In a systematic case-control study of 384 Nepalese adolescents aged 11-18 from 12 public schools, 194 students affected by mass psychogenic illness (MPI) were compared with 190 unaffected controls. MPI is understood as a dissociative phenomenon spread through social contagion among those prone to dissociation. Bivariate analyses linked caseness to childhood physical neglect and abuse, living in nuclear families, peritraumatic dissociation, dissociative tendencies, and depressive and post-traumatic stress symptoms. Hypnotizability was the strongest correlate among cognitive and personality traits. However, multivariable logistic regression found that common correlates of dissociation did not predict caseness, suggesting these factors do not adequately explain MPI. A Classification and Regression Trees analysis indicated that highly hypnotizable adolescents with high peritraumatic dissociation had a 73% probability of being a case.
Spirit possession in a Nepali village is a multidimensional phenomenon that cannot be reduced to a psychiatric diagnosis. A mixed-method study compared women who had experienced possession with those who had not: possessed women reported higher rates of traumatic events and more symptoms of anxiety (68% vs. 18%), depression (41% vs. 19%), and PTSD (27% vs. 0%). However, qualitative interviews with possessed individuals, family members, and traditional healers showed they did not view possession as mental illness; instead, it was seen as a form of communication with spirits and an idiom of distress expressing suffering related to mental illness, violence, trauma, and oppression. Clinical efforts must consider socio-cultural context to avoid harm.