Treatment of sleep disturbances in trauma-affected refugees: Study protocol for a randomised controlled trial

Examining Barriers to Rehabilitation and Addressing Rehabilitation Needs Among Persons With Forced Migration Experiences: Interdisciplinary Perspectives

Globally, human displacement is at a record high. According to the United Nations High Commissioner for Refugees, 110 million people have been forcibly displaced worldwide owing to persecution, mass conflict, or human rights violations. Conflicts continue to rage in different parts of the world such as Ukraine, Palestine, Sudan, and Tigray. Large-scale political upheaval is also on the rise in many countries such as Haiti, Venezuela, and Iran. Natural disasters fueled by climate change will further contribute to large-scale forced migration. Persons with forced migration experiences (PFMEs) tend to have significant rehabilitation needs because of high risk of physical injuries, mental trauma, and exacerbation of pre-existing health problems during displacement. Rehabilitation practitioners in host countries must be well equipped to address the complex needs of this population. However, there is currently limited literature to guide best practice. In this article, a group of interdisciplinary professionals examine rehabilitation needs among PFMEs, provide examples of established and emerging rehabilitation interventions with PFMEs in the context of asylum and resettlement, identify barriers to accessing rehabilitation services in host countries, and propose avenues for professional advocacy in this area.

Effect of maximal-intensity and high-intensity interval training on exercise capacity and quality of life in patients with acute myocardial infarction: a randomized controlled trial

BACKGROUND

An increase in V̇O2max is important for acute myocardial infarction morbidity, and recurrence rate and intensity have been suggested as important factors in improving V̇O2max.

AIM

The aim of this study was to compare the effects of maximal-intensity interval training (MIIT) and high-intensity interval training (HIIT) on exercise capacity and health-related Quality of Life (HRQoL) in patients with acute myocardial infarction (MI) at low and moderate cardiac risk in cardiac rehabilitation (CR). This study secondarily aimed to compare the effects of hospital-based phase II CR and usual care.

DESIGN

This study is a randomized controlled trial.

SETTING

Outpatient Rehabilitation Setting.

POPULATION

Fifty-nine patients with acute MI were randomly assigned to the MIIT (N.=30) or HIIT (N.=29) group, and 32 to the usual care group.

METHODS

Twice a week, an intervention was conducted for nine weeks in all groups. The maximum oxygen intake (V̇O2max) and MacNew Heart Disease HRQoL were evaluated before and after intervention.

RESULTS

A significant interaction was observed between time and group for V̇O2max (P<0.001). The MIIT group showed greater improvement than those exhibited by the HIIT and usual care groups (P<0.05). Similarly, a significant time and group interaction was observed on the MacNew Global, Physical, and Emotional scales (P<0.05), but not on the social scale (P>0.05).

CONCLUSIONS

Compared to HIIT and usual care, MIIT significantly increased the V̇O2max and was as safe as HIIT in patients with acute MI with low and moderate cardiac risk in CR. Additionally, MIIT and HIIT were superior to usual care in terms of improving the HRQoL.

CLINICAL REHABILITATION IMPACT

Our results suggest that increased intensity in phase II CR could result in better outcomes in terms of V̇O2max increment in patients with acute MI and low and moderate cardiac risk in CR.

Factors affecting adherence to psychotropics in trauma-affected refugees: data from a randomized controlled trial

Non-adherence to psychotropic drugs may reduce treatment effectiveness and may cause exacerbation of illness. Among migrant populations, studies have identified low adherence to psychotropic drugs. This study aimed to identify factors that were associated with the three basic components of adherence: non-initiation, non-implementation (blood sample), and discontinuation in a clinical sample of trauma-affected refugees diagnosed with posttraumatic stress disorder. The data for this study is derived from a randomized controlled trial (n = 108). Based on existing literature, individual sociodemographic and clinical candidate predictor variables that may affect the initiation, continuation, and implementation to psychotropics were selected as exposure variables. Logistic regression was used to assess the risk relation between non-initiation, non-implementation, discontinuation, and the individual sociodemographic and clinical factors. Three factors - level of education, turn-up rate for medical doctor sessions, and discomfort in relation to the psychotropics - were associated with non-initiation, non-implementation, or discontinuation. The relatively small sample size poses a limitation. Furthermore, factors not examined in the current study may have affected non-initiation, non-implementation, and discontinuation. The study identified level of education, turn-up rate for medical doctor sessions, and discomfort in relation to medicine as important factors in relation to treatment with psychotropics in trauma-affected refugees. Factors contributing to a low turn-up rate, and factors that are consequences of a low turn-up rate, as well as communication and trust in the patient-provider interaction need further research attention. Furthermore, there is a need for research on interventions addressing adherence for refugees with mental illness.

