The mechanisms of action underlying the efficacy of psychological nightmare treatments: A systematic review and thematic analysis of discussed hypotheses

Short-term stability and night-to-night variability of sleep parameters in nightmares comorbid with chronic insomnia Disorder across multiple nights of polysomnography

STUDY OBJECTIVES

The purpose of this study was to examine the degree of short-term stability of polysomnographic (PSG) measured sleep parameters and the overall differences between individuals with comorbid nightmares and insomnia compared to those with chronic insomnia disorder alone or good sleeping controls across four nights in the sleep lab.

METHODS

A total of 142 good sleeping controls, 126 chronic insomnia alone, and 24 comorbid insomnia/nightmare participants underwent four consecutive nights of 8-hour PSG recordings. Outcomes included sleep continuity, architecture, and REM-related parameters across nights one through four. Intraclass correlation coefficients with mixed-effect variances and repeated-measure analysis of covariance were used, respectively, to determine short-term stability as well as between-participants and time-by-group interaction effects.

RESULTS

Wake after sleep onset and stage 1 showed "poor stability" in the comorbid insomnia/nightmare group compared to "moderate stability" in the good sleeping controls and chronic insomnia alone group. Significant between-group effects (all ps < .05) showed that the comorbid insomnia/nightmare group took longer to fall asleep and had a greater first-night-effect in stage 1 compared to good sleeping controls and chronic insomnia alone group; in addition, the comorbid insomnia/nightmare and insomnia alone groups slept shorter, with fewer awakenings and REM periods, compared to the good sleeping controls.

CONCLUSIONS

Nightmares are associated with abnormal sleep above and beyond REM disruption, as sleep continuity was the primary aspect in which poor stability and group differences emerged. The greater inability to fall asleep and instability of sleep fragmentation in those with comorbid insomnia/nightmares compared to chronic insomnia alone may be attributed to the impact of presleep anticipatory anxiety and nightmare-related distress itself.

CLINICAL TRIAL INFORMATION

The data analyzed in this study does not come from any current or previous clinical trials. Therefore, there is no clinical trial information to report.

A Retrospective Pilot Study of Imagery Rehearsal Therapy Enhanced with Narrative Therapy Principles for the Treatment of Nightmares in US Military Veterans

Introduction  Chronic nightmares are a common and disabling feature of posttraumatic stress disorder (PTSD) for which broadly effective treatments are still lacking. While imagery rehearsal therapy (IRT) demonstrates benefits for patients with idiopathic nightmares and some patients with PTSD-related nightmares, research indicates it may be less beneficial for veterans. Narrative therapy (NT) is a form of psychotherapy which is client-centered and value-focused and has demonstrated benefits for PTSD patients. The application of NT principles to IRT may provide a valuable therapeutic approach for treatment in veterans. Objective  To perform a retrospective chart review of veteran clients participating in a novel, brief intervention developed by the first author consisting of IRT enhanced with NT principles (N-IRT) for the treatment of nightmares. The primary outcomes were nightmare frequency and intensity, and the secondary outcome was the impact of the intervention on nightmare distress and coping, subjective sleep quality, and overall PTSD symptoms. Materials and Methods  We conducted retrospective chart reviews for eight veterans referred to the first author for the treatment of nightmares, who completed N-IRT, including baseline and end-of-treatment measures. The protocol involved a single 60-minute NT-enhanced rescripting session and assigned homework to rehearse the revised dream script, and a follow-up evaluation 4 weeks later. The subjects completed a sleep and nightmare interview developed by the first author and the PTSD Checklist at baseline and after the intervention at the follow-up evaluation. Paired t -tests were conducted to test for pre-to-post differences. Results  In the statistical analysis, we observed a statistically significant and clinically meaningful reduction in the frequency ( p  = 0.04) and intensity of nightmares ( p  = 0.001) from pretreatment to the 1-month follow-up. Measures of nightmare-associated emotional distress, the ability to cope with nightmares, sleep duration and sleep efficiency, as well as overall PTSD symptoms also demonstrated significant improvements. Conclusion  These pilot data provide compelling preliminary evidence that a single-session IRT intervention modified with NT (N-IRT) is effective in reducing nightmare frequency and intensity, reducing nightmare distress, improving the act of coping with nightmares, and improving sleep quality and overall PTSD symptoms in veterans. Further investigation of this method with gold-standard clinical trial designs and larger sample sizes is indicated to confirm effectiveness and to better understand the possible mechanisms of treatment effect.

