The term psychedelic is derived from the Greek words ψυχή (psyche, "soul") and δηλείν (delein, "to manifest"), translating to "mind-manifesting". A psychedelic experience is characterized by the perception of aspects of one's mind previously unknown, or by the creative exuberance of the mind liberated from its ostensibly ordinary fetters. Psychedelic states are an array of experiences elicited by sensory deprivation as well as by psychedelic substances. Such experiences include hallucinations, changes of perception, synesthesia, altered states of awareness, mystical states, and occasionally states resembling psychosis.
The term was first coined as a noun in 1957 by psychiatrist Humphry Osmond as an alternative descriptor for hallucinogenic drugs in the context of psychedelic psychotherapy. Timothy Leary, who was largely responsible for the popularization of the term "psychedelic", was a well-known proponent of their use, as was Aldous Huxley. However, both advanced widely different opinions on the broad use of psychedelics by state and civil society. Leary promulgated the idea of such substances as a panacea, while Huxley suggested that only the cultural and intellectual elite should partake of entheogens systematically.
The use of psychedelic drugs became widespread in the modern West in the mid-1960s.
The impact of psychedelic drugs on western culture in the 1960s led to semantic drift in the use of the word "psychedelic", and it is now frequently applied to describe any brightly patterned or colored object. In objection to this new meaning, and to what some consider pejorative meanings of other synonyms such as "hallucinogen" and "psychotomimetic", the term "entheogen" was proposed and is seeing increasing use. However, many consider the term "entheogen" best reserved for religious and spiritual usage, such as certain Native American churches do with the peyote sacrament, and "psychedelic" left to describe those who are using these drugs for recreation, psychotherapy, physical healing, or creative problem solving. In science, hallucinogen remains the standard term.
At the same time as psychedelic drugs were being used by the counterculture of the 1960s, they were also being used in experiments by governments, who saw them and sensory deprivation as useful agents for mind control; see MKULTRA for the CIA involvement in the use of psychedelic drugs.
One of the first uses of the word in the music scene of this time was in the 1964 recording of "Hesitation Blues" by the Holy Modal Rounders. The term was introduced to rock music and popularized by the 13th Floor Elevators 1966 album The Psychedelic Sounds of the 13th Floor Elevators.
Many artists in the late 1960s and early 1970s attempted to illustrate the psychedelic experience. One example of this experimentation is seen in Mati Klarwein's painting Annunciation, which was used as the cover art for Santana's Abraxas. The cover of Pink Floyd's 1968 album A Saucerful of Secrets is also of this type. The cover of Oasis' 2008 album, Dig Out Your Soul, also has a psychedelic album cover, with a slightly muted color scheme.
The fashion for psychedelic drugs gave its name to the visual style of psychedelia, a term describing a category of rock music known as psychedelic rock, visual art, fashion, and culture that is associated originally with the high 1960s, hippies, and the Haight-Ashbury neighborhood of San Francisco, California. Psychedelia generally began in 1966, but truly took off in 1967 with the Summer of Love. Although associated with San Francisco, the style soon spread across the US, and worldwide.
The counterculture of the 1960s had a strong influence on the popular culture of the early 1970s, and is well recognized even by those who are naïve to its psychedelic origins. It later became linked to a style of electronic dance music commonly known as psychedelic trance.
The word psychedelic is a word invented in the 20th century by joining the Greek words for "mind," ψυχή (psyche), and "manifest," δήλος (delos).
A person in a "psychedelic state" is supposed to be able to feel new ways of looking at his mind that were unknown to him before. This can be caused by taking psychedelic drugs, like LSD. In medicine, the new feelings a patient has when he is in psychedelic state are called hallucinations and synesthesia; these are also seen in patients with psychosis.