The Danish Trauma Database for Refugees (DTD): A Multicenter Database Collaboration-Overcoming the Challenges and Enhancing Mental Health Treatment and Research for Refugees

Mental health of trauma-affected refugees is an understudied area, resulting in inadequate and poorer treatment outcomes. To address this, more high-quality treatment studies that include predictive analyses, long-term evaluations, cultural adaptations, and take account for comorbidities, are needed. Moreover, given the complex intertwining of refugees' health with post-migration stressors and other social factors, it is crucial to examine the social determinants of refugee mental health. The Danish Trauma Database for Refugees (DTD) is a multicenter research database uniting six national centers that provide outpatient treatment for trauma-affected refugees. Through the database, we collect clinical and sociodemographic data from approximately 1200 refugees annually and will merge the database with Danish population register data. The purpose of the DTD is two-fold; clinical and research. The DTD offers data-driven guidance for routine clinical treatment planning of the individual patient, as well as exceptional research opportunities for testing treatment interventions in clinical settings, with larger sample sizes, and more representative heterogeneity of the population. Complex analyses of risk and protective factors, barriers, access to treatment, and societal and transgenerational aspects of trauma are possible with the DTD. This conceptual paper introduces the DTD, the historical background, the development process and implementation strategy, and the associated challenges with developing and running a multicenter database. Most importantly, it highlights the clinical and research potential of the DTD for advancing the understanding and treatment of trauma-affected refugees.

Psychotherapy readiness domains as predictors of psychotherapy outcome in trauma-affected refugees

INTRODUCTION

Little is known about predictors of psychotherapy outcome in trauma-affected refugees. Knowledge on outcome predictors can help clinicians identify patients prior to treatment who are not likely to benefit from standardized psychotherapy and take additional measures to adjust treatment to the individual patient. Given the dynamic nature of psychotherapy readiness domains, they represent potential targets to be worked with in therapy in order to improve outcomes.

METHODS

Psychotherapy readiness domains (locus of control, cognitive functioning, motivation for therapy, and personality functioning) were examined as potential predictors of psychotherapy outcome in trauma-affected refugees. Secondary analyses were conducted on data from a pragmatic randomized controlled trial. Study participants (N = 190) were refugees with PTSD who received flexible manual-based Cognitive Behavioral Therapy (CBT) at a psychiatric outpatient clinic in Denmark. Psychotherapy readiness domains were assessed via semi-structured interviews at the beginning of psychotherapy. Outcome variables were pre-post change in PTSD symptomology and global level of functioning.

RESULTS

Multiple regression analyses revealed that higher motivation for psychotherapy predicted improvement in PTSD symptomology and global level of functioning. Moreover, higher cognitive functioning predicted improvement in global level of functioning.

LIMITATIONS

The predictor rating scales need further psychometric evaluations in cross-cultural contexts.

CONCLUSIONS

These findings highlight the importance of considering motivation in psychotherapy offered to trauma-affected refugees. Further research is needed to identify potential barriers to motivation in this diverse patient population and to determine whether motivational interventions can lead to improved treatment outcomes.

Sleep timing, chronotype, and posttraumatic stress disorder: An individual participant data meta-analysis

Sleep disturbance is a major component of posttraumatic stress disorder (PTSD). The role of circadian disruption is largely overlooked, though many PTSD studies collect proxy markers of circadian timing. This individual participant data (IPD) meta-analysis examined the correlation between sleep timing / chronotype and PTSD severity among individuals diagnosed with PTSD, the standardized mean difference in sleep timing / chronotype for individuals with and without PTSD, and moderators of these relationships. A systematic search was conducted; authors provided IPD for 27 studies and aggregate data for 16 studies (3,011 participants with PTSD; 2,703 participants without PTSD). Two-step meta-analyses were conducted using a random-effects multivariate approach with robust variance estimation. Bedtime and wake time were not significantly associated with PTSD symptoms or diagnosis. Less total sleep time / time in bed was weakly associated with greater PTSD symptoms. Moderator analyses revealed that effect sizes were stronger in certain populations and when using wrist actigraphy to measure sleep timing; however, gap maps revealed few studies in moderator categories with the strongest effects. Only two studies measured chronotype, prohibiting strong conclusions. Our findings indicate that the relationship between sleep timing and PTSD is weak; however, key gaps in the literature warrant further study.

