5 The prevalence of PTSD is rather variable, and has been assessed in two ways: one approach has been to examine prevalence in the general population, whilst the other has been to examine prevalence in "high risk" groups. The Epidemiological Catchment Area(ECA) Survey estimated the lifetime prevalence of PTSD at about 1.3% in the general population, and at 3.5% in persons exposed to civilian or military violence, whilst a rate of 20% was found for veterans wounded in Vietnam (10). Another community based epidemiological study estimated the lifetime and sixmonth prevalence rates at 1.3 and 0.44% respectively (11). Those with PTSD had greater job instability, a family history of psychiatric disorder, parental poverty, and child abuse. The National Vietnam Veterans Readjustment Study reported lifetime prevalence rates of 30.9% for males and 17.5% for females, whilst,forthose exposed to high war zone stress, the current prevalence rates were 38.5% and 17.5% for men and women respectively (12). The results of community-based epidemiology thus suggests that the prevalence increases as a function of experience with trauma. In studies of "high risk" groups, a strong association is also consistently found between organised violence and psychiatric disorder, with PTSD being the most common diagnosis. The most studied high risk population has been war veterans, and studies of war veterans consistently demonstrate a relationship between the experience of violence and psychological disorder. Torture clearly represents the most extreme form of exposure to violence, in that the effects are premeditated and designed, the process usually involves attacks of both a physical and psychological nature, and, most importantly, torture has an explicitly political purpose in a clear socio-political context (13). One estimate sees "government- sanctioned torture" as being present in 78 countries in the world (14), whilst another estimate reckons that between 5% and 35% of the worlds refugees have suffered at least one torture experience (15).