An entheogen is a psychoactive substance that leads to changes in consciousness, mood, perception, and behavior. Typically, this type of substance is closely related to a religious or spiritual ceremony, such as those that are closely tied to Native American and Indigenous populations. A shaman is usually responsible for building people during the religious ceremony to ensure people are having a beneficial experience. A lot of the ceremonies involving these types of substances are designed to help people achieve transcendence and divination through yoga, sensory deprivation, meditation, and asceticism. Many of these substances fall into a special category of controlled substances, allowing indigenous populations to use them if they play an important role in a religious ceremony or spiritual event.