Delusional Disorder Causes & Effects

The signs, symptoms, and effects of delusional disorder can look different for each person impacted. Learning about delusional disorder is one of the first steps toward healing.

Understanding Delusional Disorder

Learn about delusional disorder

A delusion is a belief that a person holds that is not based in reality and is not altered or modified when the person is presented with contradictory evidence. As such, people who are suffering from delusional disorder struggle to align reality with their perceptions of reality. There are a number of different delusions that a person may hold. Some individuals believe that another person is in love with him or her (the erotomanic type), while other people believe that they possess a great hidden talent or have a history of great achievements (the grandiose type). Still other people become convinced that a lover or spouse has been unfaithful (the jealous type), or that one is being pursued, hunted, attacked, persecuted, or prevented from achieving goals (the persecutory type). Other people develop delusions about their bodies or bodily sensations, such as believing that insects are inside of them or that they have a foul odor, which would indicate that they are suffering from the somatic type of the disorder. Often a person with delusional disorder may behave in a relatively healthy, adaptive manner and only display odd behavior where his or her delusion is concerned. That being said, delusional disorder has the potential to create enormous upset and turmoil in a person’s life. Thankfully, there are treatment options available to help people manage the painful effects of delusion disorder.


Delusional disorder statistics

According to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, it is estimated that approximately 0.2 percent of people will suffer from delusional disorder at some point in their lives. Overall rates of delusional disorder are the same between men and women, though men are more likely to develop jealous-type delusions.

Causes and Risk Factors

Causes and risk factors for delusional disorder

Research suggests that people who have family members with schizophrenia or schizotypal personality disorder are at greater risk of developing delusional disorder, suggesting that genetics may play a causal role in determining a person’s risk of developing the disorder. In addition, people who are older are more likely than younger individuals to develop delusional disorder as well.

Risk Factors:

  • Family history of schizophrenia or schizotypal personality disorder
  • Being of older age

Signs and Symptoms

Signs and symptoms of delusional disorder

The signs and symptoms of delusional disorder differ primarily according to personality differences and the type of delusion with which a person is struggling. These symptoms also must not be due to consumption of a drug or other substance. Despite individual differences in the disorder, the following are some common signs and symptoms of delusional disorder:

Behavioral symptoms:

  • Antagonistic behavior, such as filing lawsuits or sending many letters of protest
  • Aggressive behavior towards others that is consistent with delusions
  • Other behaviors that are consistent with delusions, such as scratching one’s skin if one believes one’s body is infested with insects
  • Poor occupational functioning directly related to the delusional belief
  • Relative lack of impairment in functioning other than that caused by the delusion

Cognitive symptoms:

  • Experiencing a delusion or delusions
  • Poor insight into irrationality of one’s delusional belief(s)
  • Believing that others are attempting to harm the person (persecutory type)
  • Belief that others are in love with the person (erotomanic type)
  • Belief that one has great talents or a history of important achievements (grandiose type)
  • Believing that one’s spouse or significant other is unfaithful (jealous type)
  • Belief that one’s body has a foul odor, is malfunctioning or misshapen, or is infested (somatic type)
  • Other delusional belief (mixed or unspecified type)
  • Lack of bizarre or odd beliefs other than the delusion

Psychosocial symptoms:

  • Social difficulties related to one’s delusion(s)
  • Tension in romantic relationships related to the delusion(s)
  • Irritability


Effects of delusional disorder

Delusional disorders tend to have less of an effect on a person’s overall ability to function than other schizophrenia spectrum or psychotic disorders. However, if a person’s delusional beliefs come to the surface in multiple settings, the potential for negative effects is much greater. If delusional disorder is left untreated, the following are some potential negative consequences that a person may experience:

  • Disruption in social relationships
  • Social isolation
  • Tension with one’s spouse or significant other
  • Poor work performance
  • Loss of job
  • Financial difficulties
  • Onset or worsening of mental health symptoms
  • Irritability
  • Anger or violent behavior
  • Legal difficulties

I now am on the road to recovery because of the process groups and my personal therapist at Southcoast. Thank you for helping me get my life together. I am forever grateful!

– Anonymous Client
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