Edna Foa on Prolonged Exposure Therapy

Edna Foa: Exposure therapy is used mostly with anxiety disorder. The idea is that people who suffer from anxiety disorders—who get anxious when they confront safe situations or objects—are taught through exposure therapy to become less afraid, or not afraid at all, of the things they’re fearful of. So if the fear is a normal fear—like the fear of driving on the track when you see the train whipping by very fast—you don’t want to teach people to get over it. You don’t want to change people’s fear of driving over the track just in front of the train, because normal fears protect people from doing things that will harm them. The idea behind exposure therapy is that the therapist helps patients to confront or approach what they’re afraid of, because the things they’re afraid of are intrinsically not dangerous. Through exposure to these situations, they learn that there is no reason to be afraid of these situations. The disaster they expected does not occur. Originally, exposure therapy was derived from animal studies. In these experiments, scientists condition a mouse to become afraid of a red light by pairing the light with electrical shock. And after a certain numbers of pairings, the mouse will start showing fear responses when the red light is presented, even when it’s not paired anymore with shock. We call this response a conditioned fear. Then if we want to eliminate the mouse’s fear of red light, we present it with a red light without the shock. After repeated presentation of the light without shock, the animal stops showing the fear reaction to the light. That’s called extinction. In the ’60s and the ’70s, several experts, in England and the United States, translated the animal results to human beings and said, "Let’s suppose that the anxiety disorders—such as claustrophobia or fear of heights—are like a response that was conditioned. The person was conditioned to be afraid of elevators even though being in an elevator is not dangerous. So how do we eliminate the fear of elevators? We instruct the person to ride on an elevator many times until the fear is extinguished."

EF: Well, it’s called flooding if the therapist conducts the exposure very abruptly. And it’s called systematic desensitization if the therapist is doing the exposure very slowly in small increments, and if he pairs the exposure with relaxation. There were big debates in the '60s and the '70s about what works better, and whether flooding is dangerous. Some experts, like Wolpe, thought it was dangerous to do flooding because the person will actually become more rather than less fearful.

EF: No, not really. According to some theories, flooding should make the patient feel worse. But according to other theories, abrupt exposure should extinguish the patient’s fear more quickly, so it is actually more efficient.

EF: Well, it depends. Not necessarily. Let’s say that somebody is afraid of going to the supermarket. People with panic disorder, you know, are afraid of going to places where they cannot escape quickly, like sitting in the first row at the movies. It takes longer to get out from the first row than from last row. Experts did abrupt exposure, getting patients to sit in the front seat from the start of the therapy, and other experts said, "Let’s do it incrementally—let them sit in the last row first, and then in the row before the last, and then two rows before the last, and then five rows before the last."

EF: Exactly. Gradual exposure gets patients used to each one of those stages, and eventually the patient will sit in the first row. Now, studies have found that doing abrupt exposure is as effective as doing gradual exposure, except that the patients in the gradual exposure suffer less. But flooding doesn’t really make them worse, as Wolpe thought. So we know now that we can do flooding, or we can do systematic desensitization. Both work. Today, experts don’t quarrel about this issue anymore; all therapists use more or less a gradual exposure, but not as gradual as systematic desensitization, because that takes too long and is unnecessary.So that’s what exposure is. Now, how does exposure work? It works because of a mechanism that we call extinction. Extinction is not unlearning what you learned, but rather it’s learning something new—it’s learning that what you were afraid of is not dangerous. Some experts say that the mechanism is the reduction of the anxiety—that gradually you’re less and less fearful. This is called habituation. But habituation is not an explanation for why patients get less fearful with exposure therapy.My theory is that exposure reduces fear and anxiety because the patient learns that the bad thing he thought would happen to him does not happen. Therefore, it’s very important to plan in a way which will ensure that the thing the patient is afraid of will not happen during the exposure. Let’s say after being raped a woman starts to be afraid of going anywhere by herself after dark. The therapist then plans exposures to places that are not safe after dark, and she is attacked again. That’s not a good exposure, because it doesn’t teach the patient that what she was afraid of does not happen.I always give the example of a person that is afraid of big dogs, but not of small dogs. The therapist decides to treat him by exposure to dogs, and brings to the session a small dog. Well, because the patient is not afraid of small dogs, this exposure will not work. Exposure needs to include the things that the patient is afraid of. The therapist then brings a big dog to the therapy session to do exposure. The patient enters the room, sees the dog, and gets very fearful. With the encouragement of the therapist, the patient slowly approaches the dog, which the therapist holds on a leash. When the patient gets close to the dog, the dog jumps on him and bites him. This is again not a successful exposure, because what does the person learn from it? He learns that he was right all along, that big dogs are dangerous.

EF: Exactly, it reinforces rather than extinguishes the fear. So that’s the way exposure works. In order to implement therapeutic exposure, the therapist has to find out what the person is afraid of, then make a list of these things and organize this list from the not-so-fearful situation to most fearful situation, in a kind of hierarchy. In order to create a good hierarchy, the therapist teaches the patient to assign a number, on a zero-to-one-hundred scale, to each situation. This number signifies how much fear the patient would have if he would be confronted with this situation. It is important that the therapist makes sure that the situations on the list are not really dangerous.The therapist chooses a situation by saying to the patient, "Let’s choose a situation that is about forty on the scale. Which of these situations do you think you are able to do for homework next week or in the session with me?" The patient selects a situation and begins to practice approaching it, staying in the situation until he feels that the anxiety goes down and realizes that the fear is not realistic.So exposure works through two mechanisms. The first is that the situation elicits the patient’s fear—there is a match between the situation that the therapist is presenting to the patient and the patient’s own internal fear. The second mechanism is that the exposure situation contains information that is incompatible with the information that the patient has in his mind. In the example I gave you about the dog-phobic, if the patient is afraid that large dogs will bite him and the therapist presents him with a large dog that, over several instances, does not bite, the patient will cease to be afraid of big dogs. Patients don’t really need to be in the situation a long time—they don’t need to wait until the anxiety dissipates completely. They just need to be in the situation long enough to realize that what they feared would happen does not happen.