top of page

Prolonged Exposure Therapy

 Reviewed by Psychology Today Staff

PET is a form of psychotherapy for post-traumatic stress disorder (PTSD). Originally developed by Edna Foa, Ph.D., PET is endorsed by both the American Psychiatric Association and the Department of Veterans Affairs and Defense. After a traumatic event, some people experience unwanted thoughts, disturbing nightmares, feelings of hopelessness, depression, and hypervigilance. If you have these symptoms, you understandably want to avoid thoughts, feelings, and things that remind you of the trauma. The goal of PET is to gradually help you reengage with life, especially with things you have been avoiding. By doing so, you will strengthen your ability to distinguish safety from danger and decrease your PTSD symptoms.

When It's Used

PET is appropriate for anyone who has experienced or witnessed a traumatic event. Many people who experience a traumatic event do not develop PTSD, and PET is not necessary for those without a PTSD diagnosis. Additionally, given that the completion of PET requires a person to speak about the trauma and to encounter trauma-related thoughts, feelings, and objects, you may experience moderate distress. This distress is often brief, and people typically feel significantly better because of treatment.

What to Expect

PET is conducted by a single clinician through one-on-one therapy. Sessions typically last 90 minutes and occur once a week for approximately three months, though treatment can be shorter at two months or longer at 15 weeks. PET treatment involves Imaginal Exposure and In Vivo Exposure.

During Imaginal Exposure sessions, you will discuss some of the events of your trauma. A therapist might ask you to write down your traumatic experience, read the experience aloud—in and out of session. Your therapist will guide you through the retelling of your trauma. You will explore your thoughts and feelings, which is called processing. This will help you decrease the unwanted traumatic reminders, as well as feel less distress when recalling the trauma. In Vivo Exposure, meaning “in life,” sessions involve your real-life interaction with safe things that you have been avoiding. In these sessions, your therapist will first ask you to make a list of the things you have been avoiding (sounds and places, for example). You will create an “exposure hierarchy” by ranking these avoided things based on how much distress they cause you when you encounter them.

How It Works

PET is based on associative learning theory, when two things appear together the brain learns to connect or associate them. Ivan Pavlov created the most famous associative learning experiment by repeatedly ringing a bell before presenting his dogs with food. The dogs began to salivate at the sound of the bell, as they learned to associate the bell with food. To break this association, Pavlov then repeatedly rang the bell without giving the dogs any food; the dogs eventually stopped salivating when they heard the bell. This same process is behind PTSD. When a trauma occurs, there are many things in the environment—smells, sights, sounds—that the brain associates with the trauma. When we encounter those things outside of the trauma, the brain expects danger, causing fear and anxiety.

bottom of page