Delusional Orders


Editor’s Note: Delusional disorder is an illness characterized by the presence of nonbizarre delusions in the absence of other mood or psychotic symptoms. Nonbizarre refers to the fact that this type of delusion is about situations that could occur in real life, such as being followed, being loved, having an infection, and being deceived by one’s spouse. Its causes could be either genetic or biological and Dysfunctional Cognitive Processing. The treatment and prognosis have been exhaustively discussed by the author.


A delusion is a firm, unshakable, false belief that is out of keeping with the person’s social, educational, and cultural background. It is a belief that is fixed and firmly held despite clear contradictory evidence. The word ‘delusion’ comes from the Latin verb ludere, which means “to play”. In essence it means that tricks are played on the mind of an individual. According to the Diagnostic and Statistical Manual, 4th Ed. (DSM-IV), delusional disorder involves a persistent belief in a situation that is imagined but not impossible.

Examples include but are not limited to: a belief that one has an unusual disease, a belief that one has a special relationship with a celebrity, a belief that one is being persecuted etc. The disorder frequently persists lifelong. Delusional disorders, sometimes referred to as paranoia are typically classified as psychotic disorders, however, some researchers further contend that delusional disorder is actually a variation of depression and might respond better to antidepressants or therapy more similar to that utilized for depression.

Patients with this uncommon disorder give voice to or even take actions on the basis of beliefs that are considered completely false and absurd by those around them. Generally, in delusional disorder, these mistaken beliefs would be logically constructed and internally consistent. The individual experiences a heightened sense of self-reference. Events which, to others, are nonsignificant are of enormous significance to him or her.

The person’s other mental functions would be normal, his personality is generally intact, and he is able to work and interact reasonably with others. He/ She may not exhibit odd or bizarre behavior apart from these delusions. According to German psychiatrist, Emil Kraepelin, patients with Delusional Disorder, remain coherent, sensible and reasonable. Their behavior does not show gross disorganization and performance deficiencies and general behavioral deterioration is rarely observed in this disorder even when it is proven chronic.


There six subtypes of delusional disorders, as generally identified.[i]They are:

1. Grandiosetype

This type is delusion of inflated worth, power, knowledge, and identity. The patient believes himself/herself to be a famous person, claiming the actual person is an impostor or an impersonator. In the case of a person named Ah Seng, he was certain that he had special religious powers to cause national disasters and the suicide of a prominent politician. He was deluded that his special powers had evolved from his vegetarian diet and his daily prayers.

2. Somatic type

A person with this type of delusional disorder believes that he or she has a physical defect or medical problem. Often the central theme in somatic delusional disorder is that of the conviction that the individual emits a foul odour from the mouth, skin, or genitalia; or those parts of the body are ugly; or that there are parasites on the body. Sometimes tactile or olfactory hallucinations may be prominent.

For instance : For 5 years a 35-year-old man was convinced that the blood in his left brain was flowing backward, thus causing a “block”, and making his head “uncomfortable” and painful. He adhered to his belief tenaciously despite repeated reassurances by various neurologists. Not surprisingly, he was non-compliant with medications and, eventually jumped to his death when the symptom became intolerable.

3. Erotomanictype

A person with this type of delusional disorder believes that another person, often someone important or famous, is in love with him or her. The person might attempt to contact the object of the delusion or stalk them. This type of delusion is also known as De Clerambault syndrome.

4. Jealous type

The central theme revolves round the delusion of infidelity of the spouse or partner. The diagnosis is made when jealousy is based on inadequate/unsound evidence and reasoning Little bits of “evidence” are used to reinforce the belief that the spouse is carrying on an affair. The individual would painstakingly check the spouse’s intimate belongings of evidence of the “affair” or monitor the spouse’s movements for incriminating evidence of a third party. In its most severe cases, the individual may be so jealous that he resorts to assaults on, or homicide of, the spouse. This is the most dangerous, and is also one of the commonest forms of delusional disorders. Evidence available so far indicates that it is commoner in males than females. It is sometimes known as morbid jealousy or pathological jealousy.

For instance : A 62-year-old elderly and unattractive man was remanded for locking in and seriously attacking his 45-year-old attractive wife at home. Both his teenage children readily testified to his unfounded jealous rantings and checks on his wife for years. It transpired that his first marriage had ended in divorce when his first wife could not tolerate his delusions of infidelity, although he did not assault her then.

5. Persecutory type

This is the commonest type of delusional disorder, the affected individual believes that he is being checked, spied on, harassed, obstructed, conspired against, poisoned, or followed. As a result, he may resort to violence in retaliation against the persecution, or engage in repeated appeals to the courts and other government agencies to “right” the injustice.

For instance: In the case of a person named Ah Seng, his persecutory delusions centred on the harassment of the poor people by the government, and not just on him personally Most government actions were interpreted as part of the systematized plot to make the poor people suffer, and to discredit the opposition so that the government could stay in power. Ah Seng thus resorted to distribution of seditious materials to “right” the injustice done to the people.

