Assessing the Severity of Posttraumatic Stress Disorder: Relation Between Dichotomous and Continuous Measures

Both the Diagnostic and Statistical Manual of Mental Disorders (DSM-III; American Psychiatric Association, 1980) and the Impact of Event Scale (IES) assess distress following trauma. This article assesses the interrelation between these two instruments for soldiers who suffered from combat stress reactions (N = 382) and for a matched control group (N = 334). Results indicated that subjects suffering from posttraumatic stress disorder (PTSD) according to the DSM-III yielded higher scores on the Intrusion and Avoidance factors of the IES. Furthermore, the Intrusion factor was predominantly associated with each of the criteria of the DSM-III diagnosis. Although the IES and the DSM-III overlap, they may tap different aspects of battle-related PTSD.