A SYMPTOM PROVOCATION STUDY OF POSTTRAUMATIC-STRESS-DISORDER USING POSITRON EMISSION TOMOGRAPHY AND SCRIPT-DRIVEN IMAGERY

Background: Previous studies have used symptom provocation and positro n emission tomography to delineate the brain systems that mediate vari ous anxiety states. Using an analogous approach, the goal of this stud y was to measure regional cerebral blood flow changes associated with posttraumatic stress disorder (PTSD) symptoms. Methods: Eight patients with PTSD, screened as physiologically responsive to a script-driven imagery symptom provocation paradigm, were exposed sequentially to aud iotaped traumatic and neutral scripts in conjunction with positron emi ssion tomography. Heart rate and subjective measures of emotional stat e were obtained for each condition. Statistical mapping techniques wer e used to determine locations of significant brain activation. Results : Increases in normalized blood flow were found for the traumatic as c ompared with control conditions in right-sided limbic, paralimbic, and visual areas; decreases were found in left inferior frontal and middl e temporal cortex. Conclusions: The results suggest that emotions asso ciated with the PTSD symptomatic state are mediated by the limbic and paralimbic systems within the right hemisphere. Activation of visual c ortex may correspond to the visual component of PTSD reexperiencing ph enomena.