Psychosocial treatments for nightmares in adults and children: a systematic review

BACKGROUND

As nightmares may be a risk factor for, or symptom of, multiple psychological disorders, some researchers suggest that nightmares should be screened, diagnosed, and treated. Treatments for nightmares include trauma-focused Cognitive Behavioural Therapy and Image Rehearsal Therapy, and pharmacological interventions such as prazosin and nitrazepam. As recent research has put into question our current understanding of treatment efficacy, there is a need to systematically review findings related to the effectiveness of nightmare treatments to inform best practice. The current review assessed the efficacy of psychosocial treatments of nightmare in all cohorts.

METHODS

A systematic search of four databases for peer reviewed journal articles from 2000 onwards produced 69 (35 RCTs, 34 non-RCTs) eligible articles that underwent narrative synthesis.

RESULTS

The results provide strong evidence for exposure and image rehearsal treatments for the reduction of nightmare frequency, severity, and distress, in civilian, military, idiopathic, and posttraumatic stress disorder (PTSD) cohorts. There is emerging evidence that self-guided and brief treatment modalities offer efficient and effective treatment options. There is an urgent need for clinical trials of treatment effectiveness in children.

CONCLUSIONS

The results suggest that treatments for nightmares are most effective when they facilitate a sense of control or mastery by directly targeting the nightmare content and/or the client's emotional responses to the nightmare content.

TRIAL REGISTRATION

A review protocol was registered with PROSPERO (CRD42020204861).

Enhancing imagery rehearsal therapy for nightmares with targeted memory reactivation

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. We here used targeted memory reactivation (TMR) during REM sleep to strengthen IRT-related memories and accelerate remission of ND. Thirty-six patients with ND were asked to perform an initial IRT session and, while they generated a positive outcome of their nightmare, half of the patients were exposed to a sound (TMR group), while no such pairing took place for the other half (control group). During the next 2 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 was used as the primary outcome measure. We found that the TMR group had less frequent nightmares and more positive dream emotions than the control group after 2 weeks of IRT and a sustained decrease of nightmares after 3 months. By demonstrating the effectiveness of TMR during sleep to potentiate therapy, these results have clinical implications for the management of ND, with relevance to other psychiatric disorders too. Additionally, these findings show that TMR applied during REM sleep can modulate emotions in dreams.

Characteristics of Posttraumatic Nightmares and Their Relationship to PTSD Severity Among Combat Veterans With PTSD and Hazardous Alcohol Use

ABSTRACT

Although nightmares are known to predict the clinical course of posttraumatic stress disorder (PTSD), research on the relationship between specific nightmare characteristics and PTSD severity is sparse. This study conducted a secondary analysis to explore how five nightmare characteristics are cross-sectionally related to PTSD severity in 76 combat veterans with PTSD and at-risk alcohol use. Consistent with emotional processing theory, we hypothesized that more replicative, threatening, realistic, and easily recalled nightmares would be associated with more severe PTSD, whereas those with greater symbolism would predict lower PTSD severity. Nightmares narratives were audio-recorded and rated by multiple coders. Multiple analyses of variance explored the relationship between nightmare characteristics and PTSD clinical indicators. Most nightmares were realistic, easily recalled, and involved significant threat. Greater realism and replication were associated with greater PTSD severity. Realistic and replicative nightmares may be markers of more severe PTSD and may indicate that less emotional processing of the trauma has occurred.

