1. History of Axis I psychiatric diagnosis (other than as specified), e.g., psychotic disorder, bipolar disorder, obsessive compulsive disorder (OCD), tic disorder, or eating disorder. Note that comorbid current major depressive disorder will be allowed in up to one half of the PTSD group. This will enable inclusion of this common comorbidity, but also enable an assessment of whether or not the presence of this comorbid diagnosis is driving any observed significant between-group differences.