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Prolonged Exposure Therapy

Ages 15-70

Rating: Level 1


Prolonged Exposure (PE) Therapy is a cognitive-behavioral treatment program for individuals suffering from posttraumatic stress disorder (PTSD). The program consists of a course of individual therapy designed to help clients process traumatic events and thus reduce trauma-induced psychological disturbances. Twenty years of research has shown that PE Therapy significantly reduces the symptoms of PTSD, depression, anger, and general anxiety. PE Therapy has three components:

  • Psychoeducation about common reactions to trauma and the cause of chronic posttrauma difficulties
  • Imaginal exposure—repeated recounting of the traumatic memory (emotional reliving)
  • In-vivo exposure—gradually approaching trauma reminders (e.g., situations, objects) that, despite posing no harm, are feared and avoided

PE Therapy reduces PTSD symptoms such as intrusive thoughts, intense emotional distress, nightmares and flashbacks, avoidance, emotional numbing and loss of interest, sleep disturbance, concentration impairment, irritability and anger, hypervigilance, and excessive startle response.

It can be used in a variety of clinical settings, including community mental health outpatient clinics, veterans’ centers, rape counseling centers, private practice offices, and inpatient units. Treatment is individual and conducted by therapists trained to use the PE Manual, which specifies the agenda and treatment procedures for each session. Standard treatment consists of 9 to12 once- or twice-weekly sessions, each lasting 90 minutes:

  • Sessions 1 and 2 are for information gathering, presentation of the treatment rationale, construction of a list of avoided situations for in-vivo exposure, and initiation of in-vivo homework. Clients are taught to reduce anxiety by slow, paced breathing.
  • Sessions 3 to 8 (or 11) are homework review, imaginal exposure (i.e., prolonged [40 to 60 minutes] of repeated recounting of traumatic memories), processing of imaginal exposure experience, reviewing in-vivo exposure, and homework assignments.
  • The final session consists of imaginal exposure, review of progress and skills learned, and discussion of the client’s plans for maintaining gains.

The treatment course can be shortened or lengthened depending on the client’ needs and the rate of progress.


The effectiveness of PE Therapy has been established through single-case reports, quasi-experimental designs, and, above all, many randomized control studies. It is by far the most studied treatment program for PTSD and has broad empirical support from studies of clients with PTSD resulting from various types of traumas. Further, PE Therapy is considered by expert consensus the treatment of choice for PTSD clients whose prominent symptoms include intrusive thoughts, flashbacks, and trauma-related fear and avoidance.

The first report on the application of prolonged exposure therapy to PTSD rape victims appeared in 1991 with a controlled study. Rape victims with PTSD were randomly assigned to one of four conditions: stress inoculation training (SIT), prolonged exposure (again, PE), supportive counseling (SC), or waitlist control (WL). SIT is a treatment package of anxiety management techniques developed for victims who remained highly fearful 3 months after being raped. SC used a problem-solving approach for daily problems. Treatments were delivered in nine biweekly 90-minute individual sessions. Measures of PTSD symptoms, rape-related distress, general anxiety, and depression were administered at pretreatment, posttreatment, and follow-up (M=3.5 months posttreatment).

A second controlled study compared PE, SIT, the combination of SIT and PE, and WL on clients with PTSD postsexual and nonsexual assault. In this study, 96 female victims of assault were randomly assigned to one of the four conditions. Treatments consisted of nine, twice-weekly 90-minute sessions. Sixty-nine participants were victims of sexual assault, and 27 were victims of nonsexual assault. All victims were at least 16 at the time of the assault. Sixty-three percent were white, with the rest African-American. Measures of PTSD symptoms, rape-related distress, general anxiety, and depression were administered at pretreatment, posttreatment, and 3, 6, and 12 months later. Interview measures included the SCID, PSDS–I, and the Social Adjustment Scale. Self-report measures included the Beck Depression Inventory and the State-Trait Anxiety Inventory.


In the first study, all three active treatments showed significant improvement in PTSD symptoms and depressive symptoms at posttest, while the waitlist did not improve. These treatment effects were maintained at 6-month follow-up. On most outcome measures, PE was more effective than the other two treatments, although this difference did not always reach significance.

In the second study, all conditions produced improvement on all measures (measures of PTSD, anxiety, and depression) immediately posttreatment and at follow-up. SIT produced significantly more improvement on PTSD symptoms than the waitlist group following treatment. At follow-up, PE produced superior outcomes on PTSD symptoms. Clients who received PE continued to improve after treatment termination, whereas clients in the SIT and SC conditions evidenced no change between posttreatment and follow-up.

Risk Factors


  • Life stressors
  • Mental disorder/Mental health problem/Conduct disorder
  • Victimization and exposure to violence


  • Pattern of high family conflict


  • Peer rejection

Protective Factors


  • Self-efficacy
  • Social competencies and problem-solving skills


  • Effective parenting
  • Good relationships with parents / Bonding or attachment to family


  • Good relationships with peers
  • Involvement with positive peer group activities


  • SAMHSA: Model Programs


Foa, Edna B., Constance V. Dancu, Elizabeth A. Hembree, Lisa H. Jaycox, Elizabeth A. Meadows, and Gordon P. Street. 1999. “A Comparison of Exposure Therapy, Stress Inoculation Training, and Their Combination for Reducing Posttraumatic Stress Disorder in Female Assault Victims.” Journal of Consulting and Clinical Psychology 67(2):194–200.

Foe, Edna B., Barbara Olasov Rothbaum, David S. Riggs, and T. Murdock. 1991. “Treatment of Posttraumatic Stress Disorder in Rape Victims: A Comparison Between Cognitive-Behavioral Procedures and Counseling.” Journal of Consulting and Clinical Psychology 59:715–23.


Edna B. Foa, Ph.D.
Director, Center for the Treatment and Study of Anxiety, Department of Psychiatry
3535 Market Street, Suite 600 North
University of Pennsylvania
Philadelphia, PA 19104
Phone: (215) 746-3327
Fax: (215) 746-3311
Web site:

Technical Assistance Provider

Elizabeth A. Hembree, Ph.D., or David S. Riggs, Ph.D.
Center for the Treatment and Study of Anxiety, Department of Psychiatry
University of Pennsylvania
3535 Market Street, 600 North
Philadelphia, PA 19104
Phone: (215) 746-3327
Fax: (215) 746-3311
Web site: