ATTENTION AND REGIONAL CEREBRAL BLOOD-FLOW IN POSTTRAUMATIC-STRESS-DISORDER PATIENTS WITH SUBSTANCE-ABUSE HISTORIES

Performance on an attentional task was assessed in posttraumatic stres s disorder patients with substance abuse histories (PTSD-SA). Positron emission tomography (PET) was used to measure concurrent regional cer ebral blood flow (rCBF). Eight male PTSD-SA patients and eight normal subjects each received three serial PET scans with O-15-labeled water under the following conditions: (1) resting, (2) auditory continuous p erformance task (ACPT1), and (3) repeat auditory task (ACPT2). PTSD-SA patients made more errors of commission on the ACPT than normal subje cts. Examination of right frontal and parietal cortex ACPT task substr ates revealed decreased parietal blood flow in PTSD-SA, which may repr esent a pathophysiology for poor attentional task performance in PTSD- SA. Attentional problems may underlie other symptomatology in PTSD.