The uniqueness of the DSM definition of post-traumatic stress disorder: implications for research

The official definition of post-traumatic stress disorder (PTSD) in DSM-III and is subsequent DSM editions is based on a conceptual model that brackets traumatic or catastrophic events from less severe stressors and links them with a specific syndrome. The diagnosis of PTSD requires an identifiable stressor and the content of the defining symptoms refers to the stressor, for example, re-experiencing the stressor and avoidance of stimuli that symbolize the stressor. Temporal ordering is also required: when sleep problems and other symptoms of hyperarousal are part of the clinical picture, they must not have been present before the stressor occurred. The ICD-10 definition of PTSD follows the same model. The defining symptoms alone, without a connection to the stressor, are not regarded as PTSD (Green et al . 1995). Since the introduction of PTSD in DSM-III, the official definition has been adopted in most studies, although discussions about the validity of the definition has continued (Breslau Davidson Green et al . 1995). Although it is widely believed that other disorders (e.g. major depression) can be precipitated by external events, these disorders can occur independent of stressors and do not require a link with a traumatic event in their diagnostic criteria. Previous classifications that separated major depression into stress-related (reactive) or endogenous have been abandoned in newer versions of the DSM, because of lack of evidence of the validity of this distinction.