Variety and intensity of emotions in nightmares and bad dreams

Nocturnal exposure to a preferred ambient scent does not affect dream emotionality or post-sleep core affect valence in young adults

Emotions experienced within sleep mentation (dreaming) affect mental functioning in waking life. There have been attempts at enhancing dream emotions using olfactory stimulation. Odors readily acquire affective value, but to profoundly influence emotional processing, they should bear personal significance for the perceiver rather than be generally pleasant. The main objective of the present sleep laboratory study was to examine whether prolonged nocturnal exposure to self-selected, preferred ambient room odor while asleep influences emotional aspects of sleep mentation and valence of post-sleep core affect. We asked twenty healthy participants (12 males, mean age 25 ± 4 years) to pick a commercially available scented room diffuser cartridge that most readily evoked positively valenced mental associations. In weekly intervals, the participants attended three sessions. After the adaptation visit, they were administered the odor exposure and odorless control condition in a balanced order. Participants were awakened five minutes into the first rapid eye movement (REM) stage that took place after 2:30 a.m. and, if they had been dreaming, they were asked to rate their mental sleep experience for pleasantness, emotional charge, and magnitude of positive and negative emotions and also to evaluate their post-sleep core affect valence. With rs < 0.20, no practically or statistically significant differences existed between exposure and control in any outcome measures. We conclude that in young, healthy participants, the practical value of olfactory stimulation with self-selected preferred scents for enhancement of dream emotions and post-sleep core affect valence is very limited.

Nightmare distress is related to traumatic childhood experiences, critical life events and emotional appraisal of a dream rather than to its content

Nightmares are a substantial burden for sleep quality. Previous studies have shown that traumatic experiences can increase the probability of nightmares, and also waking-life distress can enhance this effect. There is evidence that the intensity of negative dream emotions is more responsible for rating a dream as a nightmare than threatening dream contents. However, there is still a lack of research concerning effects on nightmare distress. We hypothesise that traumatic childhood experiences (such as emotional abuse, obtained by the Childhood Trauma Questionnaire), critical life events (obtained by the Social Readjustment Rating Scale) and threatening dream contents are associated with nightmare distress. A sample of N = 103 participants kept a dream diary over 28 consecutive days. About 60% of the sample were frequent nightmare dreamers. The participants recorded their violent dream contents and dream emotions in their diary. To predict nightmare distress, regression models were constructed; nightmare distress was measured with the Nightmare Distress Questionnaire. Results showed that emotional abuse in childhood and critical life events predicted nightmare distress. Moreover, violent dream contents were associated with nightmare distress but, after we controlled for nightmare frequency and the intensity of negative dream emotions, the significant impact of violent dream contents decreased. The results suggest that the emotional appraisal of a dream has a substantial influence on nightmares in addition to traumatic childhood experiences and critical life events.

What about dreams? State of the art and open questions

Several studies have tried to identify the neurobiological bases of dream experiences, nevertheless some questions are still at the centre of the debate. Here, we summarise the main open issues concerning the neuroscientific study of dreaming. After overcoming the rapid eye movement (REM) ‐ non‐REM (NREM) sleep dichotomy, investigations have focussed on the specific functional or structural brain features predicting dream experience. On the one hand, some results underlined that specific trait‐like factors are associated with higher dream recall frequency. On the other hand, the electrophysiological milieu preceding dream report upon awakening is a crucial state‐like factor influencing the subsequent recall. Furthermore, dreaming is strictly related to waking experiences. Based on the continuity hypothesis, some findings reveal that dreaming could be modulated through visual, olfactory, or somatosensory stimulations. Also, it should be considered that the indirect access to dreaming remains an intrinsic limitation. Recent findings have revealed a greater concordance between parasomnia‐like events and dream contents. This means that parasomnia episodes might be an expression of the ongoing mental sleep activity and could represent a viable direct access to dream experience. Finally, we provide a picture on nightmares and emphasise the possible role of oneiric activity in psychotherapy. Overall, further efforts in dream science are needed (a) to develop a uniform protocol to study dream experience, (b) to introduce and integrate advanced techniques to better understand whether dreaming can be manipulated, (c) to clarify the relationship between parasomnia events and dreaming, and (d) to determine the clinical valence of dreams.

Brief behavioral treatment for insomnia decreases trauma-related nightmare frequency in veterans

STUDY OBJECTIVES

Trauma-related nightmares are highly prevalent among veterans and are associated with higher severity insomnia and PTSD. Cognitive behavioral therapy for insomnia (CBT-I, typically 6-8 sessions) has been shown to reduce trauma-related nightmares. Brief behavioral treatment for insomnia (BBTI, 4 sessions) has been found to be comparable to CBT-I in decreasing insomnia severity; however, the effects of BBTI on nightmares have not been investigated. The current study tested the effects of BBTI on both trauma-related nightmares and non-trauma-related bad dreams using an active control group, progressive muscle relaxation therapy (PMRT). Additionally, we tested whether baseline trauma-related nightmare frequency and baseline non-trauma-related bad dream frequency moderated changes in insomnia severity.

METHODS

Participants were 91 military veterans with insomnia disorder randomized to BBTI or PMRT. Participants reported insomnia severity on the Insomnia Severity Index and reported trauma-related nightmare frequency and non-trauma-related bad dream frequency on the Pittsburgh Sleep Quality Index--PTSD Addendum.

RESULTS

We found that BBTI significantly reduced trauma-related nightmares from baseline to post-treatment while PMRT did not. However, reductions in trauma-related nightmares were not maintained at six month follow up. Neither BBTI nor PMRT reduced non-trauma-related bad dreams from baseline to post-treatment. We also found that neither baseline trauma-related nightmare frequency nor baseline non-trauma-related bad dream frequency moderated changes in insomnia symptom severity.

