A pocket of very high suicide rates in a non-violent, egalitarian and cooperative population of South-East Asia

Background Extremely high rates of suicide localized within subgroups of populations where suicide is rare have been reported. We investigated this intriguing observation in a population of South-East Asia, where local culture should theoretically be preventative of suicide. Method A team including an anthropologist and a psychiatrist surveyed all cases of suicide that had occurred over 10 years in four isolated regions. A psychological autopsy was carried out comparing each suicide case with two matched control cases. Results In a region of 1192 inhabitants, 16 suicides occurred, leading to an annual suicide rate of 134/100000 which is 10 times the rate in the USA or Canada. By contrast, three ethnically similar distant communities showed low to null rates. The gender ratio was three males to one female and two-thirds of cases were aged below 35 years. Methods of suicide were poisoning and hanging and motives mainly included interpersonal discord. The pattern of developmental and clinical risk factors was somewhat different from Western countries, showing no childhood maltreatment, only one case of alcohol/substance abuse and impulsive-aggressive personality but elevated rates of social anxiety. Suicide cases had very high frequencies of second-degree biological relatives who committed suicide. Conclusions Our study confirms a persistent phenomenon of high suicide rates restricted to a subgroup of a pre-industrialized population. We hypothesized this might be explained by isolation and endogamy, which may have promoted the selection/amplification of genetic vulnerability factors, or a contagion effect. These findings shed light on suicide from both a singular and a universal perspective, suggesting that particular local conditions may significantly modulate the rate of this complex behavio