Imagery Rehearsal Therapy (or IRT) is a cognitive-behavioral treatment for reducing the frequency and intensity of nightmares among people with PTSD. IRT uses techniques that helps people with PTSD "rescript," or alter, the endings of their nightmares while they are awake. When you come up with an alternative, less distressing outcome, nightmares can become less upsetting and debilitating.
In IRT, you will be presented with information on sleep, nightmares, and what IRT entails. You will also learn how to monitor your nightmares. Your therapist will help you come up with detailed, alternative, non-distressing endings for nightmares that you've experienced. While awake, you can rehearse each nightmare with the altered ending.
IRT is a time-limited therapy, meaning that there is a defined duration of treatment. One reason for this is that IRT is focused specifically on nightmares and sleep difficulties. It doesn't really address other symptoms of PTSD. Therefore, if you are seeking out treatment for a variety of PTSD symptoms, you may want a more comprehensive treatment, such as exposure therapy.