CONCLUSIONS

Findings from the current study suggest that BBTI may help to reduce trauma-related nightmares. Further research is needed to better understand potential mechanisms underlying how improved sleep may reduce trauma-related nightmares.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Brief Behavioral Insomnia Treatment Study (BBTI); Identifier: NCT02571452; URL: https://clinicaltrials.gov/ct2/show/NCT02571452.

Nightmares' Pattern and Predictors among a Saudi University Students during COVID-19 Pandemic

Purpose: During the coronavirus disease 2019 (COVID-19) pandemic quarantine, university students were under various types of stressors, including the exams period, which might have affected their quality and quantity of sleep, and consequently, their quality of life. This study aimed to investigate the pattern and predictors of nightmares among university students and coinvestigate the presence of other types of sleep disturbances, mental disorders, and quarantine-related stressors. Methods: This cross-sectional study included 368 university students who answered a self-completed questionnaire covering their sociodemographic features, nightmare indicators, and associated quarantine stressors. Additionally, sleep disturbances were measured using the Generalized Sleep Disturbance Scale (GSDS), anxiety using the Generalized Anxiety Disorder 2 scale, and depression using the Patient Health Questionnaire-2. Results: The participants’ mean age was 20.4 ± 1.6 years, and male participants represented 35.9% of the sample. Nightmares were experienced by 117 (31.8%) of the participants, of whom 44.4% had new-onset nightmares. The mean GSDS was 45.0 ± 14.9 (min. = 12, max. = 130). This value is associated with elevated odds of the following outcomes: the presence of nightmares (odds ratio [OR] = 1.8; confidence interval [CI] 95% = 1.1–3.0); new-onset nightmares at the time of pandemic (OR = 2.6; CI 95% = 1.3–5.5); and anxiety (OR = 1.74; CI 95% = 1.0–2.9). The presence of nightmares elevated the score of GSDS by 11.3 points (S.E. = 1.6, p < 0.001), elevated the odds of anxiety by 4.1 (CI 95% = 2.5–6.8), and depression by 2.1 (CI 95% = 1.3–3.4). Conclusions: Stressors resulting from both the exams period and the fact that it was conducted during COVID-19 quarantine increased the rate and affected the pattern of nightmares. These stressors also led to other sleep disturbances and mental disorders that were significantly more prevalent among females.

Nightmares in Children with Foetal Alcohol Spectrum Disorders, Autism Spectrum Disorders, and Their Typically Developing Peers

Children with Foetal Alcohol Spectrum Disorders (FASD) and Autism Spectrum Disorders (ASD) experience significantly higher rates of sleep disturbances than their typically developing (TD) peers. Pre-sleep anxiety and waking emotional content is known to affect the content and frequency of nightmares, which can be distressing to children and caregivers. This is the first study to analyse nightmare frequency and content in FASD, and to assess its association with psychometric outcomes. Using online caregiver questionnaires, we assessed reports from 277 caregivers of children with ASD (n = 61), FASD (n = 112), and TD children (n = 104) using the Children's Sleep Habits Questionnaire (CSHQ), the Child Behaviour Checklist (CBCL), the Spence Children's Anxiety Scale (SCAS), and the Behaviour Rating Inventory for Executive Functioning (BRIEF). Within the ASD group, 40.3% of caregivers reported their children had nightmares. Within the FASD group, 73.62% of caregivers reported their children had nightmares, and within the TD group, 21.36% of caregivers reported their children had nightmares. Correlation analysis revealed significant associations between anxiety and nightmares, maladaptive behaviour and nightmares, and executive functioning and nightmares in the TD and FASD groups, but not ASD group. This paper adds to the emerging body of work supporting the need for sleep interventions as part of clinical practice with regard to children with ASD and FASD. As a relatively niche but important area of study, this warrants much needed further research.

Dreaming during COVID-19: the effects of a world trauma

On March 11, 2020, the World Health Organization (WHO) declared a state of health emergency affecting the entire world population. Given the serious practical and psychological difficulties and complications that have been experienced during this period, many scholars have created hypothesis, as a consequence, an increased possibility of developing post-traumatic stress disorder (PTSD) within the general population with significant implications for one's dream activity. Participants in the study were recruited via the instant messaging application 'WhatsApp' for a period of 14 days. The study consisted of three phases: the first phase provided information on the purpose of the research and how to carry it out; in the second phase, each participant, using the Bionian model of dream experience as a focus, was asked to write down dreams, emotions and free connections/associations related to the dream. At the end of the collection, the texts obtained were analysed by means of a qualitative analysis performed with the aid of the MAXQDA software. The study confirms the computational and exploratory analysis of the text carried out in the research of Pesonen et al. (2020), finding also in our sample the presence of the hypothesized clusters going to explain the manifestation of imagery related to COVID-19 also within the dream activity. To confirm this, the nightmare of participant number 6 of the study is reported. The following qualitative research has offered an insight into the traumatic nature of the COVID-19 pandemic, showing how many unmetabolized 'daytime elements' have been reproposed in the dream scenario, recalling the symptomatology of PTSD through the presence of distressing content that affect the quality of sleep and the daily life of the individual.

Dreaming in Adolescents During the COVID-19 Health Crisis: Survey Among a Sample of European School Students

According to the continuity hypothesis of dreaming and contemporary psychodynamic approaches, dreams reflect waking life. The aim of the present study was to explore the relationship between the COVID-19 pandemic and dreaming in adolescents. A cross-sectional survey was conducted in Italy, Romania and Croatia involving 2,105 secondary school students (69% girls, mean age 15.6 ± 2.1 years; 31% boys, mean age 15.1 ± 2.2 years; mean age of whole sample 15.4 ± 2.1 years). No substantial differences between countries were found. Thirty-one percent of the participants reported heightened dream recall, 18% noticed an increase in nightmares during the lockdown, and 15% of the provided dreams (n = 498) included pandemic-related content. The results indicate that subjective emotional reactions to lockdown had a significantly higher correlation to dreaming than objective distress (i.e., illness or death of a close one because of COVID-19). These findings suggest that attention to dreams should be included in preventive programs for adolescents with pandemic-related stress.

