These excerpts come from a cool book that I requested from UC Berkeley, so I have to return it soon. The author earned an MPH and PhD and spent most of his career studying the biological bases for traditional healing practices, especially shamanism. He is a retired professor of Arizona State University and lives in Brazil. His website is at www.michaelwinkelman.com.
"A basic mechanism in shamanistic healing involves symbolic healing, particularly the use of natural metaphors that represent intrapsychic dynamics and provide a means of producing psychosocial and emotional integration." (p. 184)
"...use of spirit beliefs as representations that provide psychosocial, psychocognitive, emotional and projective mechanisms." (p. 183)
"Neuropeptides and neuroreceptors function as an information network that links body and mind through emotions." (p. 183)
Opioid release stimulates emotional experience and emotional experience stimulates opioid release. (p. 183)
"A biopsychosocial dynamic...produces symbolically induced biological changes by eliciting endogenous healing responses and other recuperative potentials." (p. 183)
"Socialization links symbols and physiological processes, providing a mechanism for ritual therapies to manipulate physiological processes through their relationships with symbols that were established through socialization; this relationship enables them to entrain physiological processes and to produce affective responses. (183-4)
"Spirit manipulation and the mind-body interface play a central role in the management of emotion states particularly anxiety, fear and attachment." (p. 183)
"The community ritual dynamics of shamanic healing also elicit endogenous healing responses. The symbolic and ritual aspects of shamanistic healing practices provide therapeutic mechanisms that elicit the opioid systems and produce psychological and sociophysiological effects related to attachment and bonding. A neurological basis for ritual structure is illustrated by the cross-cultural similarities in the characteristics of ritual and their homologies with obsessive-compulsive disorder. This illustrates that one basis for shamanistic healing lies in manipulation of the processes of the R-complex (reptilian brain) and the paleomammalian brain." (p. 184)
Winkelman, Michael M. (2010). Shamanism: A Biopsychosocial Paradigm of Consciousness and Healing. Santa Barbara: Praeger.