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Delusional disorder: definition, causes, symptoms, types, and treatments

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Delusional disorder definition, causes, symptoms, types, and treatments

Delusional disorder is a psychotic disorder that causes an individual to have difficulty distinguishing what’s real from what’s imaginary. As its name suggests, the key feature of delusional disorder is the presence of one or more delusions, which are unusual beliefs held with strong conviction despite evidence that they are not true.

The causes of delusional disorder include a combination of genetic, biological, environmental, and psychological factors.

Delusional disorder symptoms are a sense of being taken advantage of, concern about the loyalty or reliability of friends, a propensity to infer danger from neutral statements or occurrences, carrying grudges all the time, and being prepared to react and respond to perceived slights.

The different types of delusional disorder include the erotomanic, jealous, grandiose, somatic, persecutory, and mixed.

The treatment for delusional disorder involves a combination of psychotherapy and medications, as the condition is highly resistant to treatment with only medication, according to an article entitled “Delusional Disorder” published under Cleveland Clinic.

What is delusional disorder?

Delusional disorder is a mental health condition that is characterized by holding onto non-bizarre delusional thoughts. Non-bizarre delusions are situations that aren’t real but can also possibly happen in real life, such as being manipulated, deceived, or having a cheating spouse.

German psychiatrist Emil Kraepelin first introduced delusional disorder in 1883. According to retired professor of psychiatry Alistair Munro’s book, Delusional Disorder: Paranoia and Related Illnesses, the condition was first termed paranoia, until it was renamed delusional disorder in the revised third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R).

How common is delusional disorder?

Delusional disorder is rare, and only affects around 0.05 to 0.1% of the general population – or approximately 24–30 cases per 100,000 individuals – according to the DSM-5. These numbers, however, are believed to be underestimations, because many people with delusional disorder do not regard it as an illness and therefore do not seek treatment.

Age of onset ranges from 18–90 years, with a mean age of about 40 years. That said, there is little to no information on the prevalence of the condition in children and adolescents. However, according to a 2012 systematic review and meta-analysis of population-based studies on the prevalence of psychotic symptoms in childhood and adolescence, the median prevalence of psychotic symptoms – including delusions – was 17% among children aged 9–12 years.

Moreover, according to the same study, psychotic symptom prevalence among teens aged 13–18 years was at 7.5%.

Delusional disorder is slightly more common in women than in men, with a female-to-male ratio of approximately 2 to 1. Women are also more likely than men to develop erotomanic delusions, while men are more likely than women to develop the persecutory and jealous types of delusion, as claimed by the continuing education activity by authors Shawn M. Joseph and Waquar Siddiqui on Delusional Disorder published in StatPearls.

Lastly, based on the results of a 1998 MRC-ALPHA study published in Schizophrenia Bulletin, the prevalence of delusional disorder in elderly people was found to be 0.04%, while the yearly incidence of new and relapsed cases was around 16 per 100,000 population.

What are the causes of delusional disorder?

hands painted with neon light in a dark room

The causes of delusional disorder are still poorly understood to this day. However, it is thought that a combination of factors play a role in the development of the condition. The causes of delusional disorder are listed below.

1. Genetic factors

Genetic factors refer to individual genes or a group of genes that influence the development of illnesses or diseases in humans. According to an article entitled “Delusions and Delusional Disorder” published in WebMD, there is a possibility that delusional disorder may be passed down from one’s parents due to the fact that the condition is more common in people who have blood relatives with delusional disorder or schizophrenia.

2. Biological factors

Biological factors are physical, physiological, neurological, or chemical influences that can cause a psychological effect. Structural and functional brain changes, including abnormal brain regions and brain chemical imbalance, are thought to play a role in the development of delusional symptoms. This is because these abnormalities are associated with parts of the brain that regulate thinking and perception.

3. Environmental and psychological factors

Environmental factors refer to exposure to substances, behaviors, or life stressors that increase a person’s risk of health problems or illnesses. On the other hand, psychological factors pertain to the elements of one’s personality that either limit or enhance the way they think, as asserted by a study guide for the Victorian Certificate of Education (VCE) Psychology Exam published in Study.com. Environmental factors that can lead to the development of delusional disorder include substance use, childhood trauma, recent immigration status, and urbanicity. Social isolation, low self-esteem, and distrust are also psychological factors that play a role in the onset of delusional symptoms.

What are the symptoms of delusional disorder?

The symptoms of delusional disorder are often non-bizarre, or delusions that are not entirely unrealistic and could possibly happen in real life. The symptoms of delusional disorder are listed below.

