Post-traumatic stress disorder (PTSD) was introduced to have a single cause (i.e. traumatic event). This is unique as there is a clear, environmental cause rather than a complex interplay between environmental and genetic factors, such as in other disorders. However, not everyone who experiences trauma develops PTSD. This leads to three main criticisms towards PTSD:

1. PTSD pathologizes normal stress
   This criticism states that PTSD makes a mental disorder out of normal stress. This holds that reaction to extreme stress are time-limited (1), the symptoms of PTSD are omnipresent reactions to stressful events found in people suffering normal distress (2) and that PTSD stress is biologically not distinguishable from normal distress.
2. Inadequacy of criterion A
   
   1. Insufficient specificity of criterion A
      The A criterion is not specific enough as it includes people who learn about a trauma from others. This can lead to a diagnosis of PTSD which is detached from an actual traumatic experience.
   2. Excessive specificity of criterion A
      The A criterion is too specific as it includes the response of people in the face of trauma. However, there is a wide variety of responses and these do not exclude the development of PTSD.
   3. Other disorders are linked to traumatic events
      The A criterion assumes a unique relationship between the stressor and PTSD. However, a traumatic event also increases the risk of a disorder. It is not clear whether this also occurs independently of the increased risk for PTSD.
3. Symptoms overlap with other disorders
   There is significant symptom overlap with depression and other anxiety disorders. This means that there are many different combinations of symptoms that will yield a diagnosis of PTSD.

The reaction to extreme stress is not necessarily time-limited and there is unique brain activation in PTSD compared to other people. This means that the first criticism does not fully hold. People have developed PTSD symptoms as a result of lower intensity traumas (e.g. learning about 9/11) due to genetic vulnerability. Furthermore, prolonged stress also leads to PTSD symptoms and indirect traumas (e.g. Halloween films) do not appear to lead to the full diagnostic criteria for PTSD.

It is undesirable to specify trigger events as an individual’s symptomatic profile will be shaped by their genetics (1), environmental history (2) and an interaction of the two (3). The A criterion only describes the usual context of PTSD without contributing to its diagnosis. It may thus be best to abolish the A criterion and refocus PTSD on a smaller set of core symptoms. It should be refocused around re-experiencing the event in the present in the form of intrusive multisensory images accompanied by a marked fear or horror. Refocusing the diagnosis of PTSD leads to a greater homogeneity of cases and reduced overlap with other disorders.