Psychometric properties of the Disturbing Dream and Nightmare Severity Index-Korean version

STUDY OBJECTIVES

This study aimed to examine psychometric properties of the Disturbing Dream and Nightmare Severity Index (DDNSI) in individuals aged between 18 and 39.

METHODS

All participants (n = 674) were asked to complete the DDNSI, including the modified Nightmare Effects Survey. Additionally, 109 participants were tested for test-retest reliability after 3 months. Among our sample, 229 (33.9%) reported having at least 1 nightmare per month.

RESULTS

Internal consistency was evaluated for the total sample (Cronbach's α = .920) and separately for individuals reporting more than once per month (Cronbach's α = .755). Test-retest reliability after 3 months was .705. Convergent validity of the DDNSI with Nightmare Effects Survey was also satisfactory (r = .638, P < .001). Finally, exploratory factor analysis was conducted to explore the construct of the DDNSI, and results indicated that it consisted of 2 factors, nightmare frequency and nightmare distress [χ²(df) = 2.241(1) ∆χ² (∆df) = 155.575(4), Tucker-Lewis incremental fit index = .980, root mean square error of approximation (90% confidence interval) = .074 (0, .208), standardized root-mean-square residual = .011].

CONCLUSIONS

The DDNSI is a reliable measure of nightmare severity that can be used in various settings.

Prevalence of and factors associated with nightmares in the elderly in a population based cohort study

OBJECTIVES

Nightmares are extremely unpleasant and vivid recurring dreams that are accompanied with awakening during sleep. However, earlier studies were mostly conducted with children and adults, with very few studies on nightmares in older adults. This population-based study aims to investigate the prevalence of nightmares and its associated factors nightmares in the elderly.

METHODS

This study utilized a subsample from the Korean Genome and Epidemiology Study (KoGES). Participants (n = 2940; mean age 63.71 ± 6.73) completed the questionnaires on nightmares (Disturbing Dream and Nightmare Severity Index; DDNSI), depression, suicidal ideation, sleep quality and stress.

RESULTS

Among the sample, 2.7% (n = 79) were classified into the nightmare group (NG), which was classified with DDNSI scores. In the age group over 70, prevalence of nightmares was 6.3% (n = 37), which was significantly higher than other age groups. Marital status, employment status and family income were associated with nightmares. Additionally, NG reported significantly more sleep problems, higher suicidal ideation, depression and stress compared to the non-nightmare group (N-NG). Logistic regression analyses results indicated that the NG was 4.35 times at higher risk for depression, and 3.16 higher risks for stress, and 3.45 higher risks for suicidal ideation compared to the N-NG after controlling for covariates.

CONCLUSIONS

Our results indicate that psychological and demographic factors are associated with nightmares in the elderly. Furthermore, this population-based cohort study showed the prevalence of nightmares increased after age 70, which suggests the need for further studies of nightmares in older populations.

Effects of all-night exposure to ambient odour on dreams and affective state upon waking

Previous laboratory research has shown that exposure to odours of contrasting pleasantness during sleep differentially affects the emotional tone of dreams. In the present study, we sought to investigate how a generally pleasant (vanillin) and unpleasant (thioglycolic acid [TGA]) smell influenced various dream characteristics, dream emotions, and post-sleep core affect during all-night exposure, controlling for appraisal of the olfactory environment during the assessments and sleep stage from which the participants woke up. We expected that exposure to vanillin would result in more pleasant dreams, more positive and less negative dream emotions, and a more positive post-sleep core affect compared to the control condition, whereas exposure to TGA would have the opposite effect. Sixty healthy volunteers (36 males, mean age 24 ± 4 years) were invited to visit the sleep laboratory three times in weekly intervals. The first visit served to adapt the participants to the laboratory environment. On the second visit, half the participants were exposed to an odour (vanillin or TGA, 1:1) and the other half to the odourless control condition. On the third visit, they received control or exposure in a balanced order. On each visit, the participants woke up twice, first from the rapid eye movement (REM) sleep stage and then in the morning, usually from a non-REM sleep stage. Repeated measures were taken upon each awakening. Dream pleasantness, emotional charge of the dream, positive and negative emotions experienced in the dream, and four dimensions of post-sleep core affect (valence, activation, pleasant activation - unpleasant deactivation, and unpleasant activation - pleasant deactivation) were assessed. We found a small effect of condition (exposure vs. control) in interaction with appraisal of the ambient olfactory environment on dream pleasantness. Specifically, false alarms (i.e., perceiving odour in the absence of the target stimulus) were associated with lower dream pleasantness than correct rejections. Although exposure had a statistically significant positive influence on post-sleep core affect (namely, valence, activation, and pleasant activation - unpleasant deactivation), the size of the effect was small and lacked practical significance. The hypothesised differential effects of vanillin and TGA were only modelled for dream ratings because they decreased the fit of the other models. Neither dream pleasantness nor emotionality differed according to the odour used for stimulation. The results of the present study suggest that all-night exposure to odours is unlikely to produce practically significant positive effects on dreams and post-sleep core affect.

