This consensus paper provides an overview of the state of the art in research on the aetiology and treatment of nightmare disorder and outlines further perspectives on these issues. It presents a definition of nightmares and nightmare disorder followed by epidemiological findings, and then explains existing models of nightmare aetiology in traumatized and non‐traumatized individuals. Chronic nightmares develop through the interaction of elevated hyperarousal and impaired fear extinction. This interplay is assumed to be facilitated by trait affect distress elicited by traumatic experiences, early childhood adversity and trait susceptibility, as well as by elevated thought suppression and potentially sleep‐disordered breathing. Accordingly, different treatment options for nightmares focus on their meaning, on the chronic repetition of the nightmare or on maladaptive beliefs. Clinically, knowledge of healthcare providers about nightmare disorder and the delivery of evidence‐based interventions in the healthcare system is discussed. Based on these findings, we highlight some future perspectives and potential further developments of nightmare treatments and research into nightmare aetiology.

Sleep disturbances are often referred to as the hallmark of Post-Traumatic Stress Disorder (PTSD). Although PTSD is prevalent in refugees, studies on sleep disturbances in trauma-affected refugees are scarce. This article presents the results of two studies: a systematic review of the literature on treatment of sleep disturbances in adult trauma-affected refugees and a study of the role of sleep disturbances in the PTSD symptom structure. Study 1, the literature review, identified five studies on treatment of sleep disturbances: four studies were on pharmacological treatment and one study on music therapy. The identified studies had small sample sizes and few carried out statistical analysis. It was not possible from the available literature to recommend any specific treatment of sleep disturbances. In Study 2, a clinical sample of 752 refugees, fulfilling criteria for PTSD and enrolled in treatment at the Competence Centre for Transcultural Psychiatry, Denmark, completed the Harvard Trauma Questionnaire (HTQ) before and after treatment. To determine item discrimination, the data was tested with a Rasch model. 99.1% reported trouble sleeping and 98.7% reported recurrent nightmares. The Rasch analysis displayed fit residuals of 0.05 for trouble sleeping and -1.16 for nightmares, indicating sufficient discrimination. Trouble sleeping and nightmares proved important parts of the HTQ response structure. This study indicates that sleep disturbances are a prominent part of the PTSD symptom structure in refugees but that research on treatment of sleep disturbances is limited. Further research on sleep disturbances in trauma-affected refugees is therefore needed.

Sleep disturbances are frequently part of the symptomatology in refugees with post‐traumatic stress disorder (PTSD). It has been suggested that targeting sleep disturbances may enhance the outcome of PTSD treatment. However, randomized studies on the effect of treatment focusing on sleep disturbances in refugees with PTSD are lacking. The aim of this study was to examine add‐on treatment with imagery rehearsal therapy (IRT) and/or mianserin against treatment as usual (TAU) alone in a sample of trauma‐affected refugees with PTSD at 8–12 months follow‐up. In a randomized controlled trial, 219 adult refugees diagnosed with PTSD and suffering from sleep disturbances were randomized to four groups (1:1:1:1) receiving, respectively, TAU, TAU + mianserin, TAU + IRT, and TAU + IRT + mianserin. The primary outcome was subjective sleep quality (Pittsburgh Sleep Quality Index) and the secondary outcomes included PTSD and depression symptoms, level of functioning and subjective well‐being. The data were analysed using mixed models. The only significant effect of IRT was on level of functioning (p = .040, ES 0.44), whereas there was no significant effect of mianserin on any of the measured outcomes. Low adherence to both IRT (39%) and mianserin (20%) was observed. Contrary to our hypothesis, we did not find IRT or mianserin to be superior to TAU. The low adherence may potentially cause an underestimation of the effect of IRT and mianserin and indicates a necessity to further analyse the complex factors that may impact the motivation and ability of trauma‐affected refugees to participate in and profit from available treatment options.