Sleep Complaints Among School Children

Sleep complaints are common among children. These include both night-time and daytime symptoms, such as trouble falling asleep, problems in maintaining sleep, snoring, and unusual events during sleep and daytime functioning impairment. However, sleep complaints in children are often overlooked and undertreated in clinical practice. Untreated sleep problems may further impact on children's development and will persist into adulthood in some cases. This review summarizes the common sleep complaints and disorders in school children, and provides an overview of the epidemiology, clinical features, consequences, and treatment of the sleep problems.

Targeted Memory Reactivation During REM Sleep in Patients With Social Anxiety Disorder

BACKGROUND

Social anxiety disorder (SAD) is characterized by a significant amount of fear when confronted to social situations. Exposure therapy, which is based on fear extinction, does not often lead to full remission. Here, based on evidence showing that rapid eye movement (REM) sleep promotes the consolidation of extinction memory, we used targeted memory reactivation (TMR) during REM sleep to enhance extinction learning in SAD.

METHODS

Forty-eight subjects with SAD were randomly assigned to two groups: control or TMR group. All patients had two successive exposure therapy sessions in a virtual reality (VR) environment, where they were asked to give a public talk in front of a virtual jury. At the end of each session, and only in the TMR group (N = 24), a sound was paired to the positive feedback phase of therapy (i.e., approval of their performance), which represented the memory to be strengthened during REM sleep. All participants slept at home with a wearable headband device which automatically identified sleep stages and administered the sound during REM sleep. Participants' anxiety level was assessed using measures of parasympathetic (root mean square of successive differences between normal heartbeats, RMSSD) and sympathetic (non-specific skin conductance responses, ns-SCRs) activity, and subjective measures (Subjective Units of Distress Scale, SUDS), during the preparation phase of their talks before (T1) and after (T2) one full-night's sleep and after 1 week at home (T3). Participants also filled in a dream diary.

RESULTS

We observed an effect of time on subjective measures of anxiety (SUDS). We did not find any difference in the anxiety levels of the two groups after 1 week of TMR at home. Importantly, the longer the total duration of REM sleep and the more stimulations the TMR group had at home, the less anxious (increased RMSSD) these participants were. Finally, fear in dreams correlated positively with ns-SCRs and SUDS at T3 in the TMR group.

CONCLUSION

TMR during REM sleep did not significantly modulate the beneficial effect of therapy on subjective anxiety. Yet, our results support that REM sleep can contribute to extinction processes and substantiate strong links between emotions in dreams and waking stress levels in these patients.

Nightmare Rescripting: Using Imagery Techniques to Treat Sleep Disturbances in Post-traumatic Stress Disorder

Besides affecting 8% of the general population, nightmares are one of the most frequent symptoms of traumatized individuals. This can be a significant factor in the treatment of post-traumatic disorders; indeed, several studies demonstrated its strong predictive and prognostic value. Sleep disorders, nightmares in particular, could be very distressing for individuals and need targeted interventions, especially if they are associated with a PTSD diagnosis. To date, the best technique for the treatment of traumatic sleep disturbances seems to be Imagery Rehearsal Therapy (IRT), an empirically supported method. Through a review of the literature on this matter, this article aims to outline the incidence and consequences of nightmares in PTSD, illustrate how IRT could prove useful in their treatment, and investigate its clinical applications.

Imagery Rescripting and Imaginal Exposure in Nightmare Disorder Compared to Positive Imagery: A Randomized Controlled Trial

INTRODUCTION

Both imagery rescripting and imaginal exposure have been proven to be effective in the treatment of chronic nightmares when compared to a waitlist condition. Little is known about their comparative efficacy and their efficacy compared to an active control.

OBJECTIVE

The aims of this study were to compare the two treatments to one another and to positive imagery as an active control, and to explore covariates of the treatment effect.

METHODS

In this single-blinded randomized controlled trial, 96 patients with nightmare disorder (idiopathic nightmares) from an outpatient clinic were randomly assigned to a single individual treatment session of rescripting, exposure, or positive imagery and 4 weeks of practice at home. The primary outcome was nightmare distress, and the secondary outcomes were nightmare frequency, nightmare effects, self-efficacy, and general psychopathology.