The Dreamland: Validation of a Structured Dream Diary

Validated instruments for the analysis of dream contents are still scarce. Therefore, the aim of this study was to validate the Dreamland Questionnaire (DL-Q) by comparing its results to those of the Hall and van de Castle Coding System (HVDC). Twenty-two participants voluntarily filled in a written dream report as well as our DL-Q questionnaire, in total 30 dreams were collected with both measures. Written reports were analyzed with the HVDC and results of the two instruments were compared using Pearson correlations. Results showed that correlations were high for dominant characters, pleasantness of dream content, and body-related experiences. However, some DL-Q items showed low correlations and others could not be compared directly, as the HVDC did not include the same set of items. The DL-Q showed satisfactory validity and reliability as a measure of dream criteria and may serve as an effective tool for diagnosis and evaluation and facilitate future clinical and research studies. Nevertheless, some items could not be compared as part of this study and should be validated in future investigations.

Bad dreams, bedtime anxiety, and trait anxiety in school-aged children

Background and objectives

Occasional nightmares (distressing dreams that awaking the sleeper) and bad dreams (distressing dreams that do not awaking the sleeper) are very common in children and adolescents. About 5% of children experience frequent nightmares (once a week or more often) and the question arises as to what factors contribute to significant nightmare distress which is basic for diagnosing a nightmare disorder.

Materials and methods

A sample of 624 school-aged children (10–16 years; mean age 12.45 ± 1.33 years) completed a dream questionnaire and an anxiety inventory.

Results

About 11% of the participants reported frequent bad dreams; 3.5% reported frequent bedtime anxieties due to bad dreams. Similar to the findings in adults, distress due to bad dreams was not only related to bad dream frequency but also to trait anxiety—controlling for the direct effect of trait anxiety on bad dream frequency, i.e., bad dream frequency and trait anxiety contributed independently to bedtime anxiety due to bad dreams. In the exploratory part, the cultural background of the children’s parents showed only minor effects on bad dreams.

Conclusion

Similar to nightmare studies in adults, bad dream frequency and trait anxiety contributed independently to bad dream distress. Based on the current diagnostic criteria of the nightmare disorder, it would be interesting to have the opportunity to treat children with significant distress due to nightmares or bad dreams and study the long-term benefit—given that many adult nightmare sufferers reported that their nightmares started in childhood.

What Do You Think About Your Dreams? The Construction of a Belief About Dreams Questionnaire

BACKGROUND AND PURPOSE

Nightmare distress (ND) is associated with a broad spectrum of psychopathological conditions such as anxiety, depression and bipolar disorder. Some studies have indicated that dream beliefs play an important role in the occurrence and treatment of nightmare distress. However, existing instruments used to assess dream beliefs either fail to satisfy the requirements of the psychometrics or fail to capture the essence of dream beliefs. This research pursued two objectives: (1) to develop a questionnaire, called the Beliefs About Dreams Questionnaire (BADQ), to measure beliefs people hold about their dreams and (2) to describe the dream beliefs of Chinese college students.

METHODS

The structure and items on the BADQ were based on the previous literature and were the result of an open questionnaire. Some items were deleted through expert review and the result of predict test. To evaluate its validity and reliability, a sample of 1408 Chinese college students from two universities answered the BADQ, the Chinese version of Van Dream Anxiety Scale (CVDAS), the Dream Survey Questionnaire (DSQ), the Patient Health Questionnaire-9 (PHQ-9) and the Generalized Anxiety Disorder-7(GAD-7) Questionnaire. After two weeks, 95 of them answered the BADQ again. Exploratory factor analysis (n=704) and confirmatory factor analysis (n=704) were conducted to explore and verify the structure of BADQ. The correlation between the CVDAS and the BADQ was calculated to evaluate the divergent validity.

RESULTS

The BADQ contains 26 items. Exploratory factor analysis indicated a five-factor structure: Dream omen and health, Dream superstitions, Dream meaninglessness, Dream reality, and Dream attitude. The result of the confirmatory factor analysis also supported the five-factors structure. Acceptable internal consistency (Cronbach's α of all subscales exceeded 0.80) and ordinary to moderate test-retest reliability (the intraclass correlation coefficient of all subscales ranged from 0.467 to 0.713) of the BADQ were presented. Low degree correlation between the CVDAS and the BADQ (ranged from to -0.052 to 0.219) showed that they were two different variables, indicating a good divergent validity.

CONCLUSION

The present investigation revealed moderate to high construct validity and reliability of the BADQ.

Nightmare Themes: An Online Study of Most Recent Nightmares and Childhood Nightmares

STUDY OBJECTIVES

Even though the common diagnostic criteria (ICSD-3, DSM-5) acknowledge that nightmares do not only contain anxiety/fear (definition of the ICD-10) but also other emotions such as grief, disgust, and anger, the definition of a nightmare still focuses on threats to survival, security, or physical integrity. However, empirical studies on nightmare content in larger samples are scarce.

METHODS

The current study elicited 1,216 of the most recent nightmares including childhood nightmares of a population-based sample.

RESULTS

The findings show that nightmares encompass a diversity of different topics, being chased, physical aggression, including death/injury of close persons. Infrequent themes like being the aggressor and suicide are of special interest as they might be related to waking-life psychopathology.

CONCLUSIONS

The variety of nightmare topics clearly indicate that current definitions of nightmare content are too narrow. Future studies should look into nightmare content of persons in whom nightmare disorder has been diagnosed.

