Since ancient times...

...there have existed procedures capable of carrying people to exceptional states of consciousness in which the greatest mental amplitude and inspiration is juxtaposed with the dulling of the normal faculties. As the importance of these phenomena began to be understood, explanations and techniques were perfected with the intention of giving direction to processes that, in principle, were uncontrolled. Throughout history, in diverse cultures (frequently in the shadow of religions), mystical schools developed that practiced their particular ways of accessing the Profound.