Family and past history of mental illness as predisposing factors in post-traumatic stress disorder.

BACKGROUND

Family studies of post-traumatic stress disorder (PTSD) have given inconsistent results to date. Identifying predisposing factors in PTSD compared to anxiety disorders may help to clarify the classification of PTSD as a diagnostic entity.

METHOD: Retrospective case note study of 87 PTSD patients who participated in an RCT, and 51 PTSD patients and 87 agoraphobics treated routinely in outpatients.

RESULTS

Compared to agoraphobics, PTSD patients had significantly less family history of anxiety disorder but not mental illness in general. They also had significantly less personal history of mental illness prior to the index episode.

CONCLUSIONS

Trauma precipitated PTSD in subjects who had significantly fewer premorbid predisposing factors than did agoraphobics. Such factors may predispose agoraphobics to become psychiatrically ill after more minor trauma. Research is needed to systematically compare the events which precipitate PTSD as opposed to agoraphobia and other anxiety disorders.