The purpose of this study is to find out if a non-medication treatment can reduce nightmares in people with Rapid Eye Movement (REM) Sleep Behavior Disorder. Participants will be in the study for a total of 7 sessions, with some sessions including their romantic partners.

In this study, participants will receive the treatment through videoconference. They will complete two assessments during the study. Those with RBD will attend 7 sessions, while their partners will join them for 2 of these sessions. The study aims to see if this treatment can reduce the frequency and severity of nightmares.

• Who can participate: Adults aged 18 or older who have been diagnosed with RBD and live in the United States can participate. They must have a frequency of nightmares of at least 3 times per week and live with a romantic partner willing to join the study. Participants should have stable medication for at least a month before and during the study.
• Study details: Participants will engage in a series of videoconference sessions to receive a behavioral treatment aimed at reducing nightmares. They will also complete assessments to measure the effects of the treatment. Romantic partners will participate in some of these sessions to support the treatment process.
• Study visits: The study requires 7 visits.