Combined treatment of nightmares with targeted memory reactivation and imagery rehearsal therapy: a randomized controlled trial

Background: Nightmare disorder (ND) is characterized by dreams with strong negative emotions occurring during rapid-eye movement (REM) sleep. ND is mainly treated by imagery rehearsal therapy (IRT), where the patients are asked to change the negative story line of their nightmare to a more positive one.

Methods: We used targeted memory reactivation (TMR) during REM sleep to strengthen IRT-related memories and accelerate remission of ND. Thirty-six patients (27 women) with ND were asked to perform an initial IRT session and, while they generated a positive outcome of their recurrent nightmare, half of the patients were exposed to a sound (TMR group), while no such pairing with a sound took place for the other half (control group). During the next two weeks, all patients performed IRT every evening at home, and were exposed to the sound during REM sleep with a wireless headband, which automatically detected sleep stages. The frequency of nightmares per week at 2 weeks and at a three-month follow-up was used as primary outcome measure.

Results: We found that the patients of the TMR group had less frequent nightmares (p=.026, Cohen's d=1.05) and more positive dream emotions (p=.004, Cohen's d=1.06) than patients of the control group after two weeks of IRT, and a sustained decrease of nightmares after 3 months (p=.006, Cohen's d=1.45).

Conclusions: By demonstrating the effectiveness of TMR during sleep to potentiate therapy, these results have clinical implications for the management of ND, with plausible relevance for learning-based therapies in other psychiatric diseases. Additionally, these findings show that TMR applied during REM sleep can modulate emotions in dreams.