Longitudinal study of acute stress disorder, posttraumatic stress disorder and dissociation following myocardial infarction.

Since dissociation has been recognized as a marker of posttraumatic processes, this study examines the chronological relations between dissociation and stress reactions (acute stress disorder, ASD, and posttraumatic stress disorder, PTSD) following myocardial infarction (MI). One hundred sixteen MI patients were examined twice: within 1 week of the trauma (time 1) and 7 months later (time 2). Sixty-seven matched controls were studied in a parallel interval. ASD was assessed at time 1, PTSD at time 2, and dissociative tendencies at both times. ASD and PTSD were moderately associated with levels of dissociation. In addition, while the MI patients did not differ from the controls in level of dissociation, both in time 1 and time 2, among the MI group, PTSD was associated with an increase in dissociation. These findings may reflect either the development of two comorbid entities, or a presentation of a dissociative subtype of PTSD.