Michael Schredl

Central Institute of Mental Health | CIMH · Wissenschaftliches Schlaflabor

Environmental and genetic risk factors contribute to the development of borderline personality disorder (BPD). We conducted the largest GWAS of BPD to date, meta-analyzing data from 12,339 cases and 1,041,717 controls of European ancestry, and identified six independent associated genomic loci. Gene-based analysis identified nine risk genes. We obs...

Previous research indicated that the prevalence of frequent nightmares and/or the presence of a nightmare disorder is quite high in patients with mental disorders. In the present study, 75 randomly selected psychiatric inpatients were interviewed and completed questionnaires regarding nightmares, sleep, and psychopathology. The percentage of patien...

Every human dreams; however, individuals differ in terms of how often they can remember some kind of dream experience. This study investigates the relationship between sleep duration and dream recall, including the phenomenon of “white dreaming.” A sample comprising 1080 patients with sleep disorders (age 44.77 ± 17.12 years) and 6530 nights was in...

Nightmares, defined as extremely dysphoric dreams, can cause significant distress in everyday life if they occur frequently. Their aetiology is based on a disposition‐stress model. As elite athletes often experience high stress levels, the present study investigated factors that might be associated with nightmare frequency in a large cohort of 2297...

A vast number of empirical findings support the continuity hypothesis of dreaming. Interestingly, research on that topic in adolescents is scarce. In a sample of 100 adolescents (50 female, 50 male) with a mean age 15.30 ± 0.80 years, it was found that for all six topics (watching TV, video gaming, social media use, engage in hobbies, caring for pe...

Introduction Smartphone applications (Apps) offer a highly scalable, engaging, and cost-effective approach to improving sleep-promoting behaviors and attitudes. In this randomized wait-list controlled trial, we evaluated the efficacy of a novel smartphone app, the Dein Schlaf Dein Tag app from SleepScore Labs, designed to objectively measure sleep...

Representative surveys indicated that the attitude towards dreams varies greatly: some participants agreed to statements like “Dreams are random nonsense” but others expressed more positive attitudes that dreams might be beneficial. The present online study (N = 1,507 participants) elicited attitude towards dreams, personality (Big Five factors), c...

Music is important to humans; therefore, we would expect according to the continuity hypothesis that dreaming reflects the waking-life musical activity of the person. In this study, we analyzed the long dream series of “Barb Sanders,” who has music as one of her main hobbies. This dream series includes 4,254 dreams recorded between 1960 and 2001. O...

Dreaming plays a part in many of the world’s religions, including Hinduism, Buddhism, Judaism Christianity, and Islam. However, research into what the actual dreams of religious persons look like is very rare. Within a series of 2,055 dreams recorded over more than 30 years by a Benedictine nun, the frequency and content of church dreams were analy...

Previous research has shown that learning procedural tasks enhances REM sleep the following night. Here, we investigate whether complex motor learning affects sleep architecture. An experiment in which twenty-two subjects either learned a motor task (trampolining) or engaged in a control task (ergometer) was carried out in a balanced within-group d...

Research indicates that adults suffering from nightmares rarely seek professional help for their condition. However, nothing is known about the help-seeking behavior in adolescents with frequent nightmares. In a sample of 100 adolescents (50 female, 50 male) with a mean age of 15.30 ± 0.80 years, it was found that none of them ever sought professio...

The diagnosis of a nightmare disorder is based on clinically significant distress caused by the nightmares, e.g., sleep or mood disturbances. In order to understand nightmare etiology better empirical research should focus on studying factors that affect nightmare distress in addition to nightmare frequency. Overall, 2492 persons (1437 woman, 1055...

The results of an online survey of 4,588 demographically diverse American adults provide insight into the questions of (a) who in the general population tends to have sports-related dreams, (b) how does interest in sports relate to dreaming about sports, and (c) what are the typical themes in sports-related dreams? A quantitative and qualitative an...

This study aimed to investigate the efficacy of using hypnotic enhancement of auditory suggestion to induce lucid dreams in inexperienced individuals. Lucid dreaming, a state in which the dreamer becomes aware of their dream state, provides opportunities for personal exploration, sports, and clinical applications. However, the rarity of lucid dream...

In Christian faith, dreams – at least some – have been seen as messages from God; very powerful examples can be found in the Bible. However, empirical research regarding dreams of God is relatively scarce. Four hundred and fifty-two persons participated in the present survey, including a group from theology-related professions (theology students, p...

Research indicated that patients suffering from nightmares are often undertreated. One reason for this gap is that nightmare sufferers themselves often have not sought professional help for their nightmares, and-if they did-it was not very helpful. The current study aimed at studying trait factors (personality, harm avoidance) in relation to the pe...

