Attention and regional cerebral blood flow in posttraumatic stress disorder patients with substance abuse histories.

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