By hallucination we mean the perception of a sensory phenomenon when in reality it is not real. To simplify the concept, it can be said that it is an imagination of something that does not actually exist, but which nevertheless stimulates the sensitive brain centers, thus giving the perception that that phenomenon has really happened.
A clear distinction must then be made between hallucination and illusion , in fact the latter is based on a phenomenon that exists in reality but that the mind alters and distorts with respect to its true entity.
In some cases the subject is aware that what he perceives is not concrete and is therefore able to distinguish what is real from what is imaginary, but in other cases, especially in subjects suffering from psychosis or neurodegenerative diseases, perception hallucinations and unconscious, therefore they do not distinguish reality from what is imaginary.
Hallucinations can be of a simple type , when simple sounds, flashes of light, geometric shapes, spheres or circles are perceived, or of a complex type, when the hallucinations appear as very elaborate constructions in which the subject perceives people, animals, objects, situations , landscapes and imaginary scenes.
We can therefore distinguish thehallucinations based on the 5 sense organs, to which is added proprioception, i.e. the perception of what happens inside the organism, and therefore are divided into:
- Olfactory hallucinations (or cacosmia or phantosmia): in which there is the persistent perception of pungent and annoying odors that do not exist, and can often be associated with the presence of a brain tumor whose mass compresses the areas of the cortex responsible for olfactory sensitivity;
- Auditory hallucinations: this is the most common category of hallucination and is based on the perception of noises or sounds that do not exist. In subjects suffering from schizophrenia these sounds are transformed into real voices that can condition the subject’s behavior or induce him to perform actions;
- Visual hallucinations: as seen before, they can be of a simple type, with the perception of flashes of light, spots, geometric shapes or spheres, or of a complex type, when they are rather constructed and elaborate. Sometimes a feeling of deja-vu can be generated, in which one has the impression of being in a context already experienced previously;
- Tactile hallucinations: generally they are those that instill greater anxiety and fear, with the sensation that something is moving under the skin or that it crawls or walks on you;
- Taste hallucinations: one has the impression of having a persistent taste in the mouth which is defined as metallic, bitter or earthy, even when the taste buds are not stimulated by any substance;
- Proprioceptive and visceroceptive hallucinations : in these cases there is the sensation of something happening inside the body, even when in reality there is no concrete reason. You may feel chills, paralysis or even feel that the floor is moving under your feet.
Hallucinations
are a common symptom of many conditions, which however are not always pathological, in fact in most cases they occur following the intake of substances capable of altering perception (drugs such as LSD, cocaine, opium, peyote, alcohol, but also some drugs) or periods of severe fatigue in which sleep disturbances occur.
In other cases, however, hallucinations are a symptom common to different pathologies of psychiatric and neurological interest.
We are going to deepen some of the conditions mentioned below. Let’s turn the page to learn more.
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