Predating all organized religions, shamanism is, unto itself, not a religion.
Because shamans adhere to a belief that there is a direct connection between healing and the spiritual world it easy to equate shamanism as a religion.
Shaman and shamanka (the female counterpart) act as an intermediary between the natural world and the spiritual world.
Despite some claims shamanism is not a cult.
Admittedly, some have linked themselves in a cult-like fashion to some of the fundamental shamanistic practices.
It appears the interest here is the use of hallucinogenic drugs.
It's doubtful if their use actually brings about an understanding of reality or the use of their energy to heal someone.
A shaman communes with the spiritual world for several reasons.
Among these, the primary one, is to heal a sick soul.
Others include the reading of the future, asking for success in specific endeavors, or to function as psychopomp.
Whatever it is that is to be accomplished, the shaman connects with the axis mundi to create a special relationship with the Spirits and in some instances, actually gaining control over them.
Despite rumors and myth, generally speaking, a practitioner of shamanism is not involved in bringing about harm or 'evil' to someone.
Shamanism is not a specific set of beliefs that are inculcated in an organized uniform system throughout the world.
This does not mean there are not similarities.
The primary similarity being a recognition of a spiritual world and the existence of spirits.
Specific ceremonies, chants, and training are not held on a universal plane.
Norman W Wilson, PhD