Hallucinations

     hallucinations can be produced by a chemical imbalance of the brain's neurotransmitters, such as happens in patients who suffer from schizophrenia.  Or they can be induced by substances that are called hallucinogenic, or capable of inducing hallucinations such as LSD or marijuana. Or else they can be caused by sleep-deprivation. Hallucinations might also be caused by  caused by cerebral neurotransmitter imbalances.

: a substance (such as norepinephrine or acetylcholine) that transmits nerve impulses across a synapse




     Hallucinogens are a class of psychoactive substances that act on the nervous system to alter perception, mood, and various cognitive processes.[citation needed] Hallucinogens represent one of the three major classes of psychoactive substances: the other two are stimulants ("uppers") and depressants ("downers"). However, hallucinogens are claimed to be distinct from stimulants and depressants in that they do not merely amplify or dull existing states of consciousness, but instead produce qualitatively unique states in which the environment and self are perceived in a new fashion.



     Notably, hallucinogens are commonly reported to facilitate self-understanding and self-discovery. Hallucinogenic experiences are often compared to non-ordinary forms of consciousness such as lucid dreaming, meditation, religious, mystical or trans-personal experiences, hallucinations, and states of psychosis.



     

     Each category is associated with a unique mechanism of action, subjective effects, therapeutic potential, and health risks. It is highly advised to use harm reduction practices when using these substances.

psychonautwiki.org/wiki/Hallucinogens

     Visual; A visual hallucination is one that a person sees. Certain American Indians sought such hallucinations because they considered them messages from a spirit world.  Sitting bull claimed to have had one prior to the Battle of the Little Big Horn.


     Auditory : This involves hearing things that are not being externally produced. It can involve just sounds or else voices which might be garbled or clear. 


     Olfactory: This involves smells either pleasant or repugnant.


     Tactile: The person feels that he or she is being touched or else experiences sensations involving touch that are totally unwarranted by reality.  Pressure, smoothness, roughness, pain, pleasure.


     Gustatory: This involves taste.  The brain can generate:  saltiness, sweetness, bitterness, sourness, rottenness, all on its own without any external input.