Oh, also, the very DEFINITION of psychedelic drugs is
A psychedelic substance is a psychoactive drug whose primary action is to alter cognition and perception.
They are also a sub-type of hallucinogens, which are defined as
Hallucinogens are a general group of pharmacological agents that can be divided into three broad categories: psychedelics, dissociatives, and deliriants. These classes of psychoactive drugs have in common that they can cause subjective changes in perception, thought, emotion and consciousness. Unlike other psychoactive drugs, such as stimulants and opioids, these drugs do not merely amplify familiar states of mind, but rather induce experiences that are qualitatively different from those of ordinary consciousness. These experiences are often compared to non-ordinary forms of consciousness such as trance, meditation, dreams, or insanity.
So, the very purpose of taking a psychedelic drug is to alter your perception of reality and create experiences that happened only in your mind.