The Stress Acceleration Hypothesis of Nightmares

Adverse childhood experiences can deleteriously affect future physical and mental health, increasing risk for many illnesses, including psychiatric problems, sleep disorders, and, according to the present hypothesis, idiopathic nightmares. Much like post-traumatic nightmares, which are triggered by trauma and lead to recurrent emotional dreaming about the trauma, idiopathic nightmares are hypothesized to originate in early adverse experiences that lead in later life to the expression of early memories and emotions in dream content. Accordingly, the objectives of this paper are to (1) review existing literature on sleep, dreaming and nightmares in relation to early adverse experiences, drawing upon both empirical studies of dreaming and nightmares and books and chapters by recognized nightmare experts and (2) propose a new approach to explaining nightmares that is based upon the Stress Acceleration Hypothesis of mental illness. The latter stipulates that susceptibility to mental illness is increased by adversity occurring during a developmentally sensitive window for emotional maturation—the infantile amnesia period—that ends around age 3½. Early adversity accelerates the neural and behavioral maturation of emotional systems governing the expression, learning, and extinction of fear memories and may afford short-term adaptive value. But it also engenders long-term dysfunctional consequences including an increased risk for nightmares. Two mechanisms are proposed: (1) disruption of infantile amnesia allows normally forgotten early childhood memories to influence later emotions, cognitions and behavior, including the common expression of threats in nightmares; (2) alterations of normal emotion regulation processes of both waking and sleep lead to increased fear sensitivity and less effective fear extinction. These changes influence an affect network previously hypothesized to regulate fear extinction during REM sleep, disruption of which leads to nightmares. This network consists of a fear circuit that includes amygdala, hippocampus, and medial prefrontal cortex and whose substantial overlap with the stress acceleration findings allows the latter to be incorporated into a wider, more developmentally coherent framework.

Hearing impairment and nightmares: a theoretical insight

The aim of this article is to address the issue of nightmares in the deaf population, given that there are no documented studies on this matter to the best of our knowledge. The study of nightmares in the deaf population is of high relevance given their specific characteristics (impossibility of verbalisation) and the lack of studies with this population. Nightmares are dreams of negative content that trigger an awakening associated with a rapid return to a full state of alert and a persistent feeling of anxiety and fear, which may cause significant distress. Various studies show that the deaf population has dreams with more negative imagery and emotions, are more exposed to interpersonal traumas and have higher rates of dissociation, than hearing people. These concepts seem to be connected given that, in the presence of traumatic events, dissociation may act as a defence mechanism and nightmares may operate as an adaptive coping strategy.

Nightmares: risk factors among the Finnish general adult population

STUDY OBJECTIVES

To identify risk factors for experiencing nightmares among the Finnish general adult population. The study aimed to both test whether previously reported correlates of frequent nightmares could be reproduced in a large population sample and to explore previously unreported associations.

DESIGN

Two independent cross-sectional population surveys of the National FINRISK Study.

SETTING

Age- and sex-stratified random samples of the Finnish population in 2007 and 2012.

PARTICIPANTS

A total of 13,922 participants (6,515 men and 7,407 women) aged 25-74 y.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Nightmare frequency as well as several items related to socioeconomic status, sleep, mental well-being, life satisfaction, alcohol use, medication, and physical well-being were recorded with a questionnaire. In multinomial logistic regression analysis, a depression-related negative attitude toward the self (odds ratio [OR] 1.32 per 1-point increase), insomnia (OR 6.90), and exhaustion and fatigue (OR 6.86) were the strongest risk factors for experiencing frequent nightmares (P < 0.001 for all). Sex, age, a self-reported impaired ability to work, low life satisfaction, the use of antidepressants or hypnotics, and frequent heavy use of alcohol were also strongly associated with frequent nightmares (P < 0.001 for all).

CONCLUSIONS

Symptoms of depression and insomnia were the strongest predictors of frequent nightmares in this dataset. Additionally, a wide variety of factors related to psychological and physical well-being were associated with nightmare frequency with modest effect sizes. Hence, nightmare frequency appears to have a strong connection with sleep and mood problems, but is also associated with a variety of measures of psychological and physical well-being.

Nightmares affect the experience of sleep quality but not sleep architecture: an ambulatory polysomnographic study

BACKGROUND

Nightmares and bad dreams are common in people with emotional disturbances. For example, nightmares are a core symptom in posttraumatic stress disorder and about 50% of borderline personality disorder patients suffer from frequent nightmares. Independent of mental disorders, nightmares are often associated with sleep problems such as prolonged sleep latencies, poorer sleep quality, and daytime sleepiness. It has not been well documented whether this is reflected in objectively quantifiable physiological indices of sleep quality.

METHODS

Questionnaires regarding subjective sleep quality and ambulatory polysomnographic recordings of objective sleep parameters were collected during three consecutive nights in 17 individuals with frequent nightmares (NM) and 17 healthy control participants (HC).

RESULTS

NM participants reported worse sleep quality, more waking problems and more severe insomnia compared to HC group. However, sleep measures obtained by ambulatory polysomnographic recordings revealed no group differences in (a) overall sleep architecture, (b) sleep cycle duration as well as REM density and REM duration in each cycle and (c) sleep architecture when only nights with nightmares were analyzed.

CONCLUSIONS

Our findings support the observation that nightmares result in significant impairment which is independent from disturbed sleep architecture. Thus, these specific problems require specific attention and appropriate treatment.

Prevalence and correlates of disturbed dreaming in children

Relatively little is known about nightmares and other forms of disturbed dreaming in children. This article reviews the literature on the prevalence and correlates of nightmares in children and highlights key methodological issues in the field. Results show that regardless of how they are defined and measured, nightmares affect a significant proportion of children of all ages and there is some evidence to suggest that nightmare frequency may peak around the age of 10. Gender differences in nightmare frequency, with girls reporting more nightmares than do boys, tend to appear between the ages of 10 and 15. Although nightmares are associated with a range of psychosocial difficulties (e.g., stress, behavioural problems), elevated anxiety and concomitant sleep-related disorders (e.g., sleepwalking) are among the most robust correlates of nightmares. Very few studies have examined nightmare treatment in children, but promising results have been obtained with imagery rehearsal therapy. Overall, research in the field has been hampered by inconsistent definitions for nightmares, by extensive variability in questionnaire items used to measure nightmare frequency, and by a lack of awareness of how using parents versus children as respondents may impact results. Longitudinal studies are needed to better understand how nightmares and their correlates evolve during childhood and adolescence, to delineate their clinical significance, and to develop effective and age-appropriate treatment strategies.

