Delusional disorder overview

# Overview
Delusional disorder is a psychiatric condition in which the patients present with delusions, but with no accompanying prominent hallucinations, thought disorder, mood disorder, or significant flattening of affect. Delusions are a specific symptom of psychosis. Delusions can be bizarre or non-bizarre in content. Non-bizarre delusions are fixed false beliefs that involve situations that could potentially occur in real life, such as being followed, having an infection, being loved, and being deceived by one's spouse. Bizarre delusions are clearly improbable. Delusions that express a loss of control over mind or body are generally considered to be bizarre and include belief that alien thoughts have been put into one's mind, that ones thoughts have been removed by an outside force, or that ones body or actions are being acted on or manipulated by an outside force. Apart from their delusions, people with delusional disorder may continue to socialize and function in a normal manner and their behavior does not generally seem odd or bizarre. However, the preoccupation with delusional ideas can be disruptive to their overall lives. For the diagnosis to be made, auditory and visual hallucinations cannot be prominent, though olfactory or tactile hallucinations related to the content of the delusion may be present. Delusions are false beliefs based on incorrect assumption about external reality that persist despite the evidence to the contrary and these beliefs are not ordinarily accepted by other members of the person's culture. Delusional disorder may be classified according to Diagnostic and Statistical Manual based on content of the delusions into seven subtypes: erotomanic, grandiose, jealous, persecutory, somatic, mixed, and unspecified.  The exact pathogenesis of delusional disorder is not fully understood. It is thought that delusional disorder may be produced by polymorphisms in genes coding for dopamine receptors (DRD3 and DRD4). The cause of delusional disorder has not been identified. Genetic, biochemical, psychological, and environmental factors may play a significant role in the development of delusional disorder. Delusional disorder must be differentiated from other diseases that cause delusions, such as substrate deficiency, neurodegenerative disorders, vascular disease, other CNS disorders, infectious diseases, vitamin deficiencies, metabolic disorders, endocrinopathies, medications, toxins, substances, and other mental disorders such as schizophrenia and mood disorders. The incidence of delusional disorders is approximately 0.7 to 3.0 cases per 100, 000 individuals annually. The prevalence of delusional disorders is approximately 24 to 30 cases per 100, 000 individuals annually. Females are more commonly affected with delusional disorder than males. The diagnosis of delusional disorder is based on the DSM-5 diagnostic criteria, which include criterion A i.e the presence of one (or more) delusions with a duration of one month or longer, criterion B i.e criterion A for schizophrenia has never been met, criterion C i.e apart from the impact of the delusion(s) or its ramifications, functioning is not markedly impaired, and behavior is not obviously bizarre or odd, criterion D i.e if manic or major depressive episodes have occurred, these have been brief relative to the duration of the delusional periods, and criterion E i.e the disturbance is not attributable to the physiological effects of a substance or another medical condition and is not better explained by another mental disorder, such as body dysmorphic disorder or obsessive-compulsive disorder. The optimal therapy for delusional disorder includes pharmacotherapy, cognitive-behavioral therapy, supportive psychotherapy, involuntary treatment, and insight oriented therapy.

# Historical Perspective
Delusional disorder was first introduced by Emil Kraepelin, a German Psychiatrist, in the year 1883. In the year 1977 Winokur redescribed paranoia under the name of delusional disorder. In the year 1987 delusional disorder was introduced in DSM-III-R and continued to be present in subsequent editions.

# Classification
Delusional disorder may be classified according to Diagnostic and Statistical Manual based on content of the delusions into seven subtypes: erotomanic, grandiose, jealous, persecutory, somatic, mixed, and unspecified.

# Pathophysiology
The exact pathogenesis of delusional disorder is not fully understood. It is thought that delusional disorder may be produced by polymorphisms in genes coding for dopamine receptors (DRD3 and DRD4).

# Causes
The cause of delusional disorder has not been identified. Genetic, biochemical, psychological, and environmental factors may play a significant role in the development of delusional disorder.

# Differential Diagnosis
Delusional disorder must be differentiated from other diseases that cause delusions, such as substrate deficiency, neurodegenerative disorders, vascular disease, other CNS disorders, infectious diseases, vitamin deficiencies, metabolic disorders, endocrinopathies, medications, toxins, substances, and other mental disorders such as schizophrenia and mood disorders.

# Epidemiology and Demographics
The incidence of delusional disorders is approximately 0.7 to 3.0 cases per 100, 000 individuals annually. The prevalence of delusional disorders is approximately 24 to 30 cases per 100, 000 individuals annually. Females are more commonly affected with delusional disorder than males.

# Comorbid Conditions
Common comorbid conditions associated with delusional disorder include depression and anxiety.

# Risk Factors
Common risk factors in the development of delusional disorder are family history of paranoid personality disorder, sensory impairment, middle age (18-40 years), social isolation, personality (sensitivity; narcissistic traits), immigration, and low socioeconomic status.

# Screening
According to the United States Preventive Services Task Force, screening for delusional disorder is not recommended.

# Natural History, Complications and Prognosis
If left untreated, delusional disorder may progress to develop life-long illness. Common complications of delusional disorder include depression, violence and legal problems, and isolation. The prognosis for people with delusional disorder varies depending on the type of delusional disorder, on the person, and the person's life circumstances, including the availability of support and a willingness to adhere with treatment.

# Diagnostic Criteria
The diagnosis of delusional disorder is based on the DSM-5 diagnostic criteria, which include 5 citeria:
- Criterion A: Presence of one (or more) delusions with a duration of one month or longer
- Criterion B: Diagnostic criteria for schizophrenia have not been met
- Criterion C: Apart from the impact of the delusion(s) or its ramifications, functioning is not markedly impaired, and behavior is not obviously bizarre or odd,
- Criterion D: If manic or major depressive episodes have occurred, these have been brief relative to the duration of the delusional periods
- Criterion E: The disturbance is not attributable to the physiological effects of a substance or another medical condition and is not better explained by another mental disorder, such as body dysmorphic disorder or obsessive-compulsive disorder

# History and Symptoms
The hallmark of delusional disorder is non-bizarre delusions. A positive history of self-reference, aggressiveness, irritable, angry, or low mood and hallucinations that are related  to the delusion is suggestive of delusional disorder.

# Physical Examination
Patients with delusional disorder usually appear well groomed and well-dressed without evidence of gross impairment. Mental status examination of patients with delusional disorder is usually remarkable for dysphoria, delusional beliefs, and suicidal or violent thinking.

# Laboratory Findings
There are no diagnostic lab findings associated with delusional disorder.

# Chest-X Ray
There are no chest-x ray findings associated with delusional disorder.

# CT
There are no CT findings associated with delusional disorder.

# MRI
On MRI, delusional disorder is characterized by greater lateral ventricle volume and hyper intense MRI signals in deep white matter in temporal and frontal lobes.

# Other Imaging Findings
There are no other imaging findings associated with delusional disorder.

# Other Diagnostic Studies
There are no other diagnostic studies associated with delusional disorder.

# Medical Therapy
The optimal therapy for delusional disorder includes pharmacotherapy, cognitive-behavioral therapy, supportive psychotherapy, involuntary treatment, and insight oriented therapy.

# Primary Prevention
There are no primary preventive measures available for delusional disorder.

# Secondary Prevention
There are no secondary preventive measures available for delusional disorder.