people who have family members with delusional disorders or schizophrenia have a higher risk of developing it. Living with a person who has a delusional disorder can cause a delusional disorder.
Substance use or misuse can play a role, and social isolation, low self-esteem or a high degree of envy could predispose someone to misinterpret ideas which can lead to delusional thinking.
Groups that are at increased risk because of isolation include people with significant hearing loss or a visual impairment, immigrants who may be isolated due to language barriers and seniors.
How is delusional disorder diagnosed?
Psychiatrists and psychologists usually diagnose these disorders. There’s no test for them, but bloodwork and imaging exams such as CT scans and MRI can rule out other possible causes. To assess for these disorders, a physician will ask questions about the person’s ideas and when they began, perform a full mental status exam and, with the person’s consent, interview family members for more details and information.
How to help someone with delusional disorder
The most important thing you can do for someone who may have a delusional disorder is to provide support and encourage them to seek a psychiatric evaluation. A positive, encouraging and supportive approach is more effective since they do not believe their thoughts are unusual. “They may also already feel persecuted or criticized, and a positive approach is less likely to cause more stress,” Dr. Jones said.
Friends and family members often experience their own stress, isolation, depression, frustration and grief in dealing with or living with someone with a delusional disorder. If that’s the case for you, it’s crucial to take care of your own mental health and seek help through your primary care provider, a therapist or a psychiatrist.
If you think you might be the object of someone’s delusional disorder, you may need to call the police. For example, if you have a neighbor who accuses you of things that aren’t true, such as spying, playing loud music, causing the wires to hum in their house or stealing, it is important to report these incidents to the police and possibly request protective services. “Although most people with serious mental illness are not violent, a smaller portion of people have committed crimes as a result of their delusions,” Dr. Jones said.
Can delusional disorder be treated?
People won’t understand that their ideas are delusional without proper treatment. Doctors generally recommend a combination of antipsychotic medications and cognitive behavioral therapy (CBT) for psychosis. CBT is a structured, goal-oriented therapy focused on unlearning negative thoughts and behaviors.
Untreated delusional disorders can lead to depression, harm to others and legal issues if the person stalks, harasses or harms the person involved in the delusion. For example, a person who believes a neighbor is spying on them may harass the neighbor to get them to stop the imagined offending behavior. “When a person’s delusions are not validated (because they are untrue), they may feel they have no other recourse but to harm the target of their belief,” Dr. Jones said.
If you’re a family member of someone who has a delusional disorder, you might want to seek counseling. “Family members should also consider treatment to gain education, support and guidance for themselves and the person with delusional disorder,” Dr. Jones said.
Frequently asked questions about delusional disorder
What is delusional disorder?
It is a mental health condition where a person believes something that is not true despite evidence.
What causes delusional disorder?
It may be linked to genetics, brain chemistry and environmental factors.
Can delusional disorder be treated?
Yes, treatment often includes medication and therapy.
Is delusional disorder the same as schizophrenia?
No, it is a different condition, though both involve psychosis.
The bottom line
Delusional disorder is a rare but serious mental health condition that can affect how a person thinks and behaves. With proper treatment and support, many people can manage symptoms.
Need help diagnosing or treating a delusional disorder?
Call Banner Behavioral Health at 602-254-4357.
Other useful articles
- What Can Happen When You Have Borderline Personality Disorder
- Does My Child Have Oppositional Defiant Disorder?
- Think the World Is Out to Get You? It Could Be Victim Mentality
- You Think You're Venting, but You Might Be Trauma Dumping
Content in this article was updated on April 15, 2026.
