Systematic review: REM sleep, dysphoric dreams and nightmares as transdiagnostic features of psychiatric disorders with emotion dysregulation - Clinical implications

Fragmented rapid eye movement (REM) sleep disrupts the overnight resolution of emotional distress, a process crucial for emotion regulation. Emotion dysregulation, which is common across psychiatric disorders, is often associated with sleep disturbances. This systematic review explores how REM sleep and nightmares affect emotion processing and regulation in individuals with psychiatric disorders where emotion dysregulation is a key concern, suggesting novel sleep-related treatment pathways. We performed a PRISMA-compliant systematic search of the PUBMED, Web of Science, and EBSCO databases from January 1994-February 2023. This systematic review targeted studies on REM sleep, nightmares, and emotion regulation in a postpubescent clinical population with affective dysregulation. The quality of the studies was assessed via the Newcastle‒Ottawa Scale (NOS), adapted for cross-sectional studies. From the 714 screened records, 28 articles met the inclusion criteria and focused on REM sleep, dreams, or nightmares in individuals with mood disorders (k = 8), anxiety disorders (k = 1), posttraumatic stress disorder (PTSD) (k = 16), non-suicidal self-injury (NSSI), personality disorders (k = 2), and autism (k = 1). Fifteen studies used objective sleep measures, seventeen used self-reported assessments, six included treatment components, eight investigated nightmares, and three examined dreams. NOS scores ranged from moderate to high. REM sleep disturbances represent a transdiagnostic feature across psychiatric disorders and are crucial for emotion regulation. Nightmares are associated with suicidal behaviour and emotion dysregulation. Targeted sleep interventions may improve emotion regulation and mental health outcomes. Future research should explore the role of REM sleep in disorder prognosis to develop tailored interventions.