The 15 types of hallucinations (and their possible causes)

One of the phenomena most associated with "madness" is hallucinations., that is, perceptions that do not correspond to reality and in which there is no present stimulus that triggers them (unlike illusions).

Hallucinations can appear as a symptom of some mental disorder, for example the schizophrenia, or by the consumption of psychoactive substances such as mushrooms or LSD. The most popular hallucinations are visual and auditory; however, there are others that we will explain to you in this article.

• Related article: "Hallucinations: definition, causes, and symptoms"

What are hallucinations

Basically hallucinations are perceptual experiences non-existent for the rest of the world; they only seem real to the person who lives them. This phenomenon is much more common than most people think, it can occur in any perceptual modality and they usually have characteristics similar to normal perception.

The exact nature of the different types of hallucinations is not entirely clear. However, it is known that people often experience hallucinations because

some chemicals found in drugs influence synapses (the spaces through which neurons communicate with each other) and cause the activation of some brain regions, for example, the parietal lobe in the case of hallucinations of touch.

Other times what triggers hallucinations are dysfunctional neurons that activate certain parts of the brain and they have an effect on normal function. This last phenomenon occurs, for example, due to an excess of dopamine in the case of schizophrenia.

Now, experts assure that lack of sleep can also cause the occurrence of this phenomenonIt has been proven that after 24 hours without sleep a person is more susceptible to experiencing hallucinations. Similarly, spending too much time in sensory deprivation situations can generate visions of elements that are not really there.

• Related article: "Hallucinations when covering the eyes for several hours"

Causes

As you can see, hallucinations can occur for different reasons, not only due to serious mental disorders such as schizophrenia. Some of the most common causative factors are:

• Consumption of medicines and drugs: Consumption of some psychoactive substances such as marijuana, the LSD and even the alcohol are causative factors of this type of experiences.
• Mental illnesses and disorders: Schizophrenia is the psychopathology most associated with this phenomenon; however, other disorders and diseases such as Alzheimer's and dementia, Bipolar disorder, Wernicke-Korsakoff syndrome, temporal lobe epilepsy (TLE), brain tumors, and even Parkinson's also cause hallucinations.
• Brain injuries: Brain injuries can also cause hallucinations, mainly those that occur in the frontal lobe (negative hallucinations, double phenomenon or olfactory, taste and visual hallucinations) or the hippocampus (seeing smaller objects and image changes bodily).

Types of hallucinations

The types of hallucinations can be classified in two ways: according to the sensory modality and according to the mode of appearance.

According to the sensory modality

Depending on the sensory modality, hallucinations can be:

1. Visual hallucinations

One of the best known. They occur when the person sees things that are not really there; for example, by seeing an individual who does not exist. In cases like schizophrenia the sick person may even have a relationship with the imaginary entity. Visual hallucinations can also be flashes of light or autoscopy, that is, seeing oneself from the outside.

2. Auditory

They are also the best known. There is a belief that these hallucinations are voices emitted by a third person and that they have a meaning, for example, to hurt someone, but they can also be single words or sounds. It is more often experienced by people with schizophrenia.

3. Gustatory

These hallucinations are less frequent than the previous ones. They usually appear in some disorders, for example, depression. The person perceives flavors of elements that are not really there.

4. Olfactory

They are also rare, and include those odorous-type hallucinations. They are usually presented by the consumption of drugs and they are generally unpleasant odors. Sometimes they also appear in the moments in which it is expressed along with certain types of migraine, as well as taste and auditory.

5. Somatic

These hallucinations include the sensations of the body of the individual who suffers them, which they feel as real. Some people have reported feeling that they had metal organs, claimed to feel they had no organs or that they did not perceive parts of the body.

6. Touch

They are also known as haptic hallucinations. and include those that have to do with the sense of touch. It is possible to differentiate between thermal (sensations of cold or heat) or hydric (for example, they perceive that they have water in their lungs)

7. Paresthesia

They belong to the previous group but are frequent in some disorders such as Wernicke-Korsakov. The person experiences a tingling sensation, as if he had ants crawling across his skin. They are also frequent with the consumption of other drugs such as cocaine.

8. Kinesic

Kinesic or kinesthetic hallucinations are those related to the movement of one's own body. They are common in patients with Parkinson's and those individuals who use psychoactive substances.

According to the mode of appearance

Depending on the mode of appearance, hallucinations can be:

9. Functional hallucinations

Are presented when one stimulus triggers another in the same sensory modality. For example, when someone hears the noise of real traffic and perceives the sound of the newscast as a hallucination.

10. Reflexes

It is similar to the previous one because the person has a hallucination in the presence of another stimulus. However, this stimulus does not belong to the same sensory modality.

11. Negative

Person perceives that something that actually exists is not present. That is, something does not appear or see something that is not really there at that time or place, but something that is there disappears.

12. Negative autoscopies

It is the complete opposite of autoscopy. If in the autoscopy the person is seen from the outside as if it were a mirror, in the negative autoscopy the person, when you go to look in the mirror, you don't see.

13. Extracampinas

Are those hallucinations that are out of our visual field. For example, when perceiving someone in front as if they were behind, or when hearing a voice that is in another city.

14. Pseudo-hallucinations

Pseudohallucinations are those in which the person you are aware that the hallucinations you experience are not true. For example, when an individual perceives the voice of a deceased relative but knows that it cannot be true because he has been dead for years.

15. Hypnagogic

It is a type of hallucination that also occurs in people without any type of neurological alteration in the transition between wakefulness and sleep. They can be auditory, visual, or tactile.