Effects of trauma-focused rumination among trauma-exposed individuals with and without posttraumatic stress disorder: An experiment.

Rumination, or thinking repetitively about one's distress, is a risk factor for posttraumatic stress disorder (PTSD). Current theories suggest that rumination contributes to PTSD symptoms directly, by increasing negative reactions to trauma cues (i.e., symptom exacerbation), or represents a form of cognitive avoidance, if verbal ruminations are less distressing than trauma imagery. The goal of this study was to test the symptom exacerbation and cognitive avoidance accounts of trauma-focused rumination. We recruited 135 trauma-exposed participants (n = 60 diagnosed with PTSD) and randomly assigned them to ruminate about their trauma, distract themselves, or engage in trauma imagery. For individuals with and without PTSD, rumination led to larger increases in subjective distress (i.e., negative affect, fear, sadness, subjective arousal, valence) than distraction, η p 2 s = .04-.13, but there were no differences between rumination and imagery η p 2 s = .001-.02. We found no evidence that rumination or imagery elicited physiological arousal, ds = 0.01-0.19, but did find that distraction reduced general physiological arousal, as measured by heart rate, relative to baseline, d = 0.84, which may be due to increases in parasympathetic nervous system activity (i.e., respiratory sinus arrhythmia), d = 0.33. These findings offer no support for the avoidant function of rumination in PTSD. Instead, the findings were consistent with symptom exacerbation, indicating that rumination leads directly to emotional reactivity to trauma reminders and may be a fruitful target in PTSD intervention.