Familial psychiatric illness and posttraumatic stress disorder: Findings from a family study of substance abuse and anxiety disorders

Background. Aside from the possibility of a direct relationship between individual and familial posttraumatic stress disorder (PTSD), there is accumulating evidence that implicates a family history of psychiatric and substance use disorders as an important risk factor in the development of PTSD and associated symptoms. Method: The familial risk of DSM-III-R PTSD was examined within a family study of clinical- and community-ascertained probands (N = 263) and their 1206 adult first-degree relatives. Results: Although PTSD among probands was not found to significantly elevate the risk of PTSD among first-degree relatives, an elevated rate of PTSD was found among the relatives of drug abusing probands compared with the relatives of probands with alcoholism, other anxiety disorders, and normal controls. Additionally, affective disorders were significantly associated with PTSD in relatives (p < .01). When these familial and individual associations were examined according to gender, drug disorders in probands were significantly associated with PTSD only among mate relatives (p < .01), while the association between PTSD and comorbid affective disorders was seen primarily among female relatives (p < .01). Conclusion: Although probands in the present family study were not selected specifically for PTSD, the data afforded a unique opportunity to examine the profile of familial psychopathology as a part of the complex picture of susceptibility for PTSD. Future family study research will be able to determine the generalizability of the present findings through more complete measurement of diverse forms of trauma.