Although
selective serotonin reuptake inhibitors (
SSRIs) are reported to be effective in decreasing
posttraumatic stress disorder (
PTSD) symptoms, a subgroup of
PTSD patients remain chronically symptomatic and maintain conditioned fear responses to traumatic stimuli. In this context, the establishment of an appropriate animal model of
PTSD is necessary to promote better understanding of the mechanisms of the disorder and to facilitate the development of more effective therapeutic alternatives to
SSRIs. Although no single widely accepted animal model of
PTSD has been established to date, the single prolonged stress (SPS) animal model has been partially validated as a model for
PTSD. SPS rats mimic the pathophysiological abnormalities and behavioral characteristics of
PTSD, such as enhanced anxiety-like behavior and
glucocorticoid negative feedback, and they exhibit the expected therapeutic response to
paroxetine on enhanced fear memory. In addition, SPS rats exhibit enhanced freezing in response to contextual fear conditioning, and impaired extinction of fear memory, which is alleviated by D-
cycloserine. The enhanced consolidation and impaired extinction of fear memory found in SPS rats suggests that this model has additional value because recent studies of
PTSD indicate that memory abnormalities are a central feature. In this study, we summarize the behavioral and pathophysiological
PTSD-like symptoms in SPS, focusing on memory abnormalities, and evaluate the validity of SPS as an animal model of
PTSD.