Post-traumatic stress disorder is unusual among DSM disorders in that the diagnostic criteria specify an aetiological event: exposure to a traumatic stressor. In their letter Elhai et al cite examples that do not meet the stressor criterion, the symptom criteria for PTSD, or the criteria of distress or impairment. The DSM-IV symptoms (re-experiencing, avoidance/numbing and hyperarousal) are defined in terms of their connection with a traumatic event. The ‘conceptual bracket creep’ (Reference McNallyMcNally, 2003) refers to the broadening of the stressor criterion in DSM-IV, especially to the inclusion of ‘second-hand exposure’, such as learning about the unexpected death of a close friend/relative or watching atrocities on television (see Reference RosenbaumRosenbaum, 2004). This seems to increase the eligible events by about 20% (Reference Breslau and KesslerBreslau & Kessler, 2001). However, more important is the question addressed in the DSM-IV guidebook ‘whether or not to include reactions to the numerous stressors that are upsetting, but not life threatening (Reference Frances, First and PincusFrances et al, 1995: p. 259) or even to eliminate the stressor criterion altogether. The fear that more inclusive definitions will vastly increase the frequency of the diagnosis seems to be unrealistic. More minor stressors simply will not result in the other diagnostic criteria for PTSD.

McNally (Reference McNally2003) makes an important point in stating that with the inclusion of such diverse events it will be difficult to identify common psychobiological mechanisms underlying symptomatic expression. In our opinion, to develop PTSD the stressor - often associated with severe sadness - should be intense enough to evoke a psychobiological dysregulation of the fear system, which results in the event being re-experienced, avoided and leading to a state of hyperarousal where the person feels that danger could strike again at any moment. This psychobiological stress response is dependent on subjective appraisal of the event and not on objective criteria of stressor severity (Reference Olff, Langeland and GersonsOlff et al, 2005). This would suggest that ‘second-hand exposure’, non-typical traumatic stressors or even life events might in some instances evoke an intense psychobiological dysregulation leading to ‘PTSD’ symptoms. Apparently, this was the case for the farmers who witnessed (saw, heard, smelled) all their animals being destroyed, an event that was beyond their control and is certainly ‘outside the range of their normal experience’.

Mental healthcare should be available to those with significant mental health problems, even if these are considered sub-threshold for PTSD. By conducting a large epidemiological survey in The Netherlands we hope to determine what kind of stressors (including life events) evoke what kind of ‘post-traumatic’ symptoms, as well as the implications for mental healthcare.