Social zeitgebers and circadian dysrhythmia are associated with severity of symptoms of PTSD and depression in trauma-affected refugees

The relation of aspects of rest-activity patterns, i.e., social zeitgebers, physical activity and circadian rhythm, to the severity of PTSD and depressive symptoms has not previously been studied. Doing so could provide valuable insight into possible targets for treatment. Our study explored these links in a population of 219 trauma-affected refugees diagnosed with PTSD who were seeking treatment. Data regarding social zeitgebers, such as affiliation with the labor market and contact with social network, and symptoms of PTSD and depression were collected from them. Furthermore, their levels of physical activity and circadian rest-activity parameters were calculated from actigraphy data. Bivariate correlation analyses and multiple linear regression analyses were performed to examine various aspects of rest-activity regarding relation to severity of PTSD and depressive symptoms. Several social zeitgebers were associated with severity of PTSD and depressive symptoms. The level of physical activity was unrelated to symptom severity, whereas a rest-activity pattern, with early onset of the most active 10 h, was associated with severity of PTSD, and a circadian rhythm with a large difference between periods of rest and activity was associated with severity of depression. Social zeitgebers, levels of physical activity and circadian rhythm parameters were all associated with each other. Social zeitgebers and circadian rhythm parameters were significantly related to the severity of PTSD and depressive symptoms-a relationship indicating that interventions targeting regularity of daily routines have a potential role in treating PTSD and depression in trauma-affected refugees.Trial registration: ClinicalTrials.gov, ID: NCT02761161, April 27, 2016.

Polysomnographic Sleep and Attentional Deficits in Traumatized North Korean Refugees

INTRODUCTION

Attentional deficits and sleep problems are common in refugees who have experienced trauma. In the present study, we used polysomnography (PSG) to investigate the relationship between attentional deficits and objective measures of sleep structure in traumatized North Korean refugees.

METHODS

We recruited 32 North Korean refugees (mean age = 33.78 ± 14.33 years) and 39 South Korean participants (mean age = 35.03 ± 11.08 years). Sustained attention and divided attention were assessed using the Computerized Attention Test. We conducted an overnight PSG to objectively assess sleep structure. The participants also completed the Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Impact of Event Scale-Revised (IES-R), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI).

RESULTS

The North Korean refugees showed more commission errors (CEs, p < 0.05) and a larger standard deviation (SD) of the reaction time (RT) (p < 0.05) in the sustained attention task compared to the South Korean participants. Furthermore, the North Korean refugees showed a shorter period of wake after sleep onset (WASO, p < 0.01), less time spent in N1 (p < 0.05), and more time spent in N2 (p < 0.05). The larger SD of RT in the sustained attention task in the North Korean refugees was positively correlated with WASO (r = 0.62, p < 0.01) and N1 stage (r = 0.47, p < 0.05) after controlling for age, sex, BDI, BAI, and IES-R.

CONCLUSION

The North Korean refugees showed poorer performance on the sustained attention task. Nocturnal PSG revealed shorter WASO and time spent in N1 in this population, which are independently associated with the preservation of attentional capacity. These data suggest that traumatized refugees may compensate for attentional deficits induced by their traumatic experiences via increased sleep continuity.

Randomized controlled trial of an integrated approach to treating insomnia and improving the use of positive airway pressure therapy in veterans with comorbid insomnia disorder and obstructive sleep apnea

STUDY OBJECTIVES

Cognitive behavioral therapy for insomnia (CBTI) for comorbid insomnia and obstructive sleep apnea (OSA) has had mixed results. We integrated CBTI with a positive airway pressure (PAP) adherence program and tested effects on sleep and PAP use.

METHODS

125 veterans (mean age 63.2, 96% men, 39% non-Hispanic white, 26% black/African American, 18% Hispanic/Latino) with comorbid insomnia and newly-diagnosed OSA (apnea-hypopnea index ≥ 15) were randomized to 5-weekly sessions integrating CBTI with a PAP adherence program provided by a "sleep coach" (with behavioral sleep medicine supervision), or 5-weekly sleep education control sessions. Participants and assessment staff were blinded to group assignment. Outcomes (baseline, 3 and 6 months) included Pittsburgh Sleep Quality Index (PSQI), 7-day sleep diary (sleep onset latency [SOL-D], wake after sleep onset [WASO-D], sleep efficiency [SE-D]), 7-day actigraphy (SE-A), and objective PAP use (hours/night and nights ≥ 4 h). Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), and Functional Outcomes of Sleep Questionnaire-10 (FOSQ-10) were also collected.

