Insomnia is a major public health problem considering its high prevalence, impact on daily life, co-morbidity with other disorders and societal costs. Cognitive behavioral treatment for insomnia (CBTI) is currently considered to be the preferred treatment. However, no meta-analysis exists of all studies using at least one component of CBTI for insomnia, which also uses modern techniques to pool data and to analyze subgroups of patients. We included 87 randomized controlled trials, comparing 118 treatments (3724 patients) to non-treated controls (2579 patients). Overall, the interventions had significant effects on: insomnia severity index (g = 0.98), sleep efficiency (g = 0.71), Pittsburgh sleep quality index (g = 0.65), wake after sleep onset (g = 0.63) and sleep onset latency (SOL; g = 0.57), number of awakenings (g = 0.29) and sleep quality (g = 0.40). The smallest effect was on total sleep time (g = 0.16). Face-to-face treatments of at least four sessions seem to be more effective than self-help interventions or face-to-face interventions with fewer sessions. Otherwise the results seem to be quite robust (similar for patients with or without comorbid disease, younger or older patients, using or not using sleep medication). We conclude that CBTI, either its components or the full package, is effective in the treatment of insomnia.

This study examined the effectiveness and feasibility of therapist-guided Internet-delivered exposure (EX) and behavioral activation (BA) for complicated grief and rumination. Forty-seven bereaved individuals with elevated levels of complicated grief and grief rumination were randomly assigned to three conditions: EX (N=18), BA (N=17), or a waiting-list (N=12). Treatment groups received 6 homework assignments over 6 to 8weeks. Intention-to-treat analyses showed that EX reduced complicated grief, posttraumatic stress, depression, grief rumination, and brooding levels relative to the control group at posttreatment (d=0.7-1.2). BA lowered complicated grief, posttraumatic stress, and grief rumination levels at posttreatment (d=0.8-0.9). At 3-month follow-up, effects of EX were maintained on complicated grief and grief rumination (d=0.6-1.2), and for BA on complicated grief, posttraumatic stress, and grief rumination (d=0.8-0.9). EX reduced depression more strongly than BA (d=0.6). Completers analyses corroborated results for EX, and partially those for BA, but no group differences were detected. BA suffered from high dropout (59%), relative to EX (33%) and the waiting-list (17%). Feasibility appeared higher for EX than BA. Results supported potential applicability of online exposure but not behavioral activation to decrease complicated grief and rumination.

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.

Our findings indicate that ImRs is a promising intervention for psychological complaints related to aversive memories, with large effects obtained in a small number of session.

A commentary on this article appears in this issue on page 13.