Shamanic Practices of the Past
There seems to be a direct connection between the ancient shamanic practices and the process of individuals under going what is called Bi-polar disorder. The similarities between the 'calling' of a shaman of the past aligns perfectly with the experiences of the modern day individual labeled Bi-polar.
Many past religious experiences that have been written about have direct parallels to the modern day diagnosed psychotic experience. Whether Jesus or Mohammed, their experiences if happened in todays society would be labeled as mental illness.
Anyone working with bi-polar individuals are well aware of the individuals pre-occupation with religious concepts and their alignment with a religious figure.
Carl Jung work on the process of individualization also compares to the psychological upheaval experienced in the individual diagnosed as bi-polar. There is a breakdown of the Ego structure which had been holding the unconscious material in check. The person now becomes overwhelmed by the unchecked raw power unconscious content.
Modern Day Ignorance
The modern day psychologists are either ignorant or just to afraid to identify the markers. For those pioneers that came before them, Jung, Perry, Szasz, and Laing, who actually understood the process were shunned by their peers and community for going against the status quo.