Shamanism is not a set of specific beliefs or written dogmas that are applicable to all cultures having shaman.
Because of this lack, shamanism may not be classified as a religion even though on a community level it may have religious overtones.
There are three areas of commonality in world shamanism.
Depending on the culture, the emphasis on any one of these three areas may differ.
The first area all shamanic cultures hold in common is the recognition of a spiritual world peopled with spiritual entities.
Second, there is worldwide agreement that there is a direct relationship of the spiritual world to ordinary reality.
Third, there is a focus on ecstasy.
Ecstasy as it is used here and by historian, Mircea Eliade is not the drug, methylenedioxymethamphetamine.
Rather, ecstasy refers to a state of emotion during which one goes beyond rational thought common to ordinary reality.
The three types of ecstasy are: shamanic ecstasy, prophetic ecstasy, and mystical ecstasy.
Briefly, in prophetic ecstasy, the prophet speaks for the divine; whereas, mystic ecstasy, the mystic comes into the presence of the divine reality.
Our interest here is only in shamanic ecstasy.
During his trance, the shaman's soul leaves his physical body, ascends upward, or descends downward into the underworld for the purpose of seeking answers to his question.
The question relates to the well-being of the shamanic patient.
Ecstasy has at least three perceptible levels: physiological, psychological, and intuitive.
It is most likely, the shaman would experience all of these levels during his trance state.
The end result is always based on the ability of the shaman to control his trance.
It's questionable if he can do that while drugged.