Delusional Disorder

What is Delusional Disorder?

Delusional Disorder is a serious mental health disorder where a person cannot tell the difference between what is real and what is imagined. The hallmark trait of delusional disorder is a strong belief in or about something that does not align with reality. The belief is either entirely untrue or it is an extreme exaggeration of the truth. Often, these beliefs are based on an ongoing misinterpretation of perceptions or experiences. 

Examples of delusions are paranoia that you’re being followed or watched, a belief that someone is infatuated or in love with you from a distance, a fear that you are being poisoned, plotted against, or deceived. People with delusional disorder have non-bizarre delusions, meaning the delusions are plausible enough and could occur in real life.

People with delusional disorder tend to function and socialize normally in their daily lives, apart from their delusions. On occasion, if the person becomes preoccupied by the delusion, it may disrupt normal daily functioning. Typically, people with delusional disorder do not exhibit odd or bizarre behavior. This is not the case for people with psychotic disorders or schizophrenia, which may also have delusions as a symptom. Delusional disorder is somewhat rare and tends to be diagnosed in people who are middle aged or late in life. 

Types of Delusional Disorders

  • Erotomanic. A person believes someone, usually famous or important, is in love with him or her. Contact of this person may be attempted, and stalking is common to this delusion.
  • Grandiose. A person has an over-inflated sense of worth, power, knowledge, and importance, to the point of believing they have a great talent or made an important discovery.
  • Jealous. A person believes that their spouse or partner is being unfaithful or cheating on them.
  • Persecutory. A person believes that they (or someone close to them) are being mistreated or conspired against. They believe someone is spying on them or planning to harm them. With this delusion, a person may file many legal complaints.
  • Somatic. With this delusion, a person believes that they have a medical problem or physical defect.
  • Mixed. A person has more than one of the delusions listed above.


There are several symptoms that may occur with delusional disorder. Symptoms include:

  • The presence of 1 or more non-bizarre delusion for 1 month or more
  • Criterion for schizophrenia has never been met, and if hallucinations are present, they are not prominent and only related to the delusional theme
  • Level of functioning is not significantly impaired, and delusions and behaviors are not bizarre or odd
  • Manic or major depressive episodes have been brief in comparison to the length of the delusional period
  • Angry, irritable, or depressed mood

Cause and Risk Factors

The cause of delusional disorder is unknown. Current research is studying how genetics, biological, psychological, and environmental factors may contribute to the development of delusional disorder. There are certain risk factors that seem to increase the likelihood of developing delusional disorder. Those risk factors include:

  • Genetic. There seems to be more of a likelihood to develop delusional disorder when there is a family history of delusional disorder or schizophrenia, which indicates a potential genetic factor.
  • Biological. Atypical brain regions that manage perception and thinking may contribute to delusional symptoms.
  • Psychological. People who suffer from social isolation, substance abuse, or significant stress may trigger symptoms of delusional disorder. 


If delusional disorder is suspected, a doctor will take a thorough medical history and perform a physical exam. It may also be recommended to order blood work and other diagnostic tests to rule out any medical conditions. If the doctor determines that no medical condition exists, a referral to a psychiatrist or psychologist may be made.

A mental health professional will do a thorough intake and may choose to administer various assessments to determine whether criteria is met for delusional disorder. A diagnosis would be based on the appropriate diagnostic criteria being met, and this information would be gathered over the course of several sessions. According to the American Psychiatric Association in the DSM-V, criteria for delusional disorder includes:

  • The presence of 1 or more delusions with a duration of 1 month or longer
  • Criteria has never been met for schizophrenia, and if hallucinations are present, they are not prominent and are only related to the subject of the delusion
  • Aside from the impact or ramifications of the delusion(s), daily functioning is not impaired and there are no odd or bizarre behaviors exhibited
  • Any manic or major depressive episodes that have occurred are brief in comparison to the delusional periods
  • The disturbance is not better explained by a medical condition, substance use, or another mental disorder (body dysmorphic disorder or obsessive-compulsive disorder)

Treatment and Recovery

There is no known prevention for delusional disorder. However, the earlier it is treated, the more likely someone is to recover or experience a reduction of symptoms. Delusional disorder is a chronic, ongoing issue. Recovery varies between individuals and is dependent on a person’s willingness to seek treatment and stick with it, life circumstances, and social supports. Some people experience a fully recovery, while others may have periods of remission and relapse.

Sometimes, people with mental disorders are not aware that they are unwell, which means many people with delusional disorder do not seek help. Treatment and recovery are more successful when there are multiple supports (including friends and family) and resources involved. Treatment typically consists of a combination of psychotherapy (counseling) and medication. Medication alone seems to only have partial success in recovery.


  • Individual therapy. Patients meet one on one with a mental health professional over time to work on identifying and addressing underlying issues, creating treatment goals, and working toward symptom reduction and recovery. 
  • Cognitive-behavioral therapy. This type of therapy seeks to identify, challenge, and replace distorted thinking, destructive thought patterns, and negative core beliefs.
  • Family therapy. The purpose of this therapy is to help families understand the disorder, learn boundaries, and learn how to support someone with delusional disorder.


Conventional antipsychotics (neuroleptics). These medications have been in existence since the 1950’s and work by blocking dopamine receptors in the brain. Studies have shown that dopamine may be the neurotransmitter responsible for delusions. Conventional antipsychotics include: 

  • chlorpromazine (Thorazine) 
  • fluphenazine (Prolixin) 
  • haloperidol (Haldol) 
  • thiothixene (Navane) 
  • trifluoperazine (Stelazine) 
  • perphenazine (Trilafon)
  • thioridazine (Mellaril)

Newer medications (atypical antipsychotic drugs). These newer drugs seem to be more effective at treating symptoms of delusional disorder. The drugs work to block both dopamine and serotonin receptors in the brain. Newer medications include:

  • risperidone (Risperdal)
  • clozapine (Clozaril)
  • quetiapine (Seroquel) 
  • ziprasidone (Geodon)
  • olanzapine (Zyprexa)

Other medications. Other medications that may be used to treat delusions are antidepressants (SSRI’s), or sedatives or tranquilizers if anxiety is severe or there is trouble with sleeping.

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