Higher brain blood flow at amygdala and lower frontal cortex blood flow inPTSD patients with comorbid cocaine and alcohol abuse compared with normals

Posttramatic stress disorder (PTSD) patients with histories of cocaine and alcohol abuse (CA-PTSD) were compared with normal volunteers. Positron emis sion tomography (PET) scans with O-15-butanol were used to compare regional cerebral blood flow (rCBF) between the groups during rest and during an au ditory continuous performance task (ACPT). CA-PTSD patients had significant ly higher rCBF in right amygdala and left parahippocampal gyrus than normal s during the ACPT. Normals had higher rCBF at frontal cortex during the res ting scan and during the ACPT. The role of the amygdala in attention and fe ar conditioning suggests that increased amygdala rCBF may be related to cli nical features of PTSD. Cocaine use may be associated with increased amygda la rCBF in PTSD patients. Amygdala and frontal cortex attention system comp onents may be reciprocally related and their relative contributions to proc essing of neutral stimuli perturbed in CA-PTSD.