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Delusions: who gets them and why?
Last reviewed: 04.07.2025

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If ideas are a form of mental representation of objective reality, then delusional ideas are defined as subjective concepts and beliefs that do not correspond to the real existing relationships of phenomena. This is a distorted reflection in consciousness of certain aspects of reality and situations that, as a rule, do not go beyond the limits of possibility.
The formation of false ideas indicates certain disturbances in thought processes that have a special diagnostic significance: in almost all cases, delusional ideas appear in schizophrenia and manic episodes of bipolar disorder or affective psychosis.
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Epidemiology
Information on the epidemiology of delusional disorders is limited and not systematic. According to the American Journal of Neuropathology, the prevalence of delusional disorder is estimated at approximately 0.2%, which is significantly lower than the incidence of schizophrenia (1%) and mood disorders (5%).
According to data from British psychiatrists, during the first episode of psychosis, psychotic depression is diagnosed in 19% of cases, schizophrenia in 12%, and persistent delusional disorder in approximately 7% of patients who seek help.
Men are more likely to develop paranoid delusions, while women are more likely to develop delusional ideas of erotic themes. The average age of onset of the disease is 45-55 years, although this condition can also be observed in young people. However, it is still more common among older people, of whom at least 57% are women.
Causes delusions
In modern psychiatry, the causes of delusional ideas – as well as obsessive and overvalued ideas – are associated with a disruption of the cognitive structure of thinking, its direction (content), associativity and logic. That is, the ability to identify and perceive a logical connection between elements of incoming information is partially lost, replaced by the construction of one’s own “chain” of subjectively isolated and falsely understood facts, additionally distorted by inadequate associations.
Experts claim that the key thinking disorder in delusional ideas consists of the deformation of its personal-motivational component, and this leads to false interpretations of the internal state of the individual and self-esteem, as well as interpersonal and social connections - with inadequate conclusions regarding their causes, motives and consequences.
One of the neuropsychological models of the development of schizophrenia and paranoia is considered as a possible mechanism for the emergence of delusional conclusions. This is a model of cognitive bias (or motivated defensive delusion), the meaning of which is that in people with a hypochondriacal psychotype, anomalies in the form of delusional ideas serve as protection from thoughts that threaten their idealized “I” - to maintain self-esteem. Positive events are attributed to oneself (which indicates a decrease in critical thinking), while everything negative in life is correlated only with external influences, and a person always considers circumstances and others to be the cause of his personal difficulties.
By the way, according to the majority of psychiatrists, delusional disorder and delusional ideas in schizophrenia are not identical conditions, since cognitive deficit and emotional-behavioral inadequacy in schizophrenia are more pronounced, and thematically bizarre delusions have a variable (fragmentary) nature.
Risk factors
The main risk factors for the emergence of delusional ideas are considered to be:
- background influences of temperament and personality;
- stress and traumatic situations (divorce, job loss, recent immigration, low socioeconomic status, celibacy among men and widowhood among women);
- alcoholism and drug addiction;
- use of psychostimulants;
- brain damage due to traumatic brain injury;
- syphilis of the brain and other infections affecting brain structures;
- some types of epilepsy;
- neurodegenerative diseases – Parkinson's disease and Alzheimer's disease;
- cerebrovascular pathologies (impaired cerebral blood flow), in particular, cerebral amyloid angiopathy (leading to weakening and rupture of brain vessels), subcortical microbleeds of the brain, ischemic stroke and cerebral infarction.
Pathogenesis
Research is being conducted to clarify the pathogenesis of this mental disorder. In particular, a certain role of genetic predisposition to the emergence of persistent delusional ideas has already been recognized, especially if there are patients with personality disorder or schizophrenia in the family.
According to the latest research by geneticists and scientists in the field of cognitive and experimental psychology, many patients with delusional disorders have been found to have polymorphism of genes of dopamine receptors (D2) on membranes of dopaminergic and postsynaptic neurons. These receptors provide inhibition of signals going to neurons, and with their genetic anomaly, the dopamine neuromodulation system of the brain can malfunction.
In addition, the possibility of accelerated oxidation of this most important endogenous neurotransmitter with the formation of quinones and free radicals, which have a toxic effect on the cells of the cerebral cortex and other structures of the brain, cannot be ruled out.
Although delusional ideas are most often associated with mental disorders, they can arise in neurodegenerative processes associated with a reduction in the number of neurons in the brain. Thus, in elderly and senile patients with dementia, presenile and senile psychosis, a combination of depression and delusional ideas is noted, the appearance of which is due to damage to the right hemisphere of the brain, calcification of the basal ganglia, hypoperfusion of the parietal and temporal lobes, as well as disorders of the limbic system of the brain.