1. Sense of being taken advantage of

A sense of being taken advantage of means that a person feels as if their weaknesses are being used against them and for the other person’s own benefit. Among the different types of delusions, this symptom is associated with persecutory delusions.

This symptom can also cause excessive worry, and therefore can result in physical effects, such as irritability, inability to concentrate, nervous energy, sweating, and headaches. Behavioral effects of being taken advantage of include anxiety, trauma, depression, difficulty trusting others, and inability to form or maintain new relationships.

2. Concern about the loyalty or reliability of friends

Being concerned about the loyalty or reliability of friends refers to a negative feeling that your friends may not be genuine to you as you think. Needless to say, doubting the loyalty or reliability of your friends without having any proof can cause you to worry excessively and even push them away, which can lead to a lack of supportive network.

Physical effects may include high blood pressure, fatigue, rapid breathing, trembling, and an unhealthy body mass index (BMI). On the other hand, the behavioral effects of being concerned about the loyalty of friends are social isolation, lower self-esteem, anxiety, and a pessimistic outlook in life.

3. A Propensity to infer danger from neutral statements or occurrences

Inferring danger from rather neutral statements or occurrences means that the afflicted person misinterprets pleasant or kind remarks as having hidden belittling or dangerous meaning.

Being constantly suspicious of others can have negative physical effects, including irritability, anger outbursts, and hypervigilance. Behavioral effects include social isolation, aggression, avoiding intimacy, and referential thinking.

4. Carrying grudges all the time

Bearing grudges all the time refers to one persecutory delusional disorder symptom in which an individual tends to dwell more on resentments or anger compared to other people.

The physical effects of carrying grudges include anger, higher stress levels, heart problems, high blood pressure, lowered immunity, and inflammation. On the other hand, behavioral effects may include aggressive behavior, anxiety, depression, and emotional dysregulation.

5. Being prepared to react and respond to perceived slights

One of the more common delusional symptoms is the tendency to overreact to perceived slights, where an individual has an inappropriate emotional response, which is often out of proportion to what provoked it.

Physical effects of overreacting to perceived slights include anger or explosive outbursts, headaches, upset stomach, changes in sleep patterns, and hypervigilance.

On the other hand, behavioral effects of responding inappropriately to perceived slights include aggressive behavior, difficulty making connections, anxiety, depression, and suicidal thoughts or behaviors.

What are the types of delusional disorder?

The most commonly encountered types of delusions are based on the main delusional themes that an individual experiences. The types of delusional disorder are listed below.

1. Erotomanic

Erotomanic delusions are unfounded beliefs that someone who is of higher status is in love with the afflicted person. Causes of erotomania include genetics, extreme stress, trauma, low self-esteem, difficulty with socialization cues, and even social media usage.

The symptoms of erotomania are obsessive thoughts about the perceived love interest who is a person of power or stranger, persistent efforts to contact the person through letter-writing, stalking, or showing up at their home, and believing that the object of their obsession is sending them secret messages to express their affection, even when they have no reason to believe so.

The effects of erotomanic delusions include stalker-like behaviors, aggression, violence, problems with the law, and even death of either person involved. Erotomania is different from other subcategories of delusions in that it is the first one to be implicated in what is possibly the first reported case in a study on delusional disorder, erotomanic type, exacerbated by social media use published in Case Reports in Psychiatry about a delusional disorder sufferer who used social media to support his stalking behavior. Compared to other types of delusions, erotomanic ones are also much rarer.

2. Jealous

Jealous delusions refer to a form of delusional disorder that involves beliefs that one’s intimate partner is or has been unfaithful, even without objective evidence. The causes of delusional jealousy include low self-esteem, insecurity, brain injuries or disorders, reduced sexual function, and co-occurring mental health disorders, such as anxiety disorders, substance use disorders, or schizophrenia.

Symptoms that may indicate the presence of jealous delusions include hypervigilance, excessively questioning a partner’s behaviors, trying to confine a partner to their home in an attempt to limit their outdoor activities, showing up unannounced at a partner’s workplace or other locations to catch them in the act of infidelity, and isolating the victim from family and friends for them to become dependent on the controlling partner.

The effects of having the jealous type of delusion are aggression, violence, confirmatory behaviors, domestic abuse, and suicidal thoughts. The key difference of delusional jealousy from other types of delusions is that it is the subcategory that is most associated with intimate partner violence (IPV), as stated in chapter 11 of the book Applied Crime Analysis by Grant C.B. Sinnamon. Moreover, compared to other forms of delusions, jealousy is most commonly linked to criminal behavior.

3. Grandiose

Grandiose delusions are an exaggerated sense of one’s own importance, self-worth, talent, power, intelligence, or identity. Delusions of grandeur are often caused by traumatic life experiences, brain chemical imbalance, social isolation, high levels of stress, brain injury, and neurological conditions, such as Parkinson’s disease or dementia.

