Portions of the following are based on material from the most excellent book "The Shaman's Doorway: Opening Imagination to Power and Myth" by Stephen Larsen. I found this material very early in my shamanic path. It has stood the test of time for me.
The definition of mental disorder, or illness, is made at the society level. Western medicine has categorized and quantified mental disorders. Those matching the "symptoms" are considered ill. Treatment by medication or processing is prescribed. The person is considered cured when the symptoms subside.
What is a person to do when they see things others don't, or talk to beings that others cannot hear? I advise people to NOT tell the medical people this. The answer to the question, "do you hear voices?" is a direct NO. (smile) By nature, the shamanist leaves themselves open to interaction with other people. The shamanist's peers or 'tribe' benefit from the shamanist's pursuits. These people understand the other-world communication of the shamanist. What about others? How can the shamanist be judged by a larger society? Stephen Larson offers the following benchmarks of acceptance:
1) Orthodox acceptance: appointed local seer, oracle or saint.
2) Unorthodox popular acceptance: prophet, evangelist, radical reformer.
3) Unorthodox unpopular acceptance: madman – ignored and locked up.
An orthodox or popular unorthodox acceptance indicates a transpersonal message. What is transpersonal? This means that the message is received and understood by others.
Larson offers the following questions as a check of "validity" for a person's message:
1) What does the particular belief mean for this particular individual?
2) How does it function in the context of the rest of his life?
3) Is what appears to be a transpersonal message good for everyone, or maybe only meant for the individual?
The more disconnected the message, the more subjective and purely private someone’s world can be. The excessively personal message indicates a state approaching what could be better called mental illness. Of these, paranoid schizophrenia is most difficult to cure of all schizoid disorders: the paranoid projects their unique inner landscape on the outside world, entirely losing the ability to differentiate projection from actuality. The person loses the ability to communicate their inner landscape in a transpersonal manner.
To illustrate this point, Larson shares a story about Ram Dass (Richard Albert) visiting his brother in a mental institution. The brother was a ward because of his belief that he was Jesus Christ. Ram Dass, dressed in full Hindu guru garb, was outwardly the odd-man. His brother looks at Ram Dass, and in a moment of clarity, asks “and why am I the one that is locked up?” It is OK to look strange. It is OK to act strange. The measure of compatibility with a group is the acceptance by that group. The shamanist and Shaman both fit into their group, no matter their relative degree of oddity.
In the end, the shamanist and Shaman are challenged to communicate a transpersonal message to their charges. They are called to be an oracle, psychopomp (soul conductor) and healer. The larger society may have it's own judgment, but the inner vision of unseen things is to be shared in a way that both informs and helps the 'tribe'.