7. Subjects with a current or past history of other axis I disorders like schizophrenia, schizoaffective disorder, bipolar disorder or dementia will be excluded from the study. However, those with a comorbid history of other Axis 1 disorder like major depression, dysthymia or panic disorder will be included in the study. Justification: Approximately 70% of subjects with PTSD have comorbid depression and or alcohol abuse; reviewed in 134. Restricting the sample to PTSD patients without depression will not accurately reflect the biology of this disorder].