Symptoms that may indicate the presence of grandiose delusions include a false belief of one’s own greatness, difficulties getting along with people due to their delusions, responding with anger when someone contradicts their delusional beliefs, and convincing others to accept their delusions.

The effects of having delusions of grandeur include impaired judgment, strained relationships at home or at work, job loss, and depression. The difference of grandiose delusions from other types of delusions is that sufferers describe these unfounded beliefs as very important to them, because such self-concepts provide them with a sense of purpose and belonging, as reported in a qualitative study on understanding, treating, and renaming grandiose delusions published in the Wiley Online Library. Compared to other subcategories, delusions of grandeur are also most commonly linked to bipolar disorder and narcissistic personality.

4. Somatic

Somatic delusions are false beliefs that there is something medically, biologically, or physically wrong with the person experiencing the delusions. The development of somatic delusions may be influenced by different factors, including genetics, brain chemical imbalance, emotional dysregulation, and reduced blood flow to the brain.

Symptoms that indicate the presence of a somatic type delusional disorder include excessive thoughts about the potential illness, interpreting normal physical sensations as signs of a severe condition, feeling that any medical examination or testing have been inadequate, and frequently checking one’s body for signs of abnormalities or illnesses.

The effects of somatic delusions include self-harm, social avoidance, isolation, depression, poor quality of life, and a greater risk for suicide. The difference of somatic delusion from other subcategories of delusions is that it can trigger physical symptoms. Furthermore, a 2018 case report entitled “Violence Associated With Somatic Delusions” suggests that compared to other types, suicidal thoughts and suicidal attempts are also more frequently seen in somatic delusions.

5. Persecutory

Unfounded beliefs that other people or groups intend to harm or mistreat the affected person in some manner are referred to as persecutory delusions. It is widely believed that this type of delusion may be caused by genetics, structural and functional brain abnormalities, childhood trauma and neglect, emotional abuse, and various mental illnesses, such as schizophrenia, bipolar disorder, or major depressive disorder.

The symptoms of persecutory delusions include excessive worry about impending harm, extreme paranoia, fearing everyday situations, and reporting concerns to legal authorities, despite the assumed threat being unproven or impossible.

The effects of having persecutory delusions include anger outbursts, violent behavior, agitation, aggression, and being unreasonably prone to engage in lawsuits. The persecutory type of delusion is different from other types in that it is the most common one experienced by sufferers of a delusional mental illness. Compared to other subtypes, persecutory delusions are also the most likely to be acted upon, causing patients to be at risk of harming themselves or other people.

6. Mixed

Mixed delusions refer to experiencing one or more types of delusion. The causes of mixed delusions include genetics, abnormalities in the brain, trauma, and extreme stress. Someone with mixed delusions may experience a combination of the symptoms of the delusional themes listed above.

The effects of this type of delusional disorder include anxiety, depression, social isolation, reduced quality of life, and suicidal thoughts. The difference of mixed delusions from other types of delusional disorder is that it is more complex due to the existence of two or more delusional themes. Compared to other subcategories, it is also the only type of delusion where no single theme is prevalent, but rather it is a mix of two or more subtypes.

Who is affected by delusional disorder?

Delusional disorder often affects individuals in middle or late adulthood. The condition is also said to be more slightly common in women. However, according to Howard M. Fillit, MD, one of the authors of Brocklehurst’s Textbook of Geriatric Medicine and Gerontology, men tend to have an earlier onset of symptoms than women (40 to 49 years vs. 60 to 69 years).

What are the risk factors for delusional disorder?

There are certain factors that can contribute to an increased likelihood of developing delusions. The risk factors for delusional disorder are listed below.

  • A family history of delusional disorder or schizophrenia: Having blood relatives with delusional disorder or schizophrenia makes someone more susceptible to experiencing delusions. This indicates a potential genetic risk factor for the disorder.
  • Advanced age: A hypothesis-driven review of recent work focusing on epidemiology, clinical aspects, and outcomes of delusional disorder in old age published in the International Journal of Environmental Research and Public Health suggests that delusional disorder becomes more prevalent in old age, especially in women.
  • Sensory impairment: Sensory impediments, such as visual or hearing impairments, can increase someone’s risk of having delusions. Based on the results from the DeliraAnda case register on the comorbidity between delusional disorder and sensory deficits published in European Psychiatry, one explanation is that these conditions can lead to misinterpretations of the environment, causing predisposed people to develop delusional disorder.
  • Social isolation: Feelings of loneliness and social isolation have recently been reported to play a causal role in the development of psychotic symptoms – one of them being delusions – as stated by a meta-analytical review on loneliness in psychosis published in the Schizophrenia Bulletin.
  • Immigration: Mounting evidence proposes that immigrant populations are at an increased risk of developing delusional disorder. Some explanations proposed to this date include racism or social defeat, changes in sun exposure, changes in diet, and stress related to immigration, as stated by Marie-Jose Dealberto from the Department of Psychiatry at the Ottawa Hospital and University of Ottawa in her study published in Medical Hypotheses.