Several months after COVID-19 many individuals still report persisting symptoms, the so-called 'post-COVID-19 syndrome'. An immunological dysfunction is one of the main pathophysiological hypotheses. As sleep is central to the functioning of the immune system, we investigated whether self-reported pre-existing sleep disturbance might be an independ...

Background Cognitive behavioral therapy for insomnia (CBT-I) is the treatment of choice for chronic insomnia. In the metacognitive model of Ong et al., a current model of the pathogenesis of chronic insomnia, sleep-related metacognitions are considered to be an insomnia-promoting factor. Objective The objective of this study is to investigate the...

Here we examined the possibility of a relationship of sensory processing sensitivity (SPS) with chronotype in a German-speaking sample of N = 1807 (1008 female, 799 male) with a mean age of 47.75 ± 14.41 y (range: 18-97 y). The data were collected using an anonymous online questionnaire (Chronotype: one item of the Morning-Evening-Questionnaire, as...

Several studies explored the association between nightmare frequency and trait (neuroticism and openness) and state (current stress level) factors. The current online study investigated these associations using a nonrepresentative sample (N = 276). It was expected that both state and trait variables impact the nightmare frequency and the hypothesis...

Gender is one of the well-recognized risk factors for idiopathic nightmares, but rarely connected to posttraumatic nightmare characteristics. Thus, this study aims to test gender differences in (posttraumatic) nightmare characteristics after controlling for trauma-related psychopathology in a large sample of people who experienced trauma. Research...

To contribute to the characterization of nightmares in trauma survivors, the Zurich Dream Process Coding System was used to analyze reports of recurrent nightmares from 27 German soldiers with a diagnosis of posttraumatic stress or adjustment disorder who had been admitted to a trauma-related treatment program. Applying a previously developed set o...

Study objectives: The current study investigated nightmare frequency and distress during the pandemic and associated factors. Methods: 1718 participants completed a survey, 747 of which were youth. The MADRE dream questionnaire was used to collect self-reported data on nightmare frequency and distress. In addition, personality traits, current st...

Zusammenfassung Hintergrund Schlaf spielt auch für SportlerInnen eine wichtige Rolle, vor allem vor Wettkämpfen. Ziel der Arbeit In einer Stichprobe von NachwuchsathletInnen soll erfasst werden, ob ein gestörter Schlaf vorliegt und welche Ursachen und Auswirkungen ein gestörter Schlaf vor Wettkämpfen aus subjektiver Sicht hat. Material und Metho...

The majority of adults (50% to 75%) report that they have had at least once recurring dreams in their lives; most of these recurrent dreams, for example, being chased, are negatively toned. However, systematic research regarding the content of these dreams is relatively scarce. Within the present online survey, 676 participants (545 women, 131 men)...

Sleep-related metacognitions play a role in the etiology of insomnia and are distressing while falling asleep. Although similar concepts, such as thought suppression, have been studied in the context of dreaming, the relationship between sleep-related metacognitions and more negatively toned dreaming due to stressful pre-sleep experiences has yet t...

Previous research has shown that Big Five personality factors such as Neuroticism and Openness to Experience are related to both the frequency and severity of nightmares. Recent theoretical and empirical work suggests that trait sensory-processing sensitivity (SPS), characterized by heightened emotional and sensory sensitivity, may better describe...

In a previous questionnaire study with German professional athletes, we showed that the prevalence of lucid dreaming in athletes is 57% and that about 5% of athletes use their lucid dreams to practice sport skills while asleep. The present study applied a Japanese translation of the same questionnaire to a Japanese sample of college athletes to exp...

Cognitive impairment is a common feature in schizophrenia and the strongest prognostic factor for long-term outcome. Identifying a trait associated with the genetic background for cognitive outcome in schizophrenia may aid in a deeper understanding of clinical disease subtypes. Fast sleep spindles may represent such a biomarker as they are strongly...

The present study examined the frequency of core family members (mother, father, brother, and sister) in dreams and their interactions with the dreamer. The dreams were collected via dream diaries. Dream content was analyzed using the Hall and Van de Castle rating system. Overall, 28.9% of the 1,612 dreams reported by 425 participants (361 females...

As dreams reflect waking life, the so‐called continuity hypothesis of dreaming, the literature showing that work‐related stress affects dreams negatively is very plausible. As in waking life, hobbies are an important component in the work–life balance. In the present study, the work–life balance in dreams was studied. Overall, 1695 persons (960 wom...

