Delusional disorder is a mental disorder in which a person has delusions, but with no accompanying prominent hallucinations, thought disorder, mood disorder, or significant flattening of affect.American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders, (5th ed., text revision). Washington, DC: American Psychiatric Association. 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 occur in real life, such as being harmed or poisoned.Hales E and Yudofsky JA, eds, The American Psychiatric Press Textbook of Psychiatry, Washington, DC: American Psychiatric Publishing, Inc., 2003 Apart from their delusion or delusions, people with delusional disorder may continue to socialize and function in a normal manner and their behavior may not necessarily seem odd.Winokur, George."Comprehensive Psychiatry-Delusional Disorder"American Psychiatric Association. 1977. p 513 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. The delusions cannot be due to the effects of a drug, medication, or general medical condition, and delusional disorder cannot be diagnosed in an individual previously properly diagnosed with schizophrenia. A person with delusional disorder may be high-functioning in daily life as measured, for example, by the Global Assessment of Functioning. Recent and comprehensive meta-analyses of scientific studies point to an association with a deterioration in aspects of IQ in psychotic patients, in particular, perceptual reasoning, although the between-group differences were small.
According to German psychiatrist Emil Kraepelin, patients with delusional disorder remain coherent, sensible, and reasonable. The Diagnostic and Statistical Manual of Mental Disorders (DSM) defines six subtypes of the disorder: erotomanic (belief that someone is in love with one), grandiose (belief that one is the greatest, strongest, fastest, richest, or most intelligent person ever), jealous (belief that one is being cheated on), persecutory (delusions that one or more people are treating the person with the disorder in a malevolent or harmful way), somatic (belief that one has a disease or medical condition), and mixed (i.e., having features of more than one subtype). Delusions also occur as symptoms of many other mental disorders, especially the other psychotic disorders.
The DSM-IV and psychologists agree that personal beliefs should be evaluated with great respect to cultural and religious differences, as some cultures have normalized beliefs that may be considered delusional in other cultures.
An earlier, now-obsolete, nosological name for delusional disorder was "paranoia". This should not be confused with the modern definition of paranoia (i.e., persecutory ideation specifically).
Classification The International Classification of Diseases classifies delusional disorder as a mental and behavioural disorder.Drs; Diagnosis of a specific type of delusional disorder can sometimes be made based on the content of the delusions, to wit, the Diagnostic and Statistical Manual of Mental Disorders (DSM) enumerates seven types: Erotomanic type (erotomania): delusion that another person, often a prominent figure, is in love with the individual. The individual may breach the law as they try to obsessively make contact with the desired person. Grandiose type (megalomania): delusion of inflated worth, power, knowledge, identity or believing oneself to be a famous person, claiming the actual person is an impostor or an impersonator. Jealous type: delusion that the individual's sexual partner is unfaithful when it is untrue. The patient may follow the partner, check text messages, emails, phone calls etc. in an attempt to find "evidence" of the infidelity. Persecutory type: This delusion is a common subtype. It includes the belief that the person (or someone to whom the person is close) is being malevolently treated in some way. The patient may believe that they have been drugged, spied upon, harmed, harassed and so on and may seek "justice" by making reports, taking action or even acting violently. Somatic type: delusions that the person has some physical defect or general medical condition Mixed type: delusions with characteristics of more than one of the above types but with no one theme predominating. Unspecified type: delusions that cannot be clearly determined or characterized in any of the categories in the specific types.http://www.health.am/psy/delusional-disorder Delusional Disorder. Retrieved 7 August 2012
Signs and symptoms
The following can indicate a delusion: An individual expresses an idea or belief with unusual persistence or force, even when evidence suggests the contrary. That idea appears to have an undue influence on the person's life, and the way of life is often altered to an inexplicable extent. Despite their profound conviction, there is often a quality of secretiveness or suspicion when the person is questioned about it. The individual tends to be humorless and oversensitive, especially about the belief. There is a quality of centrality: no matter how unlikely it is that these strange things are happening to the person, they accept them relatively unquestioningly. An attempt to contradict the belief is likely to arouse an inappropriately strong emotional reaction, often with irritability and hostility. They will not accept any other opinions. The belief is, at the least, unlikely, and out of keeping with the individual's social, cultural, and religious background. The person is emotionally over-invested in the idea and it overwhelms other elements of their psyche. The delusion, if acted out, often leads to behaviors which are abnormal, and out of character, although perhaps understandable in light of the delusional beliefs. Other people who know the individual observe that the belief and behavior are uncharacteristic and alien.
Additional characteristic of delusional disorder include the following: It is a primary disorder. It is a stable disorder characterized by the presence of delusions to which the patient clings with extraordinary tenacity. The illness is chronic and frequently lifelong. The delusions are logically constructed and internally consistent. The delusions do not interfere with general logical reasoning (although within the delusional system the logic is perverted) and there is usually no general disturbance of behavior. If disturbed behavior does occur, it is directly related to the delusional beliefs. The individual experiences a heightened sense of self-reference. Events which, to others, are nonsignificant are of enormous significance to them, and the atmosphere surrounding the delusions is highly charged.
However, this should not be confused with gaslighting, where a person denies the truth, and causes the one being gaslit to think that they are being delusional.
Causes
The cause of delusional disorder is unknown, but genetic, biochemical, and environmental factors may play a significant role in its development. Some people with delusional disorders may have an imbalance in neurotransmitters, the chemicals that send and receive messages to the brain.Kay DWK. "Assessment of familial risks in the functional psychoses and their application in genetic counseling. Br J Pschychiatry." 1978. p385-390 There does seem to be some familial component, and immigration (generally for persecutory reasons), drug abuse, excessive stress,Karakus, Gonca."Delusional Parasitosis: Clinical Features, Diagnosis and Treatment"American Psychiatric Association. 2010.p396 being married, being employed, low socioeconomic status, celibacy among men, and widowhood among women may also be risk factors. Delusional disorder is currently thought to be on the same spectrum or dimension as schizophrenia, but people with delusional disorder, in general, may have less symptomatology and functional disability.
Diagnosis
Differential diagnosis includes ruling out other causes such as drug-induced conditions, dementia, infections, metabolic disorders, and endocrine disorders. Other psychiatric disorders must then be ruled out. In delusional disorder, mood symptoms tend to be brief or absent, and unlike schizophrenia, delusions are non-bizarre and hallucinations are minimal or absent.
Interviews are important tools to obtain information about the patient's life situation and history to help make a diagnosis. Clinicians generally review earlier medical records to gather a full history. Clinicians also try to interview the patient's immediate family, as this can be helpful in determining the presence of delusions. The mental status examination is used to assess the patient's current mental condition.
A psychological questionnaire used in the diagnosis of the delusional disorder is the Peters Delusion Inventory (PDI) which focuses on identifying and understanding delusional thinking. However, this questionnaire is more likely used in research than in clinical practice.
In terms of diagnosing a non-bizarre delusion as a delusion, ample support should be provided through fact checking. In case of non-bizarre delusions, Psych Central notes, "All of these situations could be true or possible, but the person suffering from this disorder knows them not to be (e.g., through fact-checking, third-person confirmation, etc.)."
Treatment A challenge in the treatment of delusional disorders is that most patients have limited insight, and do not acknowledge that there is a problem. Most patients are treated as out-patients, although hospitalization may be required in some cases if there is a risk of harm to self or others. Individual psychotherapy is recommended rather than group psychotherapy, as patients are often quite suspicious and sensitive. Antipsychotics are not well tested in delusional disorder, but they do not seem to work very well, and often have no effect on the core delusional belief. Antipsychotics may be more useful in managing agitation that can accompany delusional disorder. Until further evidence is found, it seems reasonable to offer treatments which have efficacy in other psychotic disorders.
There is a certain amount of evidence that alternative treatment-regimes (beyond conventional attempted treatment with antipsychotics) may include clomipramine for people with the somatic subtype of paranoia.Ozen ME, Aydin M, Derici C, Orum MH, Kalenderoglu A. Successful treatment of olfactory reference syndrome with clomipramine. Psiquiatría Biológica. 2018 Jan 1;25(1):29-31. There is a dearth of well-published studies investigating the effectiveness of trimipramine; another derivative of tricyclic-antidepressant imipramine and one which has modest anti-psychotic properties weakly analogous to those of clozapine; in delusional disorder per-se. However, trimipramine was compared to a combination of amitriptyline and haloperidol in a double-blinded trial involving patients with severe, psychotic depression (specifically with customary delusional features) and appeared favourable in its treatment.