Symptoms delusions
Psychiatrists consider symptoms of delusional ideas as part of the diagnostic criteria for schizophrenia, delusional disorder, or bipolar affective disorder (during the manic stages). Obsessive delusional ideas may be one of the symptoms of paranoid personality disorder.
In the formation of a delusional idea, the following stages are distinguished:
- emotional tension with mood swings, reflecting total changes in the perception of the surrounding reality;
- search for new connections and meaning in unrelated events;
- intensification of experiences associated with a sense of involvement in everything that happens around;
- the formation of a new “psychological set” (retrospective falsification or delusional memory) after the final strengthening of an unshakable conviction in the truth of one’s false ideas;
- the emergence of a psychologically uncomfortable condition, close to autistic, that is, difficulties in communication, social communication and social interaction are observed.
Although at first people who develop delusional ideas usually do not show noticeable disturbances in everyday life, and their behavior does not give objective reason to consider it bizarre.
The first signs are manifested by unmotivated mood swings. The affect is consistent with the delusional content (increased anxiety, a feeling of hopelessness or helplessness, suspiciousness and mistrust, suspicion or resentment). Regardless of the type of delusional ideas, dysphoria may be present - a gloomy mood and angry irritability.
Due to the peculiarities of the emotional state, speech, visual contact and psychomotor skills may be affected. However, memory and level of consciousness are not impaired.
The somatic type of delusional ideas may be accompanied by tactile or olfactory hallucinations; auditory or visual hallucinations are characteristic of more severe psychotic disorders, such as schizophrenia.
In chronic alcoholism with delusional ideas of persecution, verbal alcoholic hallucinosis is observed.
It is important to keep in mind the peculiarity of such disorders: people suffering from delusional ideas demonstrate absolute confidence in their correctness and do not perceive even obvious evidence to the contrary.
Contents of delusional ideas
Types of delusional thinking in psychiatric patients are usually classified by their subject matter (content). For example, the content of delusional ideas in schizotypal disorder and paranoid syndrome concerns external control (the person is convinced that an external force controls his thoughts or actions), his own grandeur, or persecution.
In domestic clinical psychiatry, as well as in the American Psychiatric Association's diagnostic manual for mental disorders (DSM-5), the following main types (kinds) of delusional ideas are distinguished.
Delusional ideas of persecution are considered the most common. With them, patients are extremely suspicious and believe that someone is watching them, wanting to cause harm (deceive, attack, poison, etc.). Moreover, such delusional ideas in schizophrenia lead to a decrease or complete cessation of social functioning of the individual, and in cases of delusional disorder, delusions of persecution are characterized by systematization and consistency, and such people often write complaints to various authorities, trying to protect themselves "from intruders."
Delusional ideas of jealousy (morbid or psychotic jealousy, delusional jealousy ) haunt a spouse or sexual partner who is convinced of infidelity. A person obsessed with delusional jealousy controls the partner in every way and looks for “proof” of infidelity everywhere. This disorder can be diagnosed in connection with schizophrenia or bipolar disorder; it is often associated with alcoholism and sexual dysfunction; it can provoke violence (including suicide and murder).
Erotic or love delusions are reduced to the patient's false belief that another person, usually of higher status, is in love with him. Patients may try to contact the object of their desires, and the denial of this feeling on his part is often falsely interpreted as confirmation of love.
Delusional ideas of grandeur are expressed in the belief that the individual has exceptional abilities, wealth, or fame. Experts classify this type as a symptom of delusions of grandeur, narcissism, as well as schizophrenia or manic episodes of bipolar disorder.
Referential delusions or delusional ideas of reference consist of projecting everything that happens around a person personally onto the person: patients believe that everything that happens is somehow connected to them and has a special meaning (usually negative).
This type of irrational belief causes a person to withdraw into themselves and refuse to leave the house.
Somatic delusions involve preoccupation with the body and typically consist of erroneous beliefs about physical defects, incurable diseases, or infestations with insects or parasites. Sensory experiences, such as the sensation of parasites crawling inside, are considered components of systematized delusional disorder. Such patients are usually first seen by dermatologists, plastic surgeons, urologists, and other physicians to whom they refer.
In addition, the following are distinguished:
- Delusional ideas of damage concern the conviction that a person's personal belongings, money, documents, food, kitchen utensils, etc. are constantly being stolen. Anyone can suspect theft, but first and foremost, relatives and neighbors.
- delusional ideas of control or influence - the belief that feelings, thoughts, or actions are imposed on a person by some external force that controls them;
- delusional ideas of self-abasement - a false belief that a person has no abilities and is not worthy of even the most ordinary household amenities; manifests itself in the form of a deliberate refusal of all types of comfort, normal food and clothing. A combination of depression and delusional ideas of self-abasement is typical;
- delusional idea of guilt and self-flagellation makes a person think that he is bad (unworthy), claiming to have committed an unforgivable sin. Also often encountered in depressions and can push to suicide.