Dream recall frequency and lucid dream frequency showed large inter-individual differences that are partly related to personality dimensions. However, as dream research is a small field, independent studies are necessary to build a solid empirical foundation. The present online survey included 1,537 participants (1150 women, 387 men) with a mean ag...

Previous research identified personality and neurophysiological traits that are associated with inter-individual differences in lucid dreaming frequency. The present study investigated the question as to whether sensory processing sensitivity is related to lucid dreaming. Overall, 1,807 persons (1,008 woman, 799 men) with a mean age of 47.75 ± 14.4...

Lucid dreams are characterized by the awareness of the dreamer that s/he is dreaming. Typically, if the dreamer can control the dream action, pleasurable activities like flying or having sex are chosen. The present study analyzing lucid and nonlucid dream reports reported by 100 persons confirmed previous findings that lucid dreams contain more pos...

Previous research indicated that dream variables such as dream recall, dream sharing, and nightmares are related to personality traits. However, the overall number of studies in this field is rather small, and this data set serves as a necessary replication. Overall, 819 persons (636 women, 183 men) with a mean age of 27.47 ± 9.32 years participate...

This study considers the relationship between dreaming and race in light of the public protests following the murder of George Floyd on May 25, 2020. Findings are presented from an online survey about dreams and the Black Lives Movement (BLM) gathered from 4,947 demographically diverse American adults sampled between June 15 and June 19, 2020. The...

Although dreams are very private, dreaming has also social components, i.e., dreams are shared quite often. We studied the frequency of how often the dreamer deliberately contacted another person because s/he dreamed about this person, as this might intensify the waking-life bonds with this person. Overall, 2929 participants completed the dream sur...

The lifestyle hypothesis of dream recall emphasizes psychological factors in explaining interindividual differences in dream recall frequency. Recent findings suggest that neurophysiological traits such as default mode network connectivity might also help to explain differences in dream recall. A sample of 1,807 participants (1,008 women, 799 men)...

Many dream content analytic studies focus on dream characters, animals, social interactions and so on, but they rarely analyze the frequency of everyday objects in dreams. In the present paper, the frequency and phenomenology of clock dreams in a dream series of 12,476 dreams of a single male dreamer was analyzed. The clock dreams (0.74% of all dre...

Cats have lived with humankind for millennia, and one would expect—according to the continuity hypothesis of dreaming—that cats also show up in dreams, more often when the relationship is between the cat and a human is closer, for example, when she or he is a cat owner. Previous studies showed that the percentage of dreams that included cats ranges...

Background Since people with nightmares rarely seek help, low-threshold interventions and self-help methods are needed. Among different treatment approaches for nightmares, imagery rehearsal therapy (IRT) is the method of choice. Objective In the current study, the authors tested whether IRT is also effective when applied in a short version, withi...

Even if parasomnias do not directly impair the quality of sleep and recovery, they may represent an important stress factor for the affected individuals. Nightmares may have a negative impact on the daytime mood; pavor nocturnus and sleepwalking are often experienced as embarrassing by adults, and furthermore even damage or injuries may occur. It i...

Sleep disorders may be secondary as a symptom of organic or psychic or psychiatric diseases. These disorders can appear as accompanying or temporary symptoms; however, in the context of chronic diseases, they contribute significantly to the morbidity and maintenance of the disease. In those cases, the treatment of the sleep disorder may have a posi...

In contrast to wakefulness, sleep is characterized by very low motor activity and responsiveness. Body functions and hormone secretion are modulated during sleep. Core body temperature and cortisol secretion are markers of the endogenous rhythm that is synchronized by the suprachiasmatic nucleus with a 24-h-day rhythm. The change of sleep and wakef...

An increased likelihood to fall asleep during the daytime is a frequent symptom in a series of widespread sleep medical diseases, for example, sleep-related breathing disorders. Hypersomnia, such as narcolepsy, and idiopathic (primary) hypersomnia as independent diseases are rather rarely observed. The symptom of excessive daytime sleepiness, howev...

Sharing dreams is a common practice and several motives like emotional relief, entertainment, understanding the dream for doing so have been identified. However, little is known about factors associated with these motives. The present online survey (N = 1585) investigated the associations of the Big5 personality factors with motives for sharing a s...

Previous research found that nightmares are accompanied by strong negative emotions. However, nonnightmare dream content of individuals who frequently suffer from nightmares has never been examined. Eighteen individuals with frequent nightmares (≥1 nightmare/week) and 18 control participants without nightmares (<1 nightmare/month) were examined whi...