RESULTS

Nightmare distress was reduced in all groups (imagery rescripting: Cohen's d = -1.04, imaginal exposure: d = -0.68, positive imagery: d = -0.57), as were nightmare frequency, nightmare effects, and psychopathology. Self-efficacy was enhanced. No differential treatment effects were found on any primary or secondary measure. Treatment gains were not associated with demographic or disorder characteristics, baseline values, treatment credibility, or the number of practice sessions.

CONCLUSIONS

Even short nightmare treatments are effective regardless of personal characteristics, and different interventions produce similar results. Future research should aim to clarify the mechanisms of action. Health care should make more use of these powerful and easy-to-administer nightmare treatments.

Nightmares in Migraine: A Focused Review

Nightmares usually occur during the sleep phase of rapid eye movement (REM) and are associated with some physical symptoms, including sweating, shortness of breath, and lower limb movements. Emotions of fear, anger, shame, and sadness may also accompany nightmares. These symptoms can occur during dreaming, upon awakening, or later when the dream experience is recollected. Nightmares may sporadically occur for everyone, but nightmare disorders are associated with features of impaired mental and physical health and require professional medical treatment. The occurrence of nightmares with several disorders has been reported in the literature, but in migraines it has only been investigated in a small number of studies. Considering the existing relationship between sleep disorders and migraine, the occurrence of nightmares in migraine can negatively affect this association and elevate the risk of depression and anxiety. This, in turn, further reduces the quality of life of affected individuals. Hence, expanding the knowledge on the link between nightmares and migraine, promoting an acceptable quantity and quality of sleep through pharmacological and nonpharmacological interventions in the management of nightmares in migraine, and further scientific investigation of the biopsychosocial mechanisms underlying the link, will be highly valuable for optimal care. This focused review, therefore, gives a brief overview of the current understanding of nightmares in migraine to highlight the open questions and value of further research. The ultimate goal is to contribute to timely recognition and sufficient action to offer beneficial outcomes for affected patients.

Local Neuronal Synchronization in Frequent Nightmare Recallers and Healthy Controls: A Resting-State Functional Magnetic Resonance Imaging Study

Nightmares are highly dysphoric dreams that are well-remembered upon awakening. Frequent nightmares have been associated with psychopathology and emotional dysregulation, yet their neural mechanisms remain largely unknown. Our neurocognitive model posits that nightmares reflect dysfunction in a limbic-prefrontal circuit comprising medial prefrontal and anterior cingulate cortices, hippocampus, and amygdala. However, there is a paucity of studies that used brain imaging to directly test the neural correlates of nightmares. One such study compared the regional homogeneity (ReHo) of resting-state functional magnetic resonance imaging blood-oxygen level-dependent signals between frequent nightmare recallers and controls. The main results were greater regional homogeneity in the left anterior cingulate cortex and right inferior parietal lobule for the nightmare recallers than for the controls. In the present study, we aimed to document the ReHo correlates of frequent nightmares using several nightmare severity measures. We acquired resting-state functional magnetic resonance imaging data from 18 frequent nightmare recallers aged 18-35 (3 males and 15 females) and 18 age- and sex-matched controls, as well as retrospective and prospective disturbed dreaming frequency estimates and scores on the Nightmare Distress Questionnaire. While there were inconsistent results for our different analyses (group comparisons, correlational analyses for frequency estimates/Nightmare Distress scores), our results suggest that nightmares are associated with altered ReHo in frontal (medial prefrontal and inferior frontal), parietal, temporal and occipital regions, as well as some subcortical regions (thalamus). We also found a positive correlation between retrospective disturbed dreaming frequency estimates and ReHo values in the hippocampus. These findings are mostly in line with a recent SPECT study from our laboratory. Our results point to the possibility that a variety of regions, including but not limited to the limbic-prefrontal circuit of our neurocognitive model, contribute to nightmare formation.

Exposure, Relaxation, and Rescripting Therapy for Trauma-Related Nightmares With Psychiatric Inpatients: A Case Series

Research has shown that posttraumatic stress disorder (PTSD) is a highly prevalent diagnosis for psychiatric patients, yet individualized care and treatment is limited in the inpatient acute care sector. Two case studies are presented which examine the use of Exposure, Relaxation, and Rescripting Therapy (ERRT) for chronic trauma-related nightmares, within a private acute care inpatient psychiatric hospital setting. ERRT is empirically supported with efficacy for veteran and civilian populations, however no research to date has been conducted with psychiatric inpatients. Two participants diagnosed with PTSD, suffering distressing trauma-related nightmares, completed ERRT over three sessions during their psychiatric hospital admission, with the aim of reducing the frequency and severity of nightmares and related psychological symptoms. PTSD, depression, sleep quality and quantity, and nightmare frequency and related distress, were measured pre-treatment, during treatment, and follow-up at one, 3 and 6 months. Only one participant reported ongoing nightmares by the third week of the intervention, with both participants reporting an absence of nightmares at the one and 3-month follow-ups, but mixed results by the 6-month follow-up. One participant also reported a reduction in PTSD symptoms and a mild improvement in depression. The results offer some preliminary support for the provision of ERRT for the treatment of trauma-related nightmares for psychiatric inpatients.

Nightmare distress revisited: Cognitive appraisal of nightmares according to Lazarus' transactional model of stress

Aim of the current research was to newly conceptualize nightmare distress. The special focus was on the appraisal of nightmare distress while applying a theory-driven approach based on Lazarus' transactional model of stress. It was argued that individuals feel the more distressed the more they feel threatened and harmed by their nightmares (primary appraisal according to Lazarus) and the more they lack of adequate coping skills to deal with the stressor (secondary appraisal). Based on these assumptions, the questionnaire of Cognitive Appraisal of Nightmares (CAN) was challenged empirically in two studies of patients who have experienced distressing nightmares using explorative and confirmative factor analyses (N = 504 and N = 402). Items and scales showed good psychometric properties and plausible correlations. The CAN sum score was more distinct from nightmare frequency than the frequently used Nightmare Distress Questionnaire (NDQ), underpinning that frequency and distress are both different approaches to what patients suffer from. The NDQ was particularly associated with acted out behaviors after a nightmare, while the CAN was particularly associated with physiological and emotional consequences of a nightmare. In order to obtain a multifactorial and theory-driven picture about how individuals appraise their nightmares, the CAN may be convenient.

Telephone-guided imagery rehearsal therapy for nightmares: Efficacy and mediator of change

The currently best‐supported psychological treatment for nightmares is imagery rehearsal therapy. The problem, however, is that not enough trained practitioners are available to offer this treatment. A possible solution is to conduct imagery rehearsal therapy in a guided self‐help format. In the current study, 70 participants with nightmares according to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders were randomized to either telephone‐guided imagery rehearsal therapy (n = 36) or a wait‐list condition (n = 34). Participants in the imagery rehearsal therapy condition received three sessions over the course of 5 weeks. Every treatment session was followed by telephone support delivered by postgraduate students. Participants who received imagery rehearsal therapy showed larger improvements on nightmare frequency (d = 1.03; p < .05), nightmare distress (d = 0.75; p < .05) and insomnia severity (d = 1.12; p < .001) compared with the participants in the wait‐list condition. The effects were sustained at 3‐ and 6‐month follow‐up. No significant effects were observed on the number of nights with nightmares per week, anxiety and depression. In line with earlier reports, the treatment effect was mediated by the increase of mastery at mid‐treatment, underlining the mechanistic value of mastery in imagery rehearsal therapy. The present study demonstrates that it is possible to deliver imagery rehearsal therapy in a self‐help format supported by unexperienced therapists and with relatively little time investment. This opens possibilities in terms of cost‐effectiveness, scalability and dissemination of imagery rehearsal therapy in the treatment of nightmares.

My Dream, My Rules: Can Lucid Dreaming Treat Nightmares?

Nightmares are defined as repeated occurrences of extremely dysphoric and well-remembered dreams that usually involve subjective threats to survival, security, or physical integrity. Generally, they occur during rapid eye movement sleep (REMS) and lead to awakenings with distress and insufficient overnight sleep. Nightmares may occur spontaneously (idiopathic) or as recurrent nightmares. Recurrent nightmares cause significant distress and impairment in occupational and social functioning, as have been commonly observed in post-traumatic stress disorder, depression and anxiety. By contrast, during lucid dreaming (LD), subjects get insight they are dreaming and may even control the content of their dreams. These features may open a way to help those who suffer from nightmare disorder through re-significations of the dream scene, i.e., knowing that they are dreaming and having control over their dream content. Thus, lucid dreamers might be able to render nightmares normal dreams, thereby assuring a restoring sleep. The aim of the present study is to review the existing literature of the use of LD as an auxiliary tool for treatment of nightmares. We conducted a careful literature search for eligible studies on the use of LD treatment for nightmares. We observed that whereas LD may be a feasible aid in the treatment of patients with nightmares through minimizing their frequency, intensity and psychological distress, the available literature is still scarce and does not provide consistent results. We conclude therefore that more research is clearly warranted for a better estimation of the effective conductance and therapeutic outcome of LD treatment in clinical practice.

Mediators of Change in Imagery Rescripting and Imaginal Exposure for Nightmares: Evidence From a Randomized Wait-List Controlled Trial

Imagery rescripting (IR) and imaginal exposure (IE) are two efficacious treatments for nightmare disorder, but their discrete underlying mechanism(s) remain largely unknown. We therefore examined mediators of the treatment effects of IR and IE in a randomized wait-list controlled trial (N = 104). Therapeutic outcomes were assessed at pre- and post-assessment, and mediator assessment took place in between treatment sessions to establish a temporal relationship between mediators and nightmare symptoms (i.e., frequency and distress). In line with the hypothesis, enhanced mastery (or self-efficacy) of the nightmare content mediated the therapeutic efficacy of IR. Furthermore, the treatment effects of IE were mediated by increased tolerability of the negative emotions elicited by nightmares. Even though IR and IE for nightmares seem to produce similar therapeutic effects, the results of this study suggest that IR and IE tap into different underlying processes.

Aetiology and treatment of nightmare disorder: State of the art and future perspectives

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.

Management of Post-Traumatic Nightmares: a Review of Pharmacologic and Nonpharmacologic Treatments Since 2013

PURPOSE OF REVIEW

Post-traumatic nightmares (PTN) are a common and enduring problem for individuals with post-traumatic stress disorder (PTSD) and other clinical presentations. PTN cause significant distress, are associated with large costs, and are an independent risk factor for suicide. Pharmacological and non-pharmacological treatment options for PTN exist. A previous review in this journal demonstrated that Prazosin, an alpha blocker, was a preferred pharmacological treatment for PTN and imagery rescripting therapy (IRT) was a preferred non-pharmacological treatment. Since that time, new and important research findings create the need for an updated review.

RECENT FINDINGS

Based on the results of a recent study in the New England Journal of Medicine, Prazosin has been downgraded by both the American Academy of Sleep Medicine (AASM) and the Veterans Health Administration/Department of Defense (VA/DoD) for PTN. In Canada, Nabilone, a synthetic cannabinoid, appears to be promising. Few recent studies have been published on non-pharmacological interventions for PTN; however, recent data is available with regard to using IRT on an inpatient setting, with German combat veterans, and through the use of virtual technology. Recent evidence supports the use of exposure, relaxation, and rescripting therapy (ERRT) with children and individuals with comorbid bipolar disorder and PTN. Prazosin is no longer considered a first-line pharmacological intervention for PTN by AASM and VA/DoD. However, in the absence of a suitable alternative, it will likely remain the preferred option of prescribers. IRT and ERRT remain preferred non-pharmacological treatments of PTN. Combining cognitive behavior therapy for insomnia (CBT-I) with IRT or ERRT may lead to improved outcomes.