Psychiatry 76(3) Fall 2013 241 © 2013 Washington School of Psychiatry Sharon Dekel, Ph.D., is affiliated with the PTSD Research Laboratory, Massachusetts General Hospital-East, Charlestown, Massachusetts. Zahava Solomon, Ph.D., is affiliated with the Bob Shapell School of Social Work, Tel Aviv University, Tel-Aviv, Israel. Tamar Peleg, Ph.D., is with the Department of Social Work, Ben Gurion University of the Negev, Israel. This study was supported by the Young Investigator Grant of the Brain and Behavior Research Foundation spon- sored by Dr. Dylan Tauber, which was awarded to Sharon Dekel. Address correspondence to Sharon Dekel, PTSD Research Laboratory, Massachusetts General Hospital-East, 120 Second Ave., Charlestown, MA 02129. E-mail: dekel.sharon@gmail.com PTSD and Negative Cognitions Dekel et al. The Relationship of PTSD to Negative Cognitions: A 17-Year Longitudinal Study Sharon Dekel, Tamar Peleg, and Zahava Solomon With the growing interest in the role of cognitions in PTSD, this prospective study examined the course and bi-directional relationship between post-trauma cogni- tions and symptoms of PTSD. A sample of Israeli combat veterans, including former prisoners of war, was assessed in 1991, and later followed up in 2003 and 2008. PTSD symptoms were measured at three time points. Cognitions concern- ing the self and the world were measured twice. Applying Autoregressive Cross- Lagged (ARCL) modeling strategy, initial PTSD symptoms predicted subsequent negative cognitions but not vice versa. In addition, repeated measures design re- vealed that individuals with chronic PTSD symptoms had relatively negative cog- nitions that further amplified with time. More specifically, increasingly negative cognitions were documented among ex-prisoners of war. The main findings sug- gest that negative cognitions are fueled by PTSD and that in chronic PTSD there is an amplification of pathogenic outcomes over time. Discussion of the findings is in the context of current cognitive models of PTSD. Posttraumatic stress disorder (PTSD) is the most prevailing psychiatric outcome following trauma (Breslau, 2009). It impairs daily functioning and overall well-being (Corry, Klick, & Fauerbach, 2010). While a sizeable portion of survivors experience dis- tress that fades within weeks, a significant sub-group fails to recover and suffers from enduring symptoms (e.g., Milliken, Auchter- lonie, & Hoge 2007; Shalev, 2009). Individ- uals exposed to a trauma of prolonged and extreme nature have a heightened vulnerabil- ity for PTSD (Kessler, 2000). In recent years, the role of cognitions in PTSD has gained increasing attention. Among the cognitions receiving empirical scrutiny are core cognitions concerning the self and the world held by survivors in the wake of trauma (e.g., Ehlers & Clark, 2000). While maladaptive (excessively negative)