Previous research has documented a gender difference in nightmare frequency, with women reporting nightmares more often than men. Several explanations have been suggested but empirical research in this area is scarce. The present online survey was completed by 1,808 participants (1,110 women, 698 men) with a mean age 45.64 ± 15.33 years. The gender...

Social interactions with close persons are very important and one would expect – according to the continuity hypothesis of dreaming – that the dreamer's own children would show up in dreams quite frequently. So far the extent to which dreams include the dreamer’s own children has not been studied systematically. Overall, 1695 persons (960 women, 73...

Romantic relationships are an important part of human life and thus, according to the continuity hypothesis of dreaming, one’s romantic partner should show up in dreams quite frequently. The present study is based on 1612 dream reports provided by 425 students. The findings confirmed the hypothesis that partner dreams are more frequent than ex-part...

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 studen...

Dream lucidity, or being aware that one is dreaming while dreaming, is not an all-or-none phenomenon. Often, subjects report being some variant of “a little lucid” as opposed to completely or not at all. As recent neuroimaging work begins to elucidate the neural underpinnings of lucid experience, understanding subtle phenomenological variation with...

Animal dreams have fascinated mankind for ages. Empirical research indicated that children dream more often about animals than adults and dogs, cats, and horses are the most frequent animals that appear within dreams. Moreover, most dreamer-animal interactions are negative. The present study included 4849 participants (6 to 90 yrs. old) reporting 2...

Zusammenfassung Hintergrund und Fragestellung Schlafbezogene Kognitionen, aber auch schlafbezogene Metakognitionen (Umgang mit Gedanken) spielen in der Ätiologie der Insomnie, vor allem bei der Aufrechterhaltung, eine Rolle. Bisher liegt nur ein englischsprachiger Fragebogen (MCQ-I) mit 60 Items zur Erfassung schlafbezogener Metakognitionen vor. Z...

Anecdotal evidence that lucid dreaming might contribute to mental and physical health has been widely reported in the literature. Empirical research, though, is scarce. A brief questionnaire eliciting self-perceived benefits of lucid dreaming on mental and physical health had been completed by 386 participants who had lucid dream experiences. About...

The book of Josie Malinowksi is a well-written and informative introduction into psychological dream research. After definitions and a brief review of the history of dreaming, the author integrates many of the current theories about dream function, e.g., processing of emotions, Social Simulation theory, or dreaming as playing. In addition, clinical...

The book provides an overview of the entire field of sleep medicine, from the basics of sleep physiology to the diagnosis and treatment of specific sleep disorders. It offers a valuable introduction to the field of sleep medicine, but also serves as a reference work on all aspects of clinical practice, including diagnosis, differential diagnosis an...

About 5% of the adult population report that they suffer from nightmares. Nightmares defined as distressing dreams that often result in awakenings should be differentiated from night terrors, post-traumatic re-enactments, and nocturnal panic attacks. Nightmare etiology is best described by an interaction between disposition and current stressors. F...

Previous studies have reported an association between sleep-related factors such as sleep duration, sleep quality and time of awakening with the cortisol awakening response (CAR). Preliminary evidence suggests that frequent nightmares are associated with a blunted CAR. In the present pilot study we investigated the effect of acute nightmares on the...

Lucid dreams occur quite rarely, so research has focused on different induction methods to increase lucid dream frequency. In the sleep laboratory setting the wake-up-back-to-bed (WBTB) technique in combination with the mnemonic induction of lucid dreams (MILD) technique is very effective. The present study with N = 50 participants in line with pre...

Central nervous hyperarousal is as a key component of current pathophysiological concepts of chronic insomnia disorder. However, there are still open questions regarding its exact nature and the mechanisms linking hyperarousal to sleep disturbance. Here, we aimed at studying waking state hyperarousal in insomnia by the perspective of resting-state...

Dogs have been close human companions for millennia and one would expect—according to the continuity hypothesis of dreaming—that dogs are also quite common in dreams. Previous studies showed that the percentages of dreams that include dogs range from about 1.5% to 5%, but studies relating waking-life experiences with dogs with dreams about dogs hav...

Lucid nightmares are defined as dreams with strong negative emotions in which the dreamer is aware that he or she is dreaming but is unable to change the terrifying plot of the dream and/or is unable to deliberately wake up from it. So far, very little is known about lucid nightmare content. A subsample of a representative survey consisting of 408...

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 signif...

Study objectives: The diagnosis of a nightmare disorder is based on clinically significant distress caused by the nightmares, e.g., sleep or mood disturbances during the day. The question what factors might be associated with nightmare distress in addition to nightmares frequency is not well studied. Methods: Overall, 1474 persons (893 women, 58...

