PROJECT ABSTRACT A small but significant percentage of people that experience a traumatic, life-threatening, event develop a condition called Post-Traumatic Stress Disorder (PTSD), which is characterized by heightened anxiety and disturbed fear processing. The condition is more prevalent in women. Additionally, PTSD is highly comorbid with other psychiatric conditions notably alcohol abuse. We have developed an animal model that captures many of the features of PTSD and as such should be helpful in developing an understanding of the biological changes that produce the disorder and suggesting novel treatments. Here we propose to use a milder stress than we have used in our published work because it produces enhanced fear learning in a smaller proportion of animals (18%) that better approximates the rate of PTSD in humans. The rats subjected to this stress will be tested on a number of measures of anxiety, altered fear processing and alcohol intake. We will use this as a tool to understand how PTSD symptoms group together to form subtypes and how these subtypes relate to the brain changes that cause maladaptive behavior.