Altered states of consciousness generally include alterations in both the content and functioning of the consciousness, usually experienced by an individual and observed by others watching him. The term "state" is not to be trivialized but denotes the states or stages of behavior through which the individual progresses. Frequently persons in these states appear to be in a sleeplike condition commonly referred to as a trance.
Among the long term effects are the radical shifts in the perception in one's self and environment that result in a semi-permanent redefinition of one's self, world, and values. Frequently altered states of consciousness either are induced personally or by others which may or may not produce lasting effects. Some religious groups do seek to induce such altered states in persons so they may derive spiritual insight and value changes from them. The most dramatic examples of these states are mystical experiences.
When used in occult and mysticism term trance usually denotes an altered state of consciousness. A supreme example of a trance like state in occultism, particularly in Neo-pagan witchcraft, is witnessed in the ceremony of the "Drawing Down the Moon". In an altered state of consciousness the high priestess assumes the spirit of the Goddess. Within this state energy, which is believed to be the power of the Goddess, is raised. Often it is believed that the Goddess inspiringly speaks through the high priestess.
In a similar ceremony called "Drawing Down the Sun" or "Drawing Down the Horned God" the Horned God is similarly invoked in a same manner as described in the "Drawing Down the Moon". The high priest enters an state of altered consciousness in which he assumes the spirit of the Horned God.
In mysticism the altered state of consciousness may be total or partial. When partial, the state of consciousness is usually only a feeling. Most generally this feeling is one of unity with God, or the universe, or of enlightenment. Most mystics do not believe in the transcendence (see Immanence) of God. They generally subscribe to one of two theories concerning Divine Reality: emanation or immanence. From the emanation viewpoint the universe and everything in it is an outflowing from God, while the immanence view holds that the universe is not a projection from God, but rather, it is immersed in God.
The experience of being united with God or nature is called a mystical experience. Such experiences may be of a religious or nonreligious nature. The nonreligious experiences derive much of their content from nature; although many religious mystics have been lead to God or the Absolute through nature. However, not all transcendental experiences with nature are mystical, but just render feelings of overwhelming joy or ecstasy.
Causes other than religious beliefs, such as illnesses and accidents, can result in altered states of consciousness or mystical experiences. "In 1971 John, a graphic designer in his late thirties, smashed his legs in a motorcycle accident. `When I regained consciousness' [he said] `I looked at a tree in a certain way.' He became a pagan, and with five years had developed a `language' with trees (this was a sort of divinatory system) and he founded a Druidic order which now has 150 members (by subscription), a journal with a circulation of 750, and an inner group." The accident could have caused a mystical experience because great pain can release a neurochemical response. At least, it seemed so to this person who emphatically states the formation of his order is the direct result of the accident.
Emanuel Swedenborg (1688-1772), the Swedish scientist and scholar, also claimed to have experienced mystical experiences in the form of dreams. These episodes began at the age of fifty-six. In these dreams he traveled to spiritual planes such as heaven and hell where he claimed to have spoken with Jesus, and God, and spirits of the dead which he referred to as angels. Also, he claimed to have seen the order of the universe. He continued spending most of the remainder of his life taking these spiritual journeys usually in a light sleep or trance which sometimes lasted as long as three days. As a result of these trips his spiritual views differed greatly from orthodox Christianity. His views were published in several books.
Swedenborg's techniques of achieving the state of altered consciousness or trance were introduced into spiritualism. One individual that actively participated in this introduction was Andrew Jackson Davis, an American and a student of Swedenborg. He is said to have paved the way from mesmerism to spiritualism. Spiritualism had larger followings in the United Kingdom than the United States because of many churches. It had no legal status before 1951 when the final Witchcraft Act (of 1735) was repealed. Under that act it was possible for a medium to be charged with witchcraft.
Edgar Cayce (1877-1945) sometimes called the "sleeping prophet" gave prophetic, healing, and karmic readings in a light-sleep state similar to that of Swedenborg. Cayce put himself into a hypnotic trance while lying down and then gave personal readings. He helped heal many persons this way by describing their ailments and then prescribing what the person should do in the form of treatment. He gave many karmic readings telling about the lost continent of Atlantis and other ancient places. Frequently when giving solitary readings Cayce would have the person taking down his reading tap him to prevent him from going into a deeper sleep.
Also within shamanism altered states of consciousness are employed. They are often self-induced by the shaman and called the shamanic state of consciousness. This is a state can vary from a light sleep to a coma which enables the shaman to see and do things in a nonordinary reality which he cannot do in the ordinary reality of a waking state. It is in this nonordinary reality the shaman can perform cures with the help of guardian spirits and spirit helpers and do shape shifting
Various societies and groups have and do use hallucinogenic drugs to induce altered states of consciousness. Such drugs can be dangerous and causes long termed effects.