Thematic and content analysis of idiopathic nightmares and bad dreams

STUDY OBJECTIVES

To conduct a comprehensive and comparative study of prospectively collected bad dream and nightmare reports using a broad range of dream content variables.

DESIGN

Correlational and descriptive.

SETTING

Participants' homes.

PARTICIPANTS

Three hundred thirty-one adult volunteers (55 men, 275 women, 1 not specified; mean age = 32.4 ± 14.8 y).

INTERVENTIONS

N/A.

MEASUREMENT AND RESULTS

Five hundred seventy-two participants kept a written record of all of their remembered dreams in a log for 2 to 5 consecutive weeks. A total of 9,796 dream reports were collected and the content of 253 nightmares and 431 bad dreams reported by 331 participants was investigated. Physical aggression was the most frequently reported theme in nightmares, whereas interpersonal conflicts predominated in bad dreams. Nightmares were rated by participants as being substantially more emotionally intense than were bad dreams. Thirty-five percent of nightmares and 55% of bad dreams contained primary emotions other than fear. When compared to bad dreams, nightmares were more bizarre and contained substantially more aggressions, failures, and unfortunate endings.

CONCLUSIONS

The results have important implications on how nightmares are conceptualized and defined and support the view that when compared to bad dreams, nightmares represent a somewhat rarer-and more severe-expression of the same basic phenomenon.

Nightmare frequency, nightmare distress, and psychopathology in female victims of childhood maltreatment

This study investigated the relationships between a history of childhood maltreatment, the frequency of disturbing dreams, their associated distress, and the presence of psychopathology in 352 female undergraduate volunteers. Participants completed questionnaires assessing dream recall, bad dream and nightmare frequency, nightmare distress, psychological well-being, and history of childhood trauma. Four groups were investigated based on the type and severity of childhood maltreatments experienced. Women reporting more severe forms of maltreatment reported higher frequencies of disturbing dreams, higher levels of nightmare distress, and greater psychopathology. Results showed that nightmare distress explains frequency of disturbed dreaming beyond the effect of psychopathology and childhood trauma. The results highlight the importance of assessing waking distress associated with disturbing dreams independently from their actual incidence.

Nightmares: Prevalence among the Finnish General Adult Population and War Veterans during 1972-2007

STUDY OBJECTIVES

To investigate the prevalence of nightmares among the Finnish general adult population during 1972-2007 and the association between nightmare prevalence and symptoms of insomnia, depression, and anxiety in World War II veterans.

DESIGN

Eight independent cross-sectional population surveys of the National FINRISK Study conducted in Finland in 1972, 1977, 1982, 1987, 1992, 1997, 2002, and 2007.

SETTING

Epidemiologic.

PARTICIPANTS

A total of 69,813 people (33,811 men and 36,002 women) age 25-74 years.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

The investigation of nightmare prevalence and insomnia, depression, and anxiety symptoms was based on questionnaires completed by the participants. Among the whole sample, 3.5% of the men and 4.8% of the women reported frequent nightmares (P < 0.0001 for sex difference), but the prevalence was affected by the age of participants and the year of the survey. Nightmare prevalence increased with age, particularly among the men. The number of people reporting occasional nightmares increased roughly by 20% for both sexes from 1972 to 2007 (P < 0.0001). Participants with war experiences reported more frequent nightmares and symptoms of insomnia, depression, and anxiety than participants without such experiences (P < 0.0001).

CONCLUSIONS

Prevalence of nightmares was affected by the sex and age of the participants, and occasional nightmares have become more common in Finland. Exposure to war elevates nightmare prevalence as well as insomnia, depression, and anxiety symptoms even decades after the war; large numbers of war veterans can affect nightmare prevalence on population level.

CITATION

Sandman N; Valli K; Kronholm E; Ollila HM; Revonsuo A; Laatikainen T; Paunio T. Nightmares: prevalence among the Finnish general adult population and war veterans during 1972-2007. SLEEP 2013;36(7):1041-1050.

Disturbed dreaming and sleep quality: altered sleep architecture in subjects with frequent nightmares

Nightmares are intense, emotionally negative mental experiences that usually occur during late-night sleep and result in abrupt awakenings. Questionnaire-based studies have shown that nightmares are related to impaired sleep quality; however, the polysomnographic profile of nightmare subjects has been only scarcely investigated. We investigated the sleep architecture of 17 individuals with frequent nightmares and 23 control subjects based on polysomnographic recordings of a second night spent in the laboratory after an adaptation night. Nightmare subjects in comparison with control subjects were characterized by impaired sleep architecture, as reflected by reduced sleep efficiency, increased wakefulness, a reduced amount of slow wave sleep, and increased nocturnal awakenings, especially from Stage 2 sleep. While these differences were independent of the effects of waking psychopathology, nightmare subjects also exhibited longer durations of REM sleep that was mediated by heightened negative affect. Our results support that nightmares are related to altered sleep architecture, showing impaired sleep continuity and emotion-related increase in REM propensity.

Randomized controlled trials of psychological and pharmacological treatments for nightmares: a meta-analysis

A meta-analysis of treatments for nightmares is reported. The studies were identified by database searches and by an inspection of relevant reference lists. The inclusion criteria were: nightmares as a target problem, studies published in English, use of a randomized controlled trials and reporting of nightmare-relevant outcomes. A total of 19 studies, published between 1978 and 2012 were identified, which included 1285 participants. Effect sizes were calculated as Cohen's d. A statistically significant improvement for all studies combined (d = 0.47, 95% CI = 0.33-0.60, fixed effects model; d = 0.49, 95% CI = 0.32-0.66, random effects model) and for psychological treatments alone (d = 0.48, 95% CI = 0.36-0.60, random) and for prazosin alone (d = 0.50, 95% CI = 0.03-0.96, random) was found. Individual therapy format yielded a higher effect size than a self-help format (p = 0.03). Minimal interventions (relaxation, recording) yielded lower overall effect size than studies offering more extensive interventions (p = 0.02). It is concluded that there are both psychological and pharmacological interventions which have documented effects for the treatment of nightmares.

