population predominated, the participants were mostly male, and when the majority of cases had been sexually abused or assaulted, participants were mostly female although there are instances when that is not the case. With mixed trauma type, the sex ratios were more equally divided.


The committee found a substantial number of randomized controlled trials (RCTs) comparing exposure therapies (alone or with some other component) to wait-list or usual care controls. The category of exposure comprised exposure therapies alone and several different combinations of exposure with cognitive restructuring or coping skills training. The large number of studies of exposure therapy comprises the range of features found in the rest of the psychotherapy studies, with regard to length of treatment, variety of trauma, age of participants, training of clinicians, and so on.

Participants in the exposure therapy studies had suffered a variety of traumas, including combat-related, sexual abuse and/or assault, civil war, and motor vehicle accident. The mean age of study participants ranged from early-20s to the 50s, with most studies reporting a mean age between the mid-30s and mid-40s. Few studies reported duration of illness, but many provided information about the time since trauma, which ranged from several months in studies with rape survivors to more than two decades in studies with veterans. Some studies, such as those in survivors of sexual assault, included only female participants, while many others had a mix of men and women, and studies in people traumatized by combat had all male participants. Some, but not all, studies provided information about the race/ethnicity of participants. In most studies, participants were white, with a smaller number of studies reporting percentages of non-white participants at approximately 20 percent, 30 percent, and in a few cases, nearly 50 percent.

Exposure therapy included psychoeducation, breathing retraining, and relaxation, in addition to exposure (specifically imaginal and in vivo exposure, flooding, directed therapeutic exposure, etc.). Some exposure therapy programs also required completing homework, generally repeated exposure to a trauma tape or other record of the trauma narrative. Exposure studies, like other psychotherapy studies, are lengthy and require considerable investment of time, emotion, and effort. Most studies administered exposure and usually also the comparison treatments for at least several weeks (e.g., 4.5, 9–12, 30 weeks). Only a small number of studies provided treatment in one session or for a short time: one 60-minute session in Basoglu et al. (2005), one session in Basoglu et al. (2007), two 90-minute sessions in Boudewyns et al. (1993).

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