Preliminary report: Brain blood flow using PET in patients with posttraumatic stress disorder and substance-abuse histories

Posttraumatic stress disorder (PTSD) is defined by DSM-III-R as an anxiety disorder characterized by recurrent distressing and intrusive remembrances of a traumatic event (American Psychiatric Association 1987). Some physiological abnormalities have been found in PTSD, notably for cardiac (Blanchard et al 1991) and neuroendocrine measures (Friedman 1991), but no studies to date have directly measured regional brain function changes in PTSD using positron emission tomography (PET). This preliminary study compares PTSD patients who have histories of substance abuse (Keane et al 1983, 1988) with normal controls who did not have a history of substance abuse. PET studies of anxiety disorders (Baxter et al 1987; Nordahl et al 1989, 1990; Reiman et al 1986), and acute (London et al 1990) and recent (Volkow et al 1991) substance abuse suggested hypotheses of increased orbital frontal cortex (OFC) blood flow and decreased left/right hippocampal ratios in PTSD patients with histories of substance abuse (PTSD-SA) compared to normal control subjects.