Gender differences in animal models of posttraumatic stress disorder

Epidemiological studies report higher prevalence rates of stress-related disorders such as acute stress disorder and post-traumatic stress disorder (PTSD) in women than in men following exposure to trauma. It is still not clear whether this greater prevalence in woman reflects a greater vulnerability to stress-related psychopathology. A number of individual and trauma-related characteristics have been hypothesized to contribute to these gender differences in physiological and psychological responses to trauma, differences in appraisal, interpretation or experience of threat, coping style or social support. In this context, the use of an animal model for PTSD to analyze some of these gender-related differences may be of particular utility. Animal models of PTSD offer the opportunity to distinguish between biological and socio-cultural factors, which so often enter the discussion about gender differences in PTSD prevalence. In this review, we present and discuss sex-differences in behavioral, neurochemical, neurobiological and pharmacological findings that we have collected from several different animal studies related to both basal conditions and stress responses. These models have used different paradigms and have elicited a range of behavioral and physiological manifestations associated with gender. The overall data presented demonstrate that male animals are significantly more vulnerable to acute and chronic stress, whereas females are far more resilient. The stark contradiction between these findings and contemporary epidemiological data regarding human subjects is worthy of further study. The examination of these gender-related differences can deepen our understanding of the risk or the pathophysiology of stress-related disorders.