 6. Mixed type

In this type of delusion disorder, characteristics of more than one of the above types are observable, but with no one theme predominating.

Apart from the above six, there are unspecified types of delusional disorders, which are delusions that cannot be clearly determined or doesn’t characterize in any of the categories in the specific types.

There is a rare delusional disorder, known as Induced delusional disorder (folie a’ deux) where two people, usually in a very close relationship and are isolated from others by culture, language or physical proximity, share the same delusional system. The theme of the delusional system is often persecutory or grandiose. The delusions are first manifested in the dominant personality, who in turn influences the weaker personality. The former is the only psychotic one, whilst the latter would recover promptly once separation is effected. The delusional system may be part of Schizophrenia, or it may be a primary delusional disorder in itself.


Clear identification of delusional disorder has traditionally been challenging, therefore, scientists have conducted far less research relating to the disorder than studies for schizophrenia or mood disorders. Still, some theories of causation have developed, which fall into several categories.

Genetic or Biological 

Close relatives of persons with delusional disorder have increased rates of delusional disorder and paranoid personality traits. Increased incidence of these psychiatric disorders in individuals closely genetically related to persons with delusional disorder suggests that there is a genetic component to the disorder. Furthermore, a number of studies comparing activity of different regions of the brain in delusional and non-delusional research participants yielded data about differences in the functioning of the brains between members of the two groups. These differences in brain activity suggest that persons neurologically with delusions tend to react as if threatening conditions are consistently present. Non-delusional persons only show such patterns under certain kinds of conditions where the interpretation of being threatened is more accurate. With both brain activity evidence and family heritability evidence, a strong chance exists that there is a biological aspect to delusional disorder.

Dysfunctional Cognitive Processing

Delusions may arise from distorted ways people have of explaining life to themselves. The most prominent cognitive problems involve the manner in which delusion sufferers develop conclusions both about other people, and about causation of unusual perceptions or negative events. Studies examining how people with delusions develop theories about reality show that the subjects have ideas which they tend to reach an inference based on less information than most people use.

This “jumping to conclusions” bias can lead to delusional interpretations of ordinary events. For example, developing flu-like symptoms coinciding with the week new neighbors move in might lead to the conclusion, “the new neighbors are poisoning me.” The conclusion is drawn without considering alternative explanations—catching an illness from a relative with the flu, that a virus seems to be going around at work, or that the tuna salad from lunch at the deli may have been spoiled.

Additional research shows that persons prone to delusions “read” people differently than non-delusional individuals do. Whether they do so more accurately or particularly poorly is a matter of controversy. Delusional persons develop interpretations about how others view them that are distorted. They tend to view life as a continuing series of threatening events. When these two aspects of thought co-occur, a tendency to develop delusions about others wishing to do them harm is likely.

Motivated or Defensive Delusions

Some predisposed persons might suffer the onset of an ongoing delusional disorder when coping with life and maintaining high self-esteem becomes a significant challenge. In order to preserve a positive view of oneself, a person views others as the cause of personal difficulties that may occur. This can then become an ingrained pattern of thought.


The criteria that define delusional disorder as furnished in the Diagnostic and Statistical Manual of Mental Disorders[ii], published by the American Psychiatric Association are :

  • non-bizarre delusions which have been present for at least one month
  • absence of obviously odd or bizarre behaviour
  • absence of hallucinations, or hallucinations that only occur infrequently in comparison to other psychotic disorders
  • no memory loss, medical illness or drug or alcohol-related effects are associated with the development of delusions

It is often found that people suffering from the disorder are usually found with the following circumstances:

  • Hearing deficiency, resulting in social isolation
  • Prisoners in solitary confinement; refugees; immigrants, all of whom experience solitary isolation
  • Low socioeconomic status
  • Paranoid, Schizoid, or Avoidant Personality Disorder – which may be associated with Delusional Disorder.

The patient expresses an idea or belief with unusual persistence or force. That idea appears to exert an undue influence on the patient’s life, and the way of life is often altered to an inexplicable extent. The individual tends to be humourless and oversensitive, especially about the belief. There is a quality of centrality which means that no matter how unlikely it is that these strange things are happening to him, the patient accepts them relatively unquestioningly. An attempt to contradict the belief is likely to arouse an inappropriately strong emotional reaction, often with irritability and hostility.

The belief is, mostly, at the least, unlikely, and out of keeping with the patient’s social, cultural and religious background. The patient is emotionally over-invested in the idea and it overwhelms other elements of their psyche. The delusion, if acted out, often leads to behaviours which are abnormal and/or out of character, although perhaps understandable in the light of the delusional beliefs. Individuals who know the patient observe that the belief and behaviour are uncharacteristic and alien.


