Dose-effect relationships of trauma to symptoms of depression and post-traumatic stress disorder among Cambodian survivors of mass violence

Background The dose-effect relationships of cumulative trauma to the psychi atric symptoms of major depression and post-traumatic stress disorder (PTSD ) in a community study of Cambodian survivors of mass violence were evaluat ed. Method In 1990, a survey of 1000 households was conducted in a Thai refugee camp (Site 2) using a multi-stage random sampling design. Trauma his-tory and psychiatric symptoms were assessed for two time periods. Analysis used linear dose- response regression modelling. Results 993 Cambodian adults reported a mean of 14 Poli Pot era trauma even ts and 1.3 trauma events during the past year. Symptom categories of depres sion, PTSD, dissociative and culturally dependent symptoms exhibited strong dose-effect responses with the exception of avoidance. All symptom categor ies, except avoidant symptoms, were highly correlated. Conclusions Cumulative trauma continued to affect psychiatric symptom level s a decade after the original trauma events. The diagnostic validity of PTS D criteria, with the notable exception of avoidance, was supported. Inclusi on of dissociative and culturally dependent symptoms increased the cultural sensitivity of PTSD.