RESULTS

Compared to controls, intervention participants showed greater improvement (baseline to 3 and 6 months, respectively) in PSQI (-3.2 and -1.7), SOL-D (-16.2 and -15.5 minutes), SE-D (10.5% and 8.5%), SE-A (4.4% and 2.6%) and more 90-day PAP use (1.3 and 0.9 more hours/night, 17.4 and 11.3 more nights PAP ≥ 4 h). 90-day PAP use at 3 months was 3.2 and 1.9 h/night in intervention versus controls. Intervention participants also had greater improvements in ISI, ESS, and FOSQ-10 (all p < 0.05).

CONCLUSIONS

An intervention integrating CBTI with a PAP adherence program delivered by a supervised sleep coach improved sleep and PAP use in adults with comorbid insomnia and OSA.

TRIAL REGISTRATION

ClinicalTrials.govStudy name: Novel Treatment of Comorbid Insomnia and Sleep Apnea in Older VeteransURL: https://clinicaltrials.gov/ct2/results?cond=&term=NCT02027558&cntry=&state=&city=&dist=Registration: NCT02027558.

Investigating the link between subjective sleep quality, symptoms of PTSD and level of functioning in a sample of trauma-affected refugees

STUDY OBJECTIVES

To examine whether baseline sleep quality is associated with baseline symptoms of posttraumatic stress disorder (PTSD) and level of functioning, and whether baseline sleep quality and improvement of sleep quality are specific predictors of change in PTSD symptoms and level of functioning.

METHODS

Data were derived from a four-armed randomised controlled superiority trial (N=219 trauma-affected refugees). All four groups received treatment as usual consisting of a 10-12 months bio-psycho-social treatment program with an additional differential treatment component added to each arm. We performed bivariate correlation analyses, multiple linear regression analyses and mediation analyses to examine associations between baseline sleep quality, change in sleep quality and treatment response for PTSD symptoms and level of functioning.

RESULTS

Baseline sleep quality correlated with symptoms of PTSD (r = .33) and level of functioning (r=0.15). Baseline sleep quality, improvement of sleep quality and improvement of general well-being were predictors of treatment response for symptoms of PTSD and level of functioning when controlling for age, gender, and baseline symptoms of PTSD and depression.

CONCLUSIONS

We found that good sleep quality at baseline and improvement of sleep quality were predictors of PTSD treatment response. However, treatment response was more closely associated with improvement in general well-being. The results indicate that the effect of improved sleep quality was partly mediated by a more general mental state improvement. Further research is needed to differentiate if a selected subgroup of patients may profit from sleep enhancing treatment.

Imagery rehearsal therapy and/or mianserin in treatment of refugees diagnosed with PTSD: Results from a randomized controlled trial

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.

Effect of a Multi-Layer, Extended-Release Methylphenidate Formulation (PRC-063) on Sleep in Adults with ADHD: A Randomized, Double-Blind, Forced-Dose, Placebo-Controlled Trial Followed by a 6-month Open-Label Extension

BACKGROUND

The effects of stimulant treatment on sleep in adults with attention-deficit/hyperactivity disorder (ADHD) are complex and varied, with some individuals experiencing worsening of sleep but others experiencing improvement.

METHODS

Data from previously reported trials of the clinical efficacy and safety of the long-acting methylphenidate formulation PRC-063 (Adhansia XR^® in the USA; Foquest^® in Canada) in adults with ADHD were used to evaluate patient-reported sleep outcomes, as captured using the Pittsburgh Sleep Quality Index (PSQI) and adverse events of insomnia. The trials comprised 4 weeks of randomized, forced-dose PRC-063 treatment at a dose of 0 (placebo), 25, 45, 70, or 100 mg/day followed by an optional 6 months of open-label PRC-063 treatment at an individually optimized dose of 25-100 mg/day.

RESULTS

At the end of double-blind treatment, PRC-063 (all doses combined; N = 297) showed no significant difference versus placebo (N = 78) in least squares mean change in global PSQI score from baseline (- 0.7 vs. - 1.3; P = 0.0972) or in scores for each of the seven subscales of the PSQI. For patients enrolled in the open-label extension (N = 184), mean ± standard deviation global PSQI score improved from 7.8 ± 3.55 at the end of double-blind treatment to 5.8 ± 3.11 at 1 month and 5.4 ± 3.21 at 6 months (P < 0.0001). A greater proportion of patients were good sleepers (global PSQI score ≤ 5) at the end of the open-label extension (57.3%) than at baseline (20.9%) or at the end of double-blind treatment (26.0%). In a logistic regression analysis, baseline global PSQI score (odds ratio 1.491; P < 0.0001), but not randomized study treatment (P = 0.1428), was a significant predictor of poor sleep (global PSQI score > 5) at the end of double-blind treatment. Adverse event rates for insomnia (15.8 vs. 3.8%) and initial insomnia (6.1 vs. 1.3%) during double-blind treatment were higher for PRC-063 (all doses combined) than for placebo. Two patients receiving PRC-063 in the double-blind study and one patient in the open-label study were withdrawn because of insomnia adverse events.

CONCLUSIONS

Our findings indicate that, on average, PRC-063 had no significant impact on overall sleep quality in adults with ADHD. Although insomnia was observed as an adverse event, when sleep was measured over time as an outcome in its own right for patients receiving dose-optimized PRC-063 open-label, more patients showed improvement in sleep than deterioration. CLINICALTRIALS.

GOV IDENTIFER

NCT02139124 and NCT02168127.

Sleep disorders in migrants and refugees: a systematic review with implications for personalized medical approach

Background

Sleep disorders are very common in migrants and refugees, often as a comorbid disorder to different somatic or psychiatric diagnoses and psychological disturbances such as metabolic syndrome, post-traumatic stress disorder, depression, and anxiety disorders.

Objectives

To review published prevalence rates as well as possible predictors for sleep disturbances in these vulnerable groups, including pre-migration stress, acculturation, and trauma before, during, and after migration, integration, and lifestyle in the host country with implications for predictive, preventive, and personalized medical approach (3PM).

Data sources

Electronic databases PubMed, PsycInfo, and Web of Knowledge were searched using (combined) search terms "migrant," "asylum seeker," "refugee," "sleep disturbances," "sleep disorder," "insomnia," and "sleep wake disorder."

Study eligibility criteria

Peer-reviewed studies from 2000 to 2018 reporting data on prevalence and/or predictors of any measure of sleep disturbance were included.

Participants

Studies on international migrants and refugees, as well as internally displaced populations, were included.

Methods

We conducted a systematic review on the topic of sleep disorders in migrant and refugee populations. Only published articles and reviews in peer-reviewed journals were included.

Results

We analyzed five studies on sleep disorders in migrants, five studies on adult refugees, and three on refugee children and adolescents. Prevalence of sleep disorders in migrants and refugees ranges between 39 and 99%. In migrant workers, stress related to integration and adaptation to the host society is connected to higher risks of snoring, metabolic diseases, and insomnia. Sleep disturbances in refugees are predicted by past war experience. Sleep difficulties in adult and child refugees are strongly correlated to trauma. Torture of parents and grandparents can predict sleep disorders in refugee children, while being accompanied by parents to the host country has a protective effect on children's sleep.

Conclusions and implications

Considering the differences in risk factors, vulnerability, and traumatic life events for different migrant populations, origins of sleep difficulties vary, depending on the migrant populations. Effects on sleep disturbances and sleep quality may be a result of integration in the host country, including changes of lifestyle, such as diet and working hours with implication for OSAS (obstructive sleep apnea) and insomnia. Compared with migrant populations, sleep disturbances in refugee populations are more correlated with mental health symptoms and disorders, especially PTSD (post-traumatic stress disorder), than with psychosocial problems. In juvenile refugee populations, psychological problems and disturbed sleep are associated with traumatic experiences during their journey to the host country. Findings highlight the need for expert recommendations for development of 3P approach stratified in the following: (1) prediction, including structured exploration of predisposing and precipitating factors that may trigger acute insomnia, screening of the according sleep disorders by validated translated questionnaires and sleep diaries, and a face-to-face or virtual setting and screening of OSAS; (2) target prevention by sleep health education for female and male refugees and migrant workers, including shift workers; and (3) personalized medical approach, including translated cognitive behavioral treatment for insomnia (CBT-I) and imagery rehearsal therapy for refugees and telehealth programs for improved CPAP adherence in migrants, with the goal to enable better sleep health quality and improved health economy.

The management of post-traumatic stress disorder and associated pain and sleep disturbance in refugees

More than 68 million people worldwide have been forcibly displaced and one-third of these are refugees. This article offers an overview of the current literature and reviews the epidemiology and evidence-based psychological and pharmacological management of post-traumatic stress disorder (PTSD), sleep disturbance and pain in refugees and asylum seekers. It also considers the relationship between sleep disturbance and PTSD and explores concepts of pain in relation to physical and psychological trauma and distress. During diagnosis, clinicians must be aware of ethnic variation in the somatic expression of distress. Treatments for PTSD, pain and sleep disturbance among refugees and asylum seekers are essentially the same as those used in the general population, but treatment strategies must allow for cultural and contextual factors, including language barriers, loss of freedom and threat of repatriation.

LEARNING OBJECTIVES

After reading this article you will be able to: •

DECLARATION OF INTEREST

None.

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.