How is delusional disorder diagnosed?

strobe lights

Delusional disorder is diagnosed by using the DSM-5 criteria for the condition, which includes the criterion that the patient has to have one or more delusions for one month or longer that can’t be explained by other medical conditions.

To rule out other health conditions or medications that may be causing delusions, the doctor may use laboratory tests and screening for alcohol and drugs. After other possible causes have been ruled out, the affected person may be referred to a mental health professional.

The mental health professional will then check the mental status of the patient by asking about their thoughts, feelings, moods, or delusions with the help of psychiatric assessment tools.

How to prevent delusional disorder?

There is unfortunately no proven way to prevent delusional disorder. However, early detection and intervention can make a significant difference to the quality of life of the patient.

Early identification and accurate diagnosis of the disorder lead to effective treatment and management of delusional disorder symptoms, thus reducing the disruption to the person’s daily functioning, ability to relate to others, and personal relationships.

What are the treatments for delusional disorder?

The treatments for delusional disorder often involve a combination of psychotherapy and medications. The treatments for delusional disorder are listed below.

  • Individual psychotherapy: According to The American Psychiatric Association Publishing Textbook of Psychiatry, individual psychotherapy is more ideal for patients with delusional disorder compared to group psychotherapy because they are often quite suspicious and sensitive. This type of therapy has an average of 15 to 20 sessions, lasting from 45 to 60 minutes each. Because the goal of individual psychotherapy is to establish a therapeutic alliance between the therapist and the patient, it helps develop positive feelings, such as self-esteem and compassion, in individuals with delusional disorder.
  • Cognitive behavioral therapy (CBT): Cognitive behavioral therapy helps with delusional disorder by enhancing function despite difficult experiences such as delusions. The course of CBT treatment typically lasts for between 6 and 20 sessions, with each session lasting 30 to 60 minutes, according to an overview of cognitive behavioural therapy (CBT) published in the National Health Service website. CBT is a research-proven treatment method for people suffering from any of the subtypes of delusional disorder because it seeks to identify and change unhelpful thought patterns, negative core beliefs, and behaviors.
  • Family therapy: Family therapy helps individuals with delusional disorder by involving their loved ones in the recovery process. It often includes psychoeducation, which increases the patient and their family members’ knowledge about the condition as well as their coping strategies. Family therapy is usually short-term and only lasts for about 12 sessions. It is, however, very effective in the treatment of delusional disorder because family intervention improves a patient’s social functioning and the chances of relapse.
  • Medications: Antipsychotic drugs help reduce delusions by altering brain chemistry. Both first- and second-generation antipsychotics may be used as delusional medication for patients. Due to their ability to block neurotransmitters that play a role in the development of delusions, antipsychotic medications are effective in reducing or relieving symptoms of delusional disorder. However, according to an article entitled, “Treating Delusional Disorder: What Are My Options?” published in PsychCentral, therapy in conjunction with antipsychotics remains the most effective form of treatment for the condition.

Does delusional disorder have a cure?

No, delusional disorder does not have a cure. The condition is also frequently lifelong and is considered difficult to treat. However, delusional disorder is now regarded as a treatable condition with the help of recent advances in its treatment, according to Theo C. Manschrek and Nealia L. Khan in their study entitled, “Recent advances in the treatment of delusional disorder”.

Management of symptoms is possible through the combination of therapy and medication, making it possible for patients to obtain relief from delusional thinking and to live a fuller life with support from family and friends as well.

What is the difference between delusional disorder and schizophrenia?

a confused girl

The difference between delusional disorder and schizophrenia mainly lies in the symptoms. Delusional disorder only has delusions as its symptom, while schizophrenia, aside from the presence of delusions, other symptoms, such as hallucinations, cognitive deficits, thought disorder, apathy, and social isolation, are also evident, according to a mini narrative review on the differences between delusional disorder and schizophrenia published in the World Journal of Psychiatry.

Furthermore, when considering delusional disorder vs. schizophrenia, another key difference is the functionality of the affected individual. Most people with delusional disorder can usually function normally in everyday life, while the ability to perform daily activities is often impaired in schizophrenic patients.