A test of the diathesis-stress model in the emergency department: who develops PTSD after an acute coronary syndrome?

Most acute coronary syndrome (ACS) patients first present to the emergency department (ED). Patients who present to overcrowded EDs develop more posttraumatic stress disorder (PTSD) symptoms due to the ACS than do patients who present to less crowded EDs, but no research has indicated whether some patients may be more vulnerable to the effects of ED crowding than others. In an observational cohort study, we tested whether depressed patients developed more ACS-induced PTSD symptoms under conditions of ED overcrowding than patients who had never been depressed. We conducted psychiatric interviews for current and past depression in 189 ACS patients admitted through the ED within a week of hospitalization, and screened for PTSD symptoms 1 month later using the Impact of Events Scale-Revised. The sum of ED admissions for the 12 h prior to and 12 h after each participant's admission was categorized into tertiles for analysis. In a 3 (ED crowding tertile) by 3 (never, past, current depression) analysis of covariance adjusted for demographic and clinical factors, we found significant effects for ED crowding, depression status, and their interaction (all p's < .05). Mean PTSD scores were significantly higher (p = .005) for participants who were currently depressed and were treated during times of high ED crowding [25.38, 95% CI = 16.18-34.58], or had a history of depression [10.74, 95% CI = 6.86-14.62], relative to all other participants, who scored 5.6 or less. These results suggest that depressed ACS patients may be most vulnerable to the stress-inducing effects of ED crowding.