This Month’s Expert: Edna Foa, Ph.D., On Therapy for PTSD

This Month’s Expert: Edna Foa, Ph.D., On Therapy for PTSDTCR: Dr. Foa, how common is PTSD?

Dr. Foa: The epidemiological studies tell us that 60% of men in the United States and over 50% of women have been traumatized at least once in their lifetime.

TCR: That’s a surprisingly high figure. What type of trauma are we talking about?

Dr. Foa: The DSM-IV definition of a trauma, which is either being a victim of or witnessing an event that involves a threat or perceived threat of injury or death to oneself or to another person, where the traumatized person was terrified and felt helpless during the event. This includes, for example, people who have been in traffic accidents in which they have seen horrifying things, and people in the inner city in America who have seen people shot. Yet the rate of actual PTSD is much lower than the rate of trauma. Most people are resilient.

TCR: What types of trauma are most likely to lead to PTSD?

Dr. Foa: Rape and combat. The prevalence of rape is about 3% of the population, but of people who were raped, 60% have had PTSD at some point in their life and 18% currently have PTSD. On the other side of the spectrum, natural disasters and traffic accidents have very low rates of PTSD. Overall, the rate of PTSD in the population in general is about 8% lifetime, with women having double the prevalence of men.

TCR: What do you suggest we ask in order to screen for PTSD?

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Dr. Foa: Ask, “Have you experienced a traumatic event?” in order to establish that a trauma happened. Then ask, “Do you have nightmares? Do you have intrusive thoughts about the traumatic event? Do you avoid things that you used to do before the trauma? Do you feel agitated, very anxious, on guard much of the time?” If a person gives positive answers to those four questions he or she is likely to suffer from PTSD.

TCR: Once we diagnose somebody, how do we decide about medications vs. therapy?

Dr. Foa: Availability is a factor. Medications are widely available, and the two FDA approved medications for PTSD, paroxetine and sertraline, yield about a 50% response rate. But in one small study we did, there was a 30% relapse rate when people stopped sertraline but those who received cognitive behavioral therapy (CBT) did not relapse.

TCR: So the bottomline is that CBT results in less relapse?

Dr. Foa: Yes, and many PTSD sufferers prefer therapy. A recent study done by two of my colleagues, Norah Feeney and Lori Zoellner, found that 75% of patients preferred psychotherapy to medication.

TCR: You’ve developed one of the most effective forms of PTSD treatment, “prolonged exposure (PE).” What is it, and how does it work?

Dr. Foa: Prolonged exposure involves two types of exposures: imaginal and in vivo exposure. In imaginal exposure, we ask patients to close their eyes and recount the traumatic event aloud as if it is happening now, including details of what is happening, their thoughts, and their feelings. And then we tape the narrative and the patient takes the tape home. When patients listen to their stories, many things happen. They change their perspective on the trauma. They might have blamed themselves for some parts of the trauma and now they realize that there is no reason to do this. Also, their memories stop eliciting anxiety, because remembering a traumatic event is not dangerous; it is only dangerous if you feel as if it is happening now. But once they separate from the memory, they can put it into the past; they gain control over the traumatic memory and lose the reexperiencing symptoms.

TCR: And what is “in vivo exposure”?

Dr. Foa: This begins by creating a hierarchy of situations that the patient avoids because of the trauma and then instructing him or her to confront these situations, beginning with the easiest and proceeding to the more difficult ones. For example, many patients with PTSD avoid crowded places, some avoid darkness, including going to movies. They avoid turning on the television because they may hear about an assault or something that would remind them of the trauma. So their life gets restricted. In vivo exposure allows them to go back to where they were before the trauma, gradually reclaiming their lives.

TCR: And why is it called “prolonged” exposure?

Dr. Foa: The “prolonged” refers to the fact that you want the patient to recount the trauma for about 30 to 45 minutes during the sessions and to stay in the avoided situations until the anxiety subsides.

TCR: How effective is prolonged exposure?

Dr. Foa: Multiple studies have shown that about 80% of patients participating in 9 to 12 sessions improve significantly, and about 40% actually lose their symptoms completely. And the method has been validated with a wide range of patients, including rape victims, people who were sexually abused as children, and victims of accidents, of torture, and of industrial disasters.

TCR: So is prolonged exposure considered the treatment of choice for PTSD these days?

Dr. Foa: Yes.

TCR: Do many people know how to do it?

Dr. Foa: Well, more and more. The main training program in the US is at the University of Pennsylvania. But there are many other places where it is taught, including Australia, Japan, Israel, and throughout Europe. We conducted a study in which we trained counselors from Women Organized Against Rape in Philadelphia in five days and after that we supervised them, once a week, and we found that they obtained results that are as good as ours.

TCR:There are relatively few psychiatrists who are going to want to invest the time in the full training. But do you think psychiatrists can do a limited version of prolonged exposure therapy?

Dr. Foa: With mild PTSD, yes. Encourage people to talk about the traumatic event with significant others and encourage them to gradually go to places that are fearful to them. For patients who come back and say, “Well I couldn’t do it,” refer them to a CBT expert.

TCR: Would you encourage psychiatrists to do the imaginal exposure with patients, or do they risk opening a Pandora’s box?

Dr. Foa: Contrary to clinical lore, that’s rarely a problem. PTSD patients are very protective of themselves. They are “experts in avoidance,” so the more common problem is that they tell the story without emotions and then they don’t get the benefit of prolonged exposure. The trick is to know how to help the patient get engaged in the traumatic memory.

TCR: Rather than having to worry about having to piece them together again.

Dr. Foa: Exactly. In fact, we have analyzed our data to see how many of our patients got worse, because some people said, “Oh, exposure therapy is dangerous.” We analyzed our own data from two studies and we found that not a single person got worse after exposure therapy, while 95% got significantly better. So there is no danger, just a question of how effective you are going to be if you are not tuned into the subtleties of the approach.

TCR: My impression is that your typical cognitive therapist does not use exposure therapy with PTSD patients.

Dr. Foa: Well some do and some don’t. Now, cognitive therapy alone, just talking to the patient about the trauma and about negative cognitions, is moderately effective, but if you add exposure to the cognitive therapy–even light exposure, like writing the story many times–it improves the outcome.

TCR: Have any of these therapies been compared in head-to-head studies with medications?

Dr. Foa: No. In fact, PTSD is the only anxiety disorder in which we don’t have a head-to-head comparison of CBT with medication. The study that comes closest is one that we did recently, funded by Pfizer, in which we found that adding CBT to Zoloft treatment improved outcome over Zoloft alone for partial responders to the medication, but this was an augmentation study rather than a head-to-head comparison.

TCR: But given your overall experience in research and your reading of the literature, what is your opinion about the relative efficacy of medications vs. therapy?

Dr. Foa: If you look specifically at prolonged exposure, it appears to do better than medication, though this is not necessarily the case with other types of cognitive behavioral therapy. This is especially true if you look at remission rates, in which PE appears to produce significantly more remissions than medication treatment.

This Month’s Expert: Edna Foa, Ph.D., On Therapy for PTSD

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This article was published in print 4/2004 in Volume:Issue 2:4.


APA Reference
Foa,, E. (2013). This Month’s Expert: Edna Foa, Ph.D., On Therapy for PTSD. Psych Central. Retrieved on April 3, 2020, from


Scientifically Reviewed
Last updated: 28 Jul 2013
Last reviewed: By John M. Grohol, Psy.D. on 28 Jul 2013
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