Diagnosis is made on the basis of the systematized and encapsulated delusions, in the absence of other psychotic symptoms that would imply the presence of Schizophrenia, Schizoaffective Disorder, Mania or Depression. General medical conditions, such as thyroid disorders, systemic lupus erythematosus, dementia, etc., should be excluded as the cause of the delusions. In addition, conditions like substance abuse (cocaine, amphetamine, etc.) should also be excluded as the cause of the delusions.

Delusions also occur as symptoms of many other mental disorders, especially the other psychotic disorders. They are common symptoms in schizophrenia. It occurs in more that 90%of patients at some time in their illness. However, not all people who have delusions suffer from schizophrenia.  Thus to be diagnosed with delusional disorder a person should not be suffering from schizophrenia. It is also to be noted that the patient’s personality and psychosocial functioning are not significantly affected by the disorder. Based on the DSM-IV, the symptoms should be present for at least a month, whilst based on the ICD-10, the symptoms should be present for at least 3 months.

Client interviews focus on obtaining information about the sufferer’s life situation and past history aid in identification of delusional disorder. With the client’s permission, the clinician obtains details from earlier medical records, and engages in thorough discussion with the client’s immediate family. These have proven to be helpful measures in determining whether delusions are present. The clinician may use a semi-structured interview called a mental status examination to assess the patient’s concentration, memory, understanding the individual’s situation and logical thinking. The mental status examination is intended to reveal peculiar thought processes in the patient.

The Peters Delusion Inventory (PDI) is a psychological test that focuses on identifying and understanding delusional thinking; but its use is more common in research than in clinical practice.

Even using the DSM-IV-TR criteria listed above, classification of delusional disorder is relatively subjective. The criteria “non-bizarre” and “resistant to change” and “not culturally accepted” are all subject to very individual interpretations. They create variability in how professionals diagnose the illness. The utility of diagnosing the syndrome rather than focusing on successful treatment of delusion in any form of illness is debated in the medical community.


It is important to decide if the patient requires outpatient or in-patient treatment at the outset. This would be determined by the presence of violence or social difficulties. Involuntary admission may sometimes be necessary to protect the patient or others, especially in pathological jealousy.

In treatment the psychiatrist should try to establish rapport and not condemn nor collude with the delusions. Assurance, respect, and psychological support would help in gaining the patient’s confidence in the therapeutic relationship. Group therapy and interpretative therapy are unsuitable as the patient tends to be suspicious and hypersensitive, and would misinterpret the process.

Delusional disorder treatment often involves atypical (also called novel or newer-generation ) antipsychotic medications, which can be effective in some patients. Risperidone (Risperdal), quetiapine(Seroquel), and olanzapine(Zyprexa) are all examples of atypical or novel antipsychotic medications. If agitation occurs, a number of different antipsychotics can be used to conclude the outbreak of acute agitation. Agitation, a state of frantic activity experienced concurrently with anger or exaggerated fearfulness, increases the risk that the client will endanger self or others.

To decrease anxiety and slow behaviour in emergency situations where agitation is a factor, an injection of haloperidol (Haldol) is often given usually in combination with other medications (often lorazepam , also known as Ativan). Agitation in delusional disorder is a typical response to severe or harsh confrontation when dealing with the existence of the delusions. It can also be a result of blocking the individual from performing inappropriate actions the client views as urgent in light of the delusional reality.

A novel antipsychotic is generally given orally on a daily basis for ongoing treatment meant for long-term effect on the symptoms. Response to antipsychotics in delusional disorder seems to follow the “rule of thirds,” in which about one-third of patients respond somewhat positively, one-third show little change, and one-third worsen or are unable to comply.

The chief problem is that the majority of persons with Delusional Disorder have no insight into their problems and almost certainly would reject medications. Attempts should be made to persuade the patient to accept depot injections such as Flupenthixol Decanoate if compliance with oral medications is in doubt.

Cognitive therapy has shown promise as an emerging treatment for delusions. The cognitive therapist tries to capitalize on any doubt the individual has about the delusions; then attempts to develop a joint effort with the sufferer to generate alternative explanations, assisting the client in checking the evidence. This examination proceeds in favour of the various explanations.

Much of the work is done by use of empathy, asking hypothetical questions in a form of therapeutic Socratic dialogue—a process that follows a basic question and answer format, figuring out what is known and unknown before reaching a logical conclusion. Combining pharmacotherapy with cognitive therapy integrates both treating the possible underlying biological problems and decreasing the symptoms with psychotherapy.


The prognosis for clients with delusional disorder is largely related to the level of conviction regarding the delusions and the openness the person has for allowing information that contradicts the delusion. Some run a chronic course as the delusions are firmly held and treatment is often rejected. Others may remit completely within a few months, while yet others may remit and relapse over the years. Notwithstanding the refusal of medication, a satisfactory outcome may be temporarily achieved if the psychiatrist is able to dissuade the patient from acting on his abnormal beliefs.


 [i] The Diagnostic and Statistical Manual of Mental Disorders (DSM) also gives this classification

[ii] Fourth Edition Text Revision ( DSM-IV-TR )

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