Hallucinations

A hallucination is a perception in the absence of an external context stimulus that has the compelling sense of reality. They are distinguishable from several related phenomena, such as dreaming (REM sleep), which does not involve wakefulness; pseudohallucination, which does not mimic real perception, and is accurately perceived as unreal; illusion, which involves distorted or misinterpreted real perception; and mental imagery, which does not mimic real perception, and is under voluntary control. Hallucinations also differ from "delusional perceptions", in which a correctly sensed and interpre

phenomenon

Hallucinogens, also known as psychedelics, entheogens, or historically as psychotomimetics, are a broad and diverse class of psychoactive drugs that can induce altered states of consciousness characterized by marked changes in perception, mood, cognition, and self-experience, along with a range of other psychological alterations. Hallucinogens are often categorized as either being psychedelics, dissociatives, or deliriants, but not all hallucinogens fall into these three classes.

Paresthesia is a sensation of the skin that may feel like numbness (hypoesthesia), tingling, pricking, chilling, or burning. It can be temporary or chronic and has many possible underlying causes. Paresthesia is usually painless and can occur anywhere on the body, but does most commonly in the arms and legs.

serotonin receptor agonist temporarily altering states of consciousness

perception of painful and nonpainful phantom sensations that occur following the complete or partial loss of a limb

neuropsychological condition

the act of deliberately removing or reducing stimuli

An artist's representation of how some people may see phosphenes by retinal stimulation|alt=artistic representation of phosphenes|thumb A phosphene is the phenomenon of seeing light without light entering the eye. The word phosphene comes from the Greek words phos (light) and phainein (to show). Phosphenes that are induced by movement or sound may be associated with optic neuritis.

visual impairment

eye disturbance with/without headache

syndrome where people perceive loud imagined noises when falling asleep or waking up

shared psychosis, a psychiatric syndrome in which symptoms of a delusional belief are transmitted from one individual to another

Hypnagogia is the transitional state from wakefulness to sleep, also defined as the waning state of consciousness during the onset of sleep. Its corresponding state is ‌sleep to wakefulness. Mental phenomena that may occur during this "threshold consciousness" include hallucinations, lucid dreaming, and sleep paralysis.

phenomenon where a friendship or other interpersonal relationship takes place in imagination

any condition which is significantly different from a normal waking state

Supposed paranormal phenomenon

In traditions of mysticism and the paranormal inspired by Tibetan Buddhism, a tulpa is a materialized being or thought-form, typically in human shape, that is created through spiritual practice and intense concentration. The term is borrowed from the Tibetan language. Modern practitioners, who call themselves "tulpamancers", use the term to refer to a type of willed imaginary friend whom practitioners consider sentient and relatively independent. Modern practitioners predominantly consider tulpas a psychological rather than a paranormal phenomenon. The idea became an important belief in theoso

major depressive episode that is accompanied by psychotic symptoms

visual disturbances and the experience of complex visual hallucinations in a blind person

mental disorder

non-psychotic disorder after a previous use of drugs

hearing sounds without finding external stimuli, but having the characteristic of actually hearing sounds

altered state of consciousness brought upon by the consumption of psychoactive substances

Photopsia is the presence of perceived flashes of light in the field of vision.

visual aura

Perception that one's mobile phone is vibrating or ringing when it is not

Concept in human perception of sound

Phantosmia (phantom smell), also called an olfactory hallucination or a phantom odor, is smelling an odor that is not actually there. It can occur in one nostril or both. Unpleasant phantosmia, also called cacosmia, is more common and is often described as smelling something that is burned, foul, spoiled, or rotten. Experiencing occasional phantom smells is normal and usually goes away on its own in time. When hallucinations of this type do not improve on their own or when they keep coming back, it can be very upsetting and can disrupt an individual's quality of life.

A pseudohallucination (from + hallucination) is an involuntary sensory experience that is vivid enough to be perceived as a hallucination, but is recognised by the individual as subjective and lacking objective reality.

range of phenomena reported by dying people

Formication is the sensation resembling that of small insects crawling on (or under) the skin, in the absence of actual insects. It is one specific form of a set of sensations known as paresthesias, which also include the more common prickling, tingling sensation known as pins and needles. Formication is a well-documented symptom which has numerous possible causes. The word is derived from formica, the Latin word for ant.

psychological phenomenon

type of hallucination

in the Catholic Church, a revelation from God to a specific Christian

hallucinogenic salve used in witchcraft to enable flight

type of hallucination; seeing things that aren’t actually there

name given to a supernatural creature, used to explain the phenomenon of sleep paralysis

hallucination in the absence of obvious physical or psychological triggers (fatigue, psychoactive substances, mental illness etc.)

condition of pain in a lost eye

Prosopometamorphopsia (PMO), also known as demon face syndrome, is a neurological disorder characterized by altered perceptions of faces. In the perception of a person with the disorder, facial features are distorted in a variety of ways including drooping, swelling, discoloration, and shifts of position.

neurological disorder

auditory hallucination associated with hearing loss