Combat-related PTSD nightmares and imagery rehearsal: nightmare characteristics and relation to treatment outcome

The characteristics of nightmares of 48 male U.S. Vietnam war veterans with combat-related posttraumatic stress disorder (PTSD), as well as revised dream scripts developed in the course of Imagery Rehearsal therapy, were examined in relation to pretreatment symptomatology and treatment outcome. Features, content, and themes of nightmares and rescripted dreams were coded by 2 independent raters. Nightmares were replete with scenes of death and violence and were predominantly replays of actual combat events in which the veteran was under attack and feared for his life. Although addressing or resolving the nightmare theme with rescripting was associated with a reduction in sleep disturbance, references to violence in the rescripted dream were related to poorer treatment outcome in nightmare frequency; B  = 5.69 (SE = 1.14). The experience of olfactory sensations in nightmares, a possible index of nightmare intensity, was also related to poorer treatment response; B  = 2.95 (SE = 1.06). Imagery rehearsal for individuals with severe, chronic PTSD and fairly replicative nightmares may be most effective when the rescripted dream incorporates a resolution of the nightmare theme and excludes violent details.

The relative contribution of affect load and affect distress as predictors of disturbed dreaming

This is the first study to empirically investigate the heuristic model of dysphoric dreaming proposed by Levin and Nielsen (2007) . Participants indicated their incidence of nightmares (NMs) and bad dreams (BDs) over 21 days, and rated their subsequent distress in daily dream logs. Results support the contention that the 2 constructs identified in the model, affect load (AL) and affect distress (AD), underlie NM production and are active in both the waking and sleeping states. As predicted, AL accounted for more unique variance to the prediction of incidences of disturbed dreaming (DD), whereas AD accounted for more unique variance to the prediction of distress over NMs and BDs. Taken together, these findings are consistent with Levin and Nielsen's (2007) model and bolster earlier findings that suggest that distress about DD remains a crucial component in the relation between DD frequency and waking psychopathology.

Trauma-related dreams of Australian veterans with PTSD: content, affect and phenomenology

OBJECTIVE

Consensus on the parameters of trauma-related dreams required to meet criteria for post-traumatic stress disorder (PTSD) is critical when: (i) the diagnosis requires a single re-experiencing symptom; and (ii) trauma dreams are prevalent in survivors without PTSD.

METHOD

This study investigated the phenomenology of PTSD dreams in 40 veterans, using structured interview and self-report measures.

RESULTS

Dream content varied between replay, non-replay, and mixed, but affect was largely the same as that experienced at the time of trauma across all dream types. ANOVA indicated no difference between dream types on PTSD severity or nightmare distress.

CONCLUSIONS

The findings provide preliminary support for non-replay dreams to satisfy the DSM B2 diagnostic criterion when the affect associated with those dreams is the same as that experienced at the time of the traumatic event.

Nightmare frequency and nightmare topics in a representative German sample

Nightmares are defined as disturbing mental experiences that generally occur during REM sleep and often result in awakening. Whereas the number of publications addressing nightmare frequency and psychopathology, nightmare etiology and treatment is increasing rapidly in the last few years, nightmare content has been studied very rarely in a systematic way, especially in adults. The present study investigated nightmare frequency and the frequency of various nightmare topics in a representative German sample. The five most common themes were falling, being chased, paralyzed, being late, and the deaths of close persons. Even though several effects can be explained by the continuity hypothesis of dreaming, further research is needed to investigate the possible metaphoric relationship between nightmare topics like falling or being chased and waking-life stressors.

Dreamlike mentations during sleepwalking and sleep terrors in adults

BACKGROUND

Sleep terrors and sleepwalking are described as arousals from slow wave sleep with no or poor mental recollection.

OBJECTIVE

To characterize the mental content retrospectively associated with sleep terrors or sleepwalking.

SETTING

University Hospital.

DESIGN

Controlled prospective cohort.

PARTICIPANTS

Forty-three patients referred for severe sleepwalking/sleep terrors (age: 26 +/- 7 y, 46% men, 5 with sleep terrors only, 8 with sleepwalking only, and 30 with both), matched with 25 healthy control subjects.

INTERVENTION

Thirty-eight of the 43 patients (88%) underwent an interview about the frequency, time, behaviors, and mental content associated with the episodes of sleepwalking and sleep terrors, whenever they occurred over a lifetime. The mental contents were classified for complexity (Orlinski score), and for characters, emotions, fortune/misfortune, and social interactions (Hall and Van de Castle categories). Patients and control subjects underwent an overnight video-polysomnogram.

RESULTS

Seventy-one percent of the patients reported at least 1 dreamlike mentation associated with the sleepwalking/sleep terrors episode. The dreamlike mentation action corresponded with the observed behavior. A total of 106 dreamlike mentations were collected (mean: 3 +/- 3.4 dreamlike mentations/patient, range 0-17). Most (95%) dreamlike mentations consisted of a single visual scene. These dreamlike mentations were frequently unpleasant, with aggression in 24% (the dreamer being always the victim), misfortune in 54%, and apprehension in 84%. The patients with dream mentations reported more severe daytime sleepiness.

CONCLUSION

Short, unpleasant dreamlike mentations may occur during sleepwalking/sleep terrors episodes, suggesting that a complex mental activity takes place during slow wave sleep. Sleepwalking may thus represent acting out of the corresponding dreamlike mentation.