In the mixed type of false ideas, the patient simultaneously exhibits more than one delusional idea without any one of them clearly dominating.
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Complications and consequences
The indicated disorders of thinking have quite serious consequences and complications, which manifest themselves in the form of:
- - deep emotional depression;
- aggressiveness and attempts at violence against others (especially in cases of delusional jealousy);
- alienation;
- spreading delusional ideas to a larger number of people or situations;
- persistent impairment of logical thinking (alogy);
- partial disorganization or catatonic behavior.
Diagnostics delusions
How is delusional ideas diagnosed and delusional disorder identified? First of all, based on communication with the patient (using special methods) and his full anamnesis, the doctor must be sure of the presence of the corresponding symptoms, since the patients themselves are unable to recognize the presence of the problem.
When making a diagnosis, certain criteria for identifying the pathology are used (including the diagnostic criteria of DSM-5). The duration of the disorder, its frequency and forms of manifestation are determined; the degree of plausibility of delusions is assessed; the presence or absence of confusion, severe mood disorders, agitation, distortion of perception (hallucinations), physical symptoms are identified; the adequacy/inadequacy of behavior is determined.
There are no specific laboratory tests to diagnose this condition, but blood tests and imaging tests may be required to rule out physical disease as the cause of the symptoms. These include computed tomography or magnetic resonance imaging of the brain, which can visualize damage to its structures that causes CNS diseases.
Differential diagnosis
Differential diagnostics is especially important. According to psychiatrists, delusional ideas are easiest to identify in schizophrenia (they are always bizarre and absolutely implausible), but it can be difficult to distinguish delusional disorder from obsessive-compulsive or paranoid personality disorder. And it is necessary to differentiate delusional idea from obsessive and overvalued (inflated or dominant).
The distinguishing characteristics of obsessive states from delusional ideas are the ability of patients to think rationally about their condition: obsessive ideas cause them anxiety and confidence in their painful origin. Therefore, patients with obsessions, in order not to discredit themselves, are not inclined to talk about their experiences to random people, but are quite frank with the doctor to whom they turn for help. However, clinical observations show that in some cases, obsessive-compulsive disorder or obsessive-compulsive neurosis and delusional idea, that is, their simultaneous presence in patients, is possible - when patients try to find a justification for them.
Overvalued ideas are extremely rarely strange and concern ordinary and plausible aspects of reality and life circumstances of a person. Such ideas are ego-syntonic (perceived positively) and are considered a borderline state. And the pathology lies in the exaggeration of their importance and significance, as well as the person's concentration only on them. Some specialists distinguish overvalued delusional ideas due to their dominance in consciousness, although overvalued ideas, unlike delusional ones, are supported by patients with less intensity.
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Treatment delusions
Treating delusional ideas is difficult for a variety of reasons, including patients' denial that they have psychological problems.
Today, the correction of delusional ideas consists of symptomatic treatment with the use of drugs and cognitive-behavioral and psychotherapy.
Medicines from the pharmacological group of antipsychotics (neuroleptics) can be prescribed - Pimozide, Olanzapine (other trade names - Olanex, Normiton, Parnasan), Risperidone (Respiron, Leptinorm, Neipilept), Clozapine (Klozasten, Azaleptin, Azaleprol), as well as antidepressants, for example, Clomipramine (Klominal, Klofranil, Anafranil). The dosage of these drugs and the duration of administration are determined by the doctor on an individual basis - based on the patient's condition, the presence of somatic diseases and the intensity of symptoms.
It is necessary to take into account contraindications of these drugs and their side effects. Thus, Pimozide is contraindicated in Parkinson's disease, diseases of the mammary glands, angina, liver and kidney failure, pregnancy. Olanzapine and Risperidone are not prescribed for epilepsy, psychotic depression, prostate diseases, liver problems. Clozapine cannot be taken if patients have epilepsy, glaucoma, heart and kidney failure, alcohol dependence.
Pimozide may cause side effects such as cardiac arrhythmia, tremors and seizures, muscle spasticity, gynecomastia (in men) and breast engorgement (in women). Possible side effects of Olanzapine include drowsiness, eyelid enlargement, decreased blood pressure and CNS depression. And when using Risperidone, in addition to stomach pain, increased heart rate, decreased blood pressure, dizziness and disturbances of consciousness may occur, worsening the well-being of patients with impaired thinking.
Forecast
This disorder is a chronic condition and usually does not result in significant impairment or personality change: most patients do not lose their ability to work.
However, symptoms can become more severe, and the prognosis for each person suffering from this painful condition varies depending on the type of delusion and life circumstances, including the availability of support and willingness to adhere to treatment. Most often, delusions persist throughout life, with periods of remission.
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