PTSD sufferers have a reduced ability to handle stressful situations. Not necessarily those same conditions related to the event that created the PTSD.
As regards your medical, a lot will depend on the severity of the PTSD, and what are the initiating factors that bring about the inability to deal with the current stress conditions.
You really need to personally examine how you would go in a high-stress situation, such as a serious in-flight incident, which threatens your life.
Your ability to deal rationally and calmly with ongoing emergency, stressful situations, may be compromised by the PTSD.