ABSTRACT
Post traumatic stress disorder (PTSD) is one of the few DSM-IV (American Psychiatric Association, 2000) diagnoses where, in addition to symptoms, an external cause of pathology (having witnessed or experienced a traumatic event) is a diagnostic criterion. Yet many individuals who experience similar events do not develop PTSD. The differences may be due to the different ways in which people cope with traumatic experiences. Like others (e.g. Herman et al., 1989; Herman, 1992; Hesse et al., 2003), we suggest that successfully resolving a trauma requires its integration into the survivor's previous and ongoing experiences. This chapter explains how this integration happens using a theory of psychological change that we call the assimilation model (Stiles et al., 1990; Stiles, 2002). The model describes a developmental process of coming to terms with problematic experiences, including traumas. Like other metacognitive models, it suggests that people get symptomatic and functional relief from PTSD as they develop more advanced ways to respond to their trauma, cognitively and socioemotionally and that psychotherapy can facilitate this development.
