Meta-analytic studies found exposure to be the most effective treatment in PTSD. Results are less clear with regard to acute stress disorder.

To evaluate the additional effect of exposure therapy to supportive counseling.

The assessment of subjective measures and the heart-rate (HR) response to trauma reminders in the two treatment conditions.

Forty recent trauma victims with acute stress disorder were randomly assigned to three sessions of either prolonged exposure (PE) or supportive counseling (SC) with both groups also receiving psychoeducation and progressive relaxation. PE was administered imaginal and in vivo, both being therapist-assisted. Assessments were carried out before and after treatment and again after three months. Patients were shown ideosyncratic trauma-related pictures and autonomic responses assessed. Four years later, patients were asked by telephone whether they had required further treatment.

There were no significant group differences with regard to symptomatic improvement at the end of treatment. Before treatment both groups showed HR acceleration to trauma-related pictures. After treatment the PE group showed attenuation of the HR-response and a reduction of spontaneous skin conductance fluctuations (SF) whereas the SC group showed a decelerative (orienting) HR response and an increase in SF. Over the next four years 43% of the SC group and and 9% of the PE group required further treatment.

The data show that SC, unlike PE, fails to attenuate autonomic responses to trauma-related stimuli suggesting that the former treatment fails to reorganize the trauma network.