Scoping review on shamanistic trances practices

Abstract

Background: Shamanism is a spiritual tradition in which trance practitioners deliberately modify their state of consciousness to seemingly interact with an invisible world to resolve their community members' problems. This review aims to provide a multidisciplinary overview of scientific research on shamanic trance.

Methods: The search was performed using PubMed and Google Scholar databases. Twenty-seven articles were found to be eligible, and their data were classified into four dimensions, namely, a) phenomenology, b) psychology, c) neuro-physiological functions, and d) clinical applications.

Results: These studies suggest that these trances are non-pathological, different from normal states of consciousness in terms of phenomenology and neurophysiology, and influenced by multiple personal and environmental variables. Furthermore, while trances may offer therapeutic potential, their scope should be approached cautiously, underscoring the need for rigorous studies to assess the effectiveness of shamanic approaches for complementary therapies.

Conclusion: Overall, shamanic trance and its potential benefits remain an intriguing and multifaceted area of scientific study, offering insights into the intersections of consciousness, spirituality, and possibly therapy.

Keywords: Brain and physiological function; Clinical applications; Phenomenology; Psychology; Shamanism; Trance.

Fig. 1

Proposed framework for trance research: Trance categories with a specific focus on shamanic trances, their lived experience and the four dimensions studied in this review

Fig. 2

Flowchart of the literature search process

Fig. 3

Main neuroimaging findings of trances: A Summary figures with the location of the main findings found in functional magnetic resonance imaging (fMRI) trance studies (N = 4) [8, 60, 74, 80]. B Psychographic experts (EXP in red) showed lower Single Photon Emission Computed Tomography (SPECT) activity during trance (condition: control (Con) vs. psychography (Psych)) compared to fewer experts (LEX in blue) who showed greater activity during trance in the orange brain areas. Adapted with permission from [80]. C fMRI activity modulation in a trance case study. C1: Blood-oxygen-level-dependent (BOLD) signal modulation in the auditory cortex (yellow box) with signal increasing when trance was self-assessed as high (dark blue) and decreasing when reported as low (gray) while listening to music (white represents the condition of resting with no music), C2: BOLD signal in the auditory cortex (yellow box) show increased signal during music (blue boxes) compared to no music (gray boxes), and in the last two blocks (bright blue), the trance was perceived as high by the subject. Adapted with permission from [74]. D Significant BOLD activation during mediumistic trance compared to resting conditions (in red) and during mediumistic trance compared to imagination (in blue). Reproduced with permission from [60]. E Mediumistic trance vs. resting brain modulation within the sensorimotor network. Reproduced with permission from [60]

Fig. 4

Main results of the scoping review divided into 4 categories