Post-traumatic stress disorder (PTSD) is frequently accompanied by additional sleep disturbances, such as nightmares and insomnia. Recent findings suggest a potential association between PTSD and REM sleep behavior disorder (RBD). This systematic review evaluates the current evidence on the PTSD–RBD relationship, with attention to prevalence, diagnostic approaches, shared pathophysiological mechanisms, and clinical implications.

A comprehensive search of PubMed, Web of Science, EMBASE, and PsycINFO was conducted up to July 2025. Eligible studies included observational, cohort, and experimental designs assessing RBD in individuals with PTSD. Methodological quality was appraised using the Newcastle–Ottawa Scale.

Seven studies, encompassing 4152 participants, met the inclusion criteria. Overall, PTSD was linked to a higher prevalence of probable or confirmed RBD, particularly among veterans. Adding to this, patients with isolated RBD appeared more likely to report comorbid PTSD than those diagnosed with other parasomnias. Evidence also indicated that PTSD-related RBD may be associated with more severe psychopathology, including heightened depressive symptoms, recurrent nightmares, and emotional dysregulation.

From a clinical standpoint, it is advisable to evaluate PTSD patients presenting with parasomnia symptoms for possible RBD, and to investigate PTSD history in those exhibiting dream enactment behaviors.