Chronotype refers to individual differences in sleep timing (“owls” and “larks”) and “eveningness” has been associated with nightmares. However, it has not been tested as to whether neuroticism mediates this relationship. Urbanicity refers to being raised in an urban region and/or currently living in an urban region and is associated with heightene...

Lucid dreaming is defined as a dream in which an individual becomes consciously aware that s/he is dreaming while dreaming. Concepts about lucid dreaming vary strongly in different cultures. The present survey was completed by 3,992 Americans 18 years and older in age (2,310 women and 1,682 men), with a mean age of 48.26 ± 17.09 years. Lucid dream...

This study analyzes the responses of 3,031 U.S. adults who, in early May of 2020, completed an online survey regarding their dreams and the COVID-19 outbreak. The results indicate that those people most strongly affected by the pandemic also reported the strongest effects on their dream life (heightened dream recall, more negatively toned dreams, a...

Cross-sectional surveys have indicated that about 5% of the survey participants recorded their dreams at least once a month. Studies have shown that dream recording is related to dream recall frequency, openness to experience, and low conscientiousness, indicating a distinct personality type of dream journalists. The findings of the first longitudi...

The study explored to what extent dreams have been perceived as being helpful in waking life. More specifically, for “important” waking life (conscious) decision-making, the solving of emotional or nonemotional (practical/technical/work-related) problems, forming/changing an attitude about something or somebody, or a conscious behavioral change of...

Background and objectiveNightmares are typically underdiagnosed and undertreated, even though frequent nightmares are quite common in patients with sleep-related breathing disorders. Based on a previous study, we investigated whether patients would respond if they were specifically asked whether they would be interested in telephone counselling abo...

Lucid dreaming is a unique phenomenon with potential applications for therapeutic interventions. Few studies have investigated the effects of lucidity on an individual’s waking mood, which could have valuable implications for improving psychological wellbeing. The current experiment aims to investigate whether the experience of lucidity enhances po...

Disrupted circadian rhythms and sleep patterns are frequently observed features of psychiatric disorders, and especially mood disorders. Sleep deprivation treatment (SD) exerts rapid but transient antidepressant effects in depressed patients and has gained recognition as a model to study quick-acting antidepressant effects. It is of interest how lo...

Professional work is an integral part of modern life. According to the continuity hypothesis of dreaming, which states that dreams reflect waking life, work-related dreams should be quite common. As most dream content analytic studies are carried out in student samples, the topic of work in dreams is understudied. A few small studies indicate that...

A variety of factors contribute to nightmare distress; in addition to nightmare frequency also beliefs about nightmares can be associated with heightened nightmare distress. The study investigated the personality correlates of beliefs about nightmares and whether these beliefs mediate the relationship between gender, neuroticism, and nightmare dist...

Dream lucidity, or the real-time awareness of a dream, is not an all-or-none phenomenon. Often, subjects report being some variant of “a little lucid” as opposed to completely or not at all. As recent neuroimaging work begins to elucidate the neural underpinnings of lucid experience, understanding subtle phenomenological variation within lucid drea...

Models of nightmare aetiology postulate an interaction between trait and state factors. However, most of the studies that support these models have been cross‐sectional and longitudinal studies are scarce. The present data were obtained from N = 888 participants completing two online dream studies carried out independently with the same online pane...

Introduction Lucid dreaming (being aware that one is dreaming) is typically a positive experience that may enhance positive mood even after waking. There is concern, however, that lucid dreaming may interfere with sleep quality. In the current experiment, participants practiced common lucid dream induction techniques over the course of a week, and...

Since the formulation of the continuity hypothesis in 1971, research findings have supported the thematic and emotional continuity between waking and dreaming. However, dreams that include experiences that never occurred in the dreamer’s waking life, this is, discontinuous dreams, have not been studied extensively. In a long series ( N = 11,575 dre...

Books on dreams and dream interpretation have a very long history and still enjoy a wide readership. However, empirical studies regarding this topic are scarce. The present online study (N = 2,492) elicited frequency of reading dream literature and self-rated benefit of this reading. The findings indicate that reading something about dreams is quit...

REM periods with lucid dreaming show increased brain activation, especially in the prefrontal cortex, compared to REM periods without lucid dreaming and, thus, the question of whether lucid dreaming interferes with the recovery function of sleep arises. Cross-sectional studies found a negative relationship between sleep quality and lucid dreaming f...

In addition to a large variety of somatic symptoms, fever also affects cognition, sleep, and mood. In an online survey with 164 participants, 100 fever dream reports were submitted. Fever dreams were more bizarre and more negatively toned and included more references to health and temperature perception compared to “normal” most recent dreams – fin...