Experts call kakosmia very rare olfactory illusions, which consist in the fact that perception plays "interesting" games with a person - changes smells, and, as a rule, in a negative direction. That is, familiar and pleasant smells, illusory, take on a sharply disgusting character (in a broader sense, the word kakosmia means any unpleasant smell).
In medicine and psychology, the term "kakosmia" (also, dysosmia, parosmia) denotes a kind of affective illusion - distortion, imaginary smells, a kind of violation of the sense of smell under the influence of stress, excitement, fears, sudden change of environment, etc.
However, almost all experts note two important factors, firstly, this phenomenon, unfortunately, has not been practically studied (neither its nature, nor correct diagnosis) to this day, and, secondly, it is little distinguishable from olfactory hallucinations (sometimes generally merges with them).
In addition, the occurrence of illusions of smell often arises for natural medical reasons, unrelated to the human psyche, as a consequence of common diseases - caries, chronic tonsillitis, sinusitis in chronic or acute form, various types of pathological conditions of the gastrointestinal tract.
At the same time, from the point of view of psychiatrists and psychologists, the causes of olfactory illusions or hallucinations (an unpleasant smell of mold, vinegar, decay, etc.) lie in the field of pathology, and they speak of erroneous irritation of receptors as a result of a pathological process in the cortical olfactory projection area. And, above all, about the violation of the hook of the parahippocampal gyrus, which is responsible for the formation of some behavioral moments associated with the area of emotions and instincts.
Olfactory illusions (or hallucinations) can also occur as a result of a partial epileptic seizure, since the manifestation of olfactory agnosia (in this case, illusions), the emergence of a process of impairing the recognition of a well-known previously smell, are directly related to focal, bilateral processes lying in the hippocampus zone ...
It should not be disregarded that olfactory disorders (olfactory illusions) often occur in the course of various diseases that are not related to lesions of the nervous system, this concerns hypothyroidism, diabetes mellitus, scleroderma, Paget's disease, etc.
General practitioners are well aware of cases of parosmia, the manifestation of unusual imaginary sensations, olfactory illusions during exposure to standard stimuli of smell in inflammatory lesions of the nasopharynx, during the restoration of a reduced (in case of illness) sense of smell.
Doctors call the phenomenon of olfactory illusions the fact that after colds (especially viral) diseases, the possibility of smelling sharply decreases, but before the disease (during the incubation period) the phenomenon of hyperosmia always occurs (sharp increased olfactory sensitivity).
Doctors call the cause of heightened sense of smell at the beginning of the disease as a kind of compensatory affect of consciousness, provoking the search for the means necessary for recovery.
In the event that a person has an impaired sense of smell, then only one sensation arises - taste, and the usual perception registers only 4 main types of taste - sweet and salty, bitter and sour, and all the specific subtleties inherent in the taste of various food products disappear because they are related to smell.
With a severe cold, gustatory and olfactory illusions can involuntarily arise simultaneously - the onion has a sweet taste, and smells like an apple. An amazing fact - after suffering colds (especially viral) diseases, the sense of smell sharply decreases, but on the eve of the disease (during the incubation period), hyperosmia always occurs.
As a rule, odor distortions and olfactory illusions arise completely unexpectedly, suddenly perception changes, and a person begins to feel the smell of burning in the aroma of citrus fruits (a common case) or a smack of sulfur in hot odorous spices. Along with the distortion (illusion) of olfactory perception, gustatory illusions appear.
The phenomenon of illusory perception of odors is also called chemoreceptor anesthesia (dullness) or hypersthesia (exacerbation), they can occur at different times, some - periodically (at the beginning of the menstrual cycle, after suffering a traumatic brain injury, severe nervous shock).
And the periods when a person tries to quit drinking alcohol, using drugs, smoking (or starving) are characterized by sharp perversions, illusions of smell, many people have to learn to re-perceive previously familiar smells.
On the other hand, the fact that many experts believe that smell refers to the concepts of reality, since it contains molecules that affect olfactory analyzers - receptors that are able to cause a "response" of consciousness, speaks of the fact that the phenomenon of olfactory illusions has not been studied. but at the same time at the level of the passage of a biochemical reaction.
This is an interesting enough theory, but, like all theories about the occurrence of olfactory illusions, it is controversial. And, nevertheless, there are many examples proving that the illusions of smells arise in absolutely healthy mentally and without therapeutic deviations.
For example, there are many people who smell salt in food. Although, as you know, salt is an odorless product, however, the consciousness of these people is so "aimed" to feel it, that it is felt.
There are concepts - "the smell of fear", "the smell of hatred", and, despite the fact that doctors tend to interpret them as a special smell of sweat secreted by a person under stress, psychologists call this phenomenon the illusion of smell.
In fact, the olfactory analyzer (receptors) is a set of complex sensory structures responsible for the perception, transportation and analysis of odors entering the nasal passages, while inextricably linked with taste sensations. However, the very nature of smells can provoke the appearance of illusory sensations, that is, the phenomenon of olfactory illusions.
The complex process of erroneous perception of olfactory sensations (olfactory illusions) is associated, to a greater extent, not with the natural smell emanating from the source, but with the current state of human health (we are not talking about mental disorders).
And also, with the individual characteristics of physiology (it is not for nothing that there are "sniffers", people with an extremely developed sense of smell), memory and emotions, associations, including the consequences of trauma, the ability to make inferences, and erudition.
Psychologists very often encounter such a phenomenon when they are approached by people who tell them that a substance (perfume, deodorant, soap) that was well known and pleasant even yesterday smells "wrong", and give an example of their own research.
These people were asked to first smell the "correct" colognes (they agreed that it was), and then, from several identical colognes, the one (marked) that smelled "wrong", in 99 out of 100 cases they chose unmarked.
This is a vivid example of an olfactory illusion provoked by a specific state of a person at that specific moment (a shock, resentment, disappointment, etc.)
Psychologists say that a person perceives smells in two ways - natural, real, and imaginary - areal, since any smell evokes associative images associated with past events in the mind.
Most acutely, this concerns precisely the smells and sounds of music, these two phenomena can change the existing reality for a person, replacing it in consciousness (and, therefore, in perception) with memories from the past, and cause an olfactory illusion.
The sense of smell, like no other, is connected with the human psyche. With the help of some "bright" and memorable smells, you can manipulate the human mind. In addition, with the help of smell, psychologists manage to change a person's mood, intentions and actions.
The phenomenon of perversion, illusion or weakening of the sense of smell may not appear for a long time, and occur gradually, in a perfectly healthy person under certain conditions - in cases of frequent alcohol abuse, at a time of severe stress, with depression, during a severe pregnancy, during menopause, with taking drugs and as a side effect when taking certain medications.
Any olfactory illusion is a deception of the senses, which can, unfortunately, easily go from the form of ordinary distortions to painful olfactory illusions and hallucinatory olfactory images.