According to the generalized interpretation of various doctors and specialists, illusions are an erroneous, distorted or altered perception of real objects or any phenomena; according to J. Eskirol, it is a "perversion of perception", F. Pinel called this state "a delusion of the imagination", and V.P. Serbian called this phenomenon "imaginary".
Illusions can arise not only in mentally ill people, but also in a perfectly healthy person. In healthy people, similar symptoms may appear due to inattention, and manifestations of physical or physiological sensations of this kind are also known.
Doctors believe that these phenomena are based on the ordinary laws of physics. Thus, the refraction of objects at the border of different transparent media is perceived in a completely different way, distorted (for example, a spoon in a transparent glass with water is visually "refracted"). A striking example of such a distortion is the illusion widely known to all - the appearance of mirages in the deserts.
The physiological background of illusions is associated with the specifics of the functions of the analyzers. If you look at a moving train for a long time, you get the feeling that it is standing still, and the one looking, on the contrary, seems to be moving in the opposite direction. If the rotating swing stops abruptly and suddenly, then the people sitting in it for a few more moments retain the feeling of the rotation of their environment.
The reasons for the distortion and refraction of the perception of the surrounding world are far from always based on painful sensations of a person, this can be caused by special properties of the environment, physiological characteristics of the human body, excessive impressionability and self-doubt, some of them, in certain cases, are mandatory for everyone (fear , surprise).
All types of illusions differ in sensations and perceptions of the senses in the area of which they appear. According to the conditions of their occurrence, all illusions are divided into phenomena of physical, physiological and mental manifestation.
Illusions of a mental or pathological type are due to reasons of a psychological nature, and consist in various violations of human activity in the field of attention, sensory tone, memory, clear perception of the associative array. The mental illusions of the mentally ill lie in the area of a special pathological phenomenon. This type of illusion is divided into affective and verbal phenomena, as well as pareidolia.
The emergence of affective illusions is possible in situations of affect or an emotional state unusual for a person - with strong fear, excessive desire, as a rule, unattainable, tense expectation, depression and anxiety. Affective illusions arise especially often during the period of painful changes in the emotional state.
It is possible for a similar phenomenon to occur in completely certain environmental conditions, for example, with insufficient illumination, at dusk, at night when lightning flashes (at this moment, the light illumination is distorted and refracted). A moving curtain can be perceived as a lurking robber, a belt on an armchair - like a snake ready to jump, etc.
Affective illusions also arise in cases where, in addition to affective tension, weakness (indistinctness) of the irritable sign (distance of the object, quiet rustling sounds, indistinct indistinct speech) and signs of obvious asthenia appear.
Any perfectly healthy mentally person can experience the phenomenon of an affective illusion if he is in an unfamiliar environment, an unfamiliar place, in an unusual emotional state (a classic example is a visit to a cemetery at night).
"Materialized" into affective illusions in a healthy person and the constant expectation of something unpleasant for him (for example, if a person is very afraid of dogs, then in an unfamiliar environment with poor lighting every extraneous movement will seem to him rushing at him a dog).
The emergence of verbal, or auditory illusions can also occur on the basis of some kind of emotional state and be expressed in an erroneous distorted perception of the meaning or sound of the conversation of people around, while neutral ordinary speech (its meaning) the sick person perceives (or interprets subconsciously) as a threat to his life, insults, abuse or accusations.
Affective illusions in sick people arise in various painful conditions, at different stages of the development of diseases, they appear in delirium, anxiety-depressive syndrome, paraphrenic syndrome, paranoid syndrome.
The initial stages, for example, the development of delirium, acute stages of paraphrenic and paranoid syndromes are characterized by the emergence of affective illusions, expressed in feelings of threat, with deceptive sensations - sounds of a metal type are perceived as a gun sound, water pouring from a tap - as an incipient flood, etc.
Psychopathologically, affective or verbal illusions are highly heterogeneous. Some of them relate to depression, some are a reflection of the influence of the state of delusion, some illusions are expressed by distinct persistent delusional (erroneous) beliefs. As a rule (in most cases), affective illusions are associated with the emergence of a leading affect and are based on psychopathological symptoms.
The emergence of affective illusions is characteristic of the patient, not only in a state of simple depression, but also with obvious tendencies towards a depressive phenomenon of delusion. A sick person who is in a state of activated depression of a delusional type is constantly in anticipation of punishment, execution, retribution for sins, condemnation of others.
At the same time, in a healthy person, it is imperative to distinguish erroneous judgments or wrong conclusions made under the influence of some physical phenomenon from affective illusions.
So, for example, you can easily take a shiny object on the ground for a coin, or a shard of glass brightly illuminated by the sun for gold, this phenomenon is not considered an illusion, that is, not a deception (false perception) of a sensual definition of something, but an erroneous, misinterpreted judgment.
Psychologists and psychiatrists are well aware that the emergence of individual manifestations of affective illusions (isolated manifestation) is not at all considered a mental illness or its symptom, but most often, is evidence of affective tension (arising from overwork, sudden fright, fear).
A symptom of a disease can be considered exclusively a combination of manifestations of affective illusions in combination with other painful manifestations and mental disorders.
The main difference between physiological illusions and pathological manifestations of affective illusions is considered by doctors to be the possibility of correcting the condition, as well as the patient's self-critical attitude to his own state (awareness of the illusory nature of what is happening).
In these cases, with any change in the conditions under which an erroneous perception was created (bright light or a change in the state of the central nervous system, another situation, etc.), as well as the introduction of previously perceived distorted images into objective reality lead to the "exposure" of affective illusions. And a person reveals his own mistake on his own - which serves as a reason for the destruction of the illusion.
In the event of persistent affective illusions of a pathological nature, the critical attitude to what is happening in the patient decreases, the illusions become even more stable, and their intensity can be reduced only during treatment, as the disease state changes positively during remission.