1. ¹Anxiety and Stress Research Unit, Ministry of Health Mental Health Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
2. ²The Chaim Sheba Medical Center, Sackler Medical School, Tel-Aviv University, Israel
3. ³Department of Psychology, University of Haifa, Israel

Correspondence: Dr H Cohen, Anxiety and Stress Research Unit, Ministry of Health Mental Health Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84170, Israel. Tel: +972 8 6401743; Fax: 972 8 6401742; E-mail: hagitc@bgumail.bgu.ac.il.

Received 12 January 2004; Revised 1 June 2004; Accepted 4 June 2004; Published online 14 July 2004.

Abstract

Post-traumatic stress disorder (PTSD) affects about 20–30% of exposed individuals. Clinical studies of PTSD generally employ stringent criteria for inclusion in study populations, and yet in animal studies the data collection and analysis are generally expressed as a function of exposed vs nonexposed populations, regardless of individual variation in response. Prior data support an approach to animal models analogous to inclusion criteria in clinical studies. This series of studies sought to assess prevalence rates of maladaptive vs adaptive responses determined according to a more stringent approach to the concept of inclusion/exclusion criteria (cutoff behavioral criteria—CBC), consisting of two successive behavioral tests (elevated plus maze and acoustic startle response tests). The rats were exposed to stressors in two different paradigms; exposure to a predator and underwater trauma. The prevalence rates of maladaptive responses to stress in these two distinct models dropped over time from 90% in the acute phase to 25% enduring/maladaptive response at 7 days, to remain constant over 30 days. As setting the affected individuals apart from the unaffected approximates clinical studies, it might also help to clarify some of the pending issues in PTSD research.