Preceding all organized religion, shamanism is, in itself, is not a religion. Because shaman complies with the belief that there is a direct relationship between healing and the spiritual world is easy to equate shamanism as a religion.
Shamans act as an intermediary between the natural world and the spiritual world. Although some claim shamanism is not a sect. Admittedly, some have associated themselves cult for some basic shamanic practices. You can find best retreats, shamans, therapists near your area.
It seems that the interest here is the use of hallucinogenic drugs. It is doubtful if the user actually brings an understanding of reality or uses their energy to heal someone.
A shaman communicates with the spiritual world for several reasons. Among other things, the primary one is to heal the sick soul. Others include reading the future; ask for success in a particular business, or to function as a psychopomp.
Whatever it is that must be resolved, healer connects with the axis Mundi to create a special relationship with the Spirit and in some cases, actually gain control over them.
Despite rumors and myths, in general, a shamanic practitioner is not involved in bringing about the dangers of 'evil' with someone.
Quackery is not a specific set of beliefs instilled in a uniform system organized around the world. This does not mean there is no similarity. The main similarity is the recognition of the spiritual world and the existence of spirits.