Correlates and Treatments of Nightmares in Adults

Nightmares, distressing dreams that primarily arise from REM sleep, are prevalent among the general population and even more so among clinical populations. The frequency of nightmares and related nightmare distress are linked to both sleep disturbance and waking psychopathology. Based on the extant evidence, nightmares appear to be particularly relevant to posttraumatic stress disorder, and may even be implicated in its pathophysiology. Significant advances in treatment have occurred in recent years, with effective pharmacological and psychosocial interventions now available. Despite the progress that has been made, however, more consistent assessment methods and more rigorous study designs are needed to fully understand the causes and consequences of nightmares.

Longitudinal study of nightmares in children: stability and effect of emotional symptoms

Nightmares are defined as dreams with strong negative emotions which awaken the dreamer and are common during childhood: cross-sectional data shows the highest prevalence rates between the ages of five and ten. The present longitudinal study was designed to study the stability of nightmares over the course of 2 years. Sleep questionnaires and Strengths and Difficulties Questionnaires were completed by 851 10-years-old children and their parents, separately. In the total sample, nightmares occurred often in 2.5% (parental estimates) to 3.5% (self estimates of the children). The findings indicate that nightmare stability is considerably high, i.e., nightmare occurrence was predicted by the prevalence the year before (in addition to the concurrent amount of emotional symptoms). Children with 'chronic' nightmares showed more psychopathological symptoms. It would be interesting to follow-up these children in order to investigate whether childhood nightmares are also predictive for adult psychopathology.

The relationship between disturbed dreaming and somatic distress: a prospective investigation

Despite an abundant literature on disturbed dreaming (DD) incidence and psychopathology, little is known about the pathogenesis of these dream disturbances. Recent work strongly suggests that DD distress may be the primary determinant of the relationship between DD and waking psychological impairment. This is the first empirical investigation of the possible role of somatic distress as a crucial pathway in this relationship. A total of 313 college undergraduates completed 3 measures of somatic distress (SCL-90-R Somatization scale, Somatic Interpretations Questionnaire and the Anxiety Sensitivity Index) and then monitored their DD incidence and distress for 21 consecutive days. It was predicted that high levels of somatic distress would be associated with heightened levels of both DD incidence and distress. Although the results were somewhat mixed, individuals who reported more incidents of both bad dreams and nightmares did indeed report higher levels of somatic distress. The results were largely consistent with our predictions and the findings are discussed with regard to recent modeling by in identifying key cognitive diatheses for the development of DD.

Dream content in chronically-treated persons with schizophrenia

Many clinical, laboratory and non-laboratory studies have examined dream content reported by patients with schizophrenia but findings have been variable and inconsistent. Using both questionnaire-based measures and laboratory REM sleep awakenings, we investigated dream content in 14 patients with schizophrenia (mean age=25.5+/-3.2 years) under atypical antipsychotic medication and 15 healthy controls (mean age=22.3+/-4.2 years). The relationship between eye movement density during REM sleep and dream content was also explored. Questionnaire data revealed that when compared to controls, patients with schizophrenia report experiencing a greater number of nightmares but no significant differences were found on other measures including overall dream recall, presence of recurrent dreams, and frequency of specific emotions. 39 dream reports were collected from each group following awakenings from REM sleep. Laboratory dream narratives from the patients were shorter and, after controlling for report length, most significant differences in dream content between the two groups disappeared with the exception of a greater proportion of unknown characters in the participant group. Patients with schizophrenia spontaneously rated their dream reports as being less bizarre than did controls, despite a similar density of bizarre elements as scored by external judges. Finally, both groups had a comparable density of rapid eye movements during REM sleep but a significant positive correlation between eye-movement density and dream content variables was only found in controls. Taken together, the findings suggest that dream content characteristics in schizophrenia may reflect neurocognitive processes, including emotional processing, specific to this disorder.

Nightmares, Bad Dreams, and Emotion Dysregulation

Nightmares—vivid, emotionally dysphoric dreams—are quite common and are associated with a broad range of psychiatric conditions. However, the origin of such dreams remains largely unexplained, and there have been no attempts to reconcile repetitive traumatic nightmares with nontraumatic nightmares, dysphoric dreams that do not awaken the dreamer, or with more normative dreams. Based on recent research in cognitive neuroscience, sleep physiology, fear conditioning, and emotional-memory regulation, we propose a multilevel neurocognitive model that unites waking and sleeping as a conceptual framework for understanding a wide spectrum of disturbed dreaming. We propose that normal dreaming serves a fear-extinction function and that nightmares reflect failures in emotion regulation. We further suggest that nightmares occur as a result of two processes that we term affect load—a consequence of daily variations in emotional pressures—and affect distress—a disposition to experience events with high levels of negative emotional reactivity.

Measuring nightmare and bad dream frequency: impact of retrospective and prospective instruments

Studies on nightmare frequency have yielded inconsistent results. We compared the frequency of nightmares and bad dreams obtained with retrospective methods (annual and monthly estimates) and with two types of prospective measures (narrative and checklist logs). Four hundred and eleven participants completed retrospective estimates of nightmare and bad dream frequency and recorded their dreams in either narrative or checklist logs for 2-5 weeks. When measured prospectively with narrative logs, nightmare frequency was marginally higher than the 1-year estimate (P = 0.057) but not significantly different from the 1-month estimate (P > 0.05). Prospective bad dream frequency was significantly greater than the two retrospective estimates (ps < 0.0005). There were no significant differences in the frequency of nightmares and bad dreams reported prospectively with narrative versus checklist logs (ps > 0.05). However, checklist logs yielded a significantly greater number of everyday dreams per week (P < 0.0001). Taken together, the results provide partial support for the idea that when compared to daily logs, retrospective self-reports significantly underestimate current nightmare and bad dream frequency. Prospective studies of dream recall and nightmare frequency should take into account the type of log used, its duration, and the participants' level of motivation over time.