ABSTRACT
Rachel Yehuda (1999) remarked, ‘One of the critical problems in trying to understand the biology of PTSD is to address the issue of why only a proportion of trauma survivors develop a particular set of responses.’ One part of the answer is likely to be genetic variance. Genetic research into psychiatric disorders is difficult at the best of times, but the requirement for research subjects to have suffered extraordinary stressors before family and twin studies can be undertaken, makes it even more so. PTSD is likely to involve multiple genes given the diversity of defences represented, learning, memory, preparedness and many other factors involved. Preliminary findings from twin studies strongly suggest heritability but these studies have not distinguished between genetic influences on trauma exposure versus that on PTSD as a reaction and type and severity of traumas have not been examined (Koenen 2003).
