The 15 types of hallucinations (and their possible causes)

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

Hallucinations can appear as a symptom of certain mental disorders, for example schizophrenia, or of the use of psychoactive substances such as mushrooms or LSD. The most popular hallucinations are visual and auditory; however, there are others that we have told you about in this article.

    What are hallucinations

    Basically hallucinations they are perceptual experiences non-existent for the rest of the world; they only seem real to the person who experiences them. This phenomenon is much more common than most people realize, can occur in any modality of perception, and generally has 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 hallucinate because certain chemicals in drugs influence synapses (The spaces through which neurons communicate with each other) and cause activation of certain regions of the brain, for example, the parietal lobe in hallucinations of touch.

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

    However, experts say that lack of sleep can also cause this phenomenonAs it has been found that after 24 hours without sleep, a person is more likely to experience hallucinations. Likewise, being in sensory deprivation for a long time can generate visions of elements that are not really there.

      the causes

      As you can see, hallucinations can occur for a variety of reasons, and not just due to serious mental disorders like schizophrenia. Some of the most common causal factors are:

      • Drug and drug use: The use of certain psychoactive substances such as marijuana, LSD and even alcohol are factors at the origin of such experiences.
      • Illness and mental disorders: Schizophrenia is the psychopathology most associated with this phenomenon; however, other disorders and diseases like Alzheimer’s disease and dementia, bipolar disorder, Wernicke-Korsakoff syndrome, temporal lobe epilepsy (ELT), brain tumors and even Parkinson’s disease also cause hallucinations.
      • brain damage: Brain damage 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 body).

      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 happen when the person sees things that are not really there; for example, seeing an individual who does not exist. In cases such as schizophrenia, the sick person he can even have a relation with the imaginary being. Visual hallucinations can also be flashes of light or autoscopy, i.e. seeing yourself from the outside.

      2. Hearing aids

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


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

      4. Olfactory

      They are also rare and include these scent-type hallucinations. They are usually caused by drug use and are usually unpleasant smells. Sometimes they also appear in the times when it is expressed next to certain types of migraine, as well as taste and auditory.

      5. Somatic

      These hallucinations include the sensations in the body of the individual who suffers from them, who experience them as real. Some people have reported feeling like they have metallic organs, they pretended to feel like 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 water (for example, they perceive that they have water in the lungs)

      7. Paresthesias

      They belong to the previous group but are common in some disorders such as Wernicke-Korsakov. The person feels a tingling sensation, As if he had ants running through his skin. They are also common with the use of other drugs like cocaine.

      8. Kinesics

      Kinetic or kinesthetic hallucinations are those related to the movement of one’s own body. They are common in patients with Parkinson’s disease and in people who use psychoactive substances.

      According to the mode of appearance

      Depending on the mode of onset, hallucinations can be:

      9. Functional hallucinations

      are presented when one stimulus triggers another in the same sensory modality. For example, when someone hears the sound of real traffic and perceives the sound of TV news as hallucinating.

      10. Reflexes

      It is similar to the above because the person hallucinates in the presence of another stimulus. however, this stimulus does not belong to the same sensory modality.

      11. Negatives

      the person he perceives that something that really exists is not present. That is, something does not appear or see something that is not really at this time or place, but something that is disappearing.

      12. Negative autoscopies

      It is the opposite of autoscopy. If in autoscopy the person is seen from the outside as if it were a mirror, in negative autoscopy the person, when we go to look in the mirror, we do not see.

      13. Extracampinas

      It’s these hallucinations that are outside our field of vision. For example, when you perceive someone in front of you as if you are behind, or when you hear a voice that is in another city.

      14. Pseudo-hallucinations

      Pseudo-hallucinations are those in which the person he is aware that the hallucinations he is experiencing are not true. For example, when an individual perceives the voice of a deceased relative but knows that cannot be true because he passed away years ago.

      15. hypnagogic

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

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