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International Journal of Environmental... Dec 2022Nightmares are highly prevalent and distressing for the sufferer, which underlines the need for well-documented treatments. A comprehensive literature review and... (Meta-Analysis)
Meta-Analysis Review
Nightmares are highly prevalent and distressing for the sufferer, which underlines the need for well-documented treatments. A comprehensive literature review and meta-analysis of the effects of different pharmacological placebo-controlled randomized clinical trials, covering the period up to 1 December 2022, was performed. Searches were conducted in PubMed, Embase, Web of Science, PsychInfo, Cinahl, and Google Scholar, resulting in the identification of 1762 articles, of which 14 met the inclusion criteria: pharmacological intervention of nightmares, based on a placebo-controlled randomized trial published in a European language, reporting outcomes either/or in terms of nightmare frequency, nightmare distress, or nightmare intensity, and reporting sufficient information enabling calculation of effect sizes. Most studies involved the effect of the α-adrenergic antagonist prazosin in samples of veterans or soldiers suffering from posttraumatic stress disorder. Other medications used were hydroxyzine, clonazepam, cyproheptadine, nabilone, and doxazosin. The vast majority of studies were conducted in the USA. The studies comprised a total of 830 participants. The Clinician-Administered PTSD Scale was the most frequently used outcome measure. The results showed an overall effect size of Hedges' = 0.50 (0.42 after adjustment for publication bias). The synthetic cannabinoid nabilone (one study) showed the highest effect size ( = 1.86), followed by the histamine H-antagonist hydroxyzine (one study), and prazosin (10 studies), with effect sizes of = 1.17 and = 0.54, respectively. Findings and limitations are discussed, and recommendations for future studies are provided.
Topics: Humans; Dreams; Randomized Controlled Trials as Topic; Prazosin; Adrenergic alpha-1 Receptor Antagonists; Stress Disorders, Post-Traumatic; Hydroxyzine
PubMed: 36613097
DOI: 10.3390/ijerph20010777 -
Current Neuropharmacology 2020The cannabinoids, Δ9 tetrahydrocannabinol and its analogue, nabilone, have been found to reliably attenuate the intensity and frequency of post-traumatic nightmares.... (Review)
Review
The cannabinoids, Δ9 tetrahydrocannabinol and its analogue, nabilone, have been found to reliably attenuate the intensity and frequency of post-traumatic nightmares. This essay examines how a traumatic event is captured in the mind, after just a single exposure, and repeatedly replicated during the nights that follow. The adaptive neurophysiological, endocrine and inflammatory changes that are triggered by the trauma and that alter personality and behavior are surveyed. These adaptive changes, once established, can be difficult to reverse. But cannabinoids, uniquely, have been shown to interfere with all of these post-traumatic somatic adaptations. While cannabinoids can suppress nightmares and other symptoms of post-traumatic stress disorder, they are not a cure. There may be no cure. The cannabinoids may best be employed, alone, but more likely in conjunction with other agents, in the immediate aftermath of a trauma to mitigate or even abort the metabolic changes which are set in motion by the trauma and which may permanently alter the reactivity of the nervous system. Steps in this direction have already been taken.
Topics: Animals; Brain; Cannabinoids; Dreams; Fear; Humans; Memory; Pain; Sleep; Stress Disorders, Post-Traumatic
PubMed: 31934840
DOI: 10.2174/1570159X18666200114142321 -
Frontiers in Neurology 2020Over the past 60 years, the impact of psychotropic drugs on dream recall and content has been scarcely explored. A review of the few existing experimental results on the... (Review)
Review
Over the past 60 years, the impact of psychotropic drugs on dream recall and content has been scarcely explored. A review of the few existing experimental results on the topic leads us to the following conclusions. For antidepressant drugs, in the great majority, they reduce dream recall frequency (DRF), and the improvement of depressive symptoms is associated with an increase of positive emotion in dream content. For sedative psychotropic drugs, their improvement of sleep quality is associated with a reduction of DRF, but the effect on dream content is less clear. Few occurrences of nightmare frequency increase have been reported, with intake of molecules disturbing sleep or with the withdrawal of some psychotropic drugs. Importantly, the impact of psychotropic drugs on rapid eye movement (REM) sleep does not explain DRF modulations. The reduction of intra-sleep awakenings seems to be the parameter explaining best the modulation of DRF by psychotropic drugs. Indeed, molecules that improve sleep continuity by reducing intra-sleep awakenings also reduce the frequency of dream recall, which is coherent with the "arousal-retrieval model" stating that nighttime awakenings enable dreams to be encoded into long-term memory and therefore facilitate dream recall. DRF is nonetheless influenced by several other factors (e.g., interest in dreams, the method of awakening, and personality traits), which may explain a large part of the variability of results observed and cited in this article.
PubMed: 33224081
DOI: 10.3389/fneur.2020.507495 -
Revue Neurologique Oct 2023Since the discovery of REM (Rapid Eye Movement) sleep in 1953, misconceptions have arisen as to the evidence for its adaptive function and its relation to dreams. Eye... (Review)
Review
Since the discovery of REM (Rapid Eye Movement) sleep in 1953, misconceptions have arisen as to the evidence for its adaptive function and its relation to dreams. Eye movements recorded during REM sleep have not been consistently reported to mirror the eye movements predicted by dream reports. But evidence on eye movement and somatic motor expression from patients with REM sleep behavior disorder (RBD) is consistent with dream enacting behavior. The assumption that dreaming occurs only in REM sleep is incorrect, with numerous reports of nonREM dreaming. However, there may be qualitative differences between REM and nonREM dreams. Early studies that suggested a vital role for REM sleep in psychological well-being are refuted by studies of pharmacologically induced partial or complete REM sleep suppression. Studies of sleep across species show that the primitive monotreme mammals, platypus and echidna, have far more REM sleep than any other homeotherm group, whereas birds have far less REM sleep than any other homeotherm group. Human REM sleep amounts are not unusual, are correlated with nonREM sleep durations but are not correlated with intelligence. Across groups of homeotherms, REM sleep time is highly and inversely correlated (r=-0.975, P=0.02) with average core body temperature, suggesting that REM sleep cycles with nonREM sleep to regulate brain temperature during sleep. Cetacean mammals (dolphins and whales) do not have REM sleep despite their very large brain sizes and impressive cognitive abilities. Reports of "REM sleep-like states" in arachnids, cephalopods and in zebrafish larvae are lacking critical evidence that the observed behaviors are occurring during sleep and that the behaviors are homologous to mammalian REM sleep.
Topics: Animals; Humans; Sleep, REM; Dreams; Mythology; Zebrafish; Mammals
PubMed: 37625974
DOI: 10.1016/j.neurol.2023.08.002 -
Neuroscience and Biobehavioral Reviews Dec 2020Dreams are internally generated experiences that occur independently of current sensory input. Here we argue, based on cortical anatomy and function, that dream... (Review)
Review
Dreams are internally generated experiences that occur independently of current sensory input. Here we argue, based on cortical anatomy and function, that dream experiences are tightly related to the workings of a specific part of cortical pyramidal neurons, the apical integration zone (AIZ). The AIZ receives and processes contextual information from diverse sources and could constitute a major switch point for transitioning from externally to internally generated experiences such as dreams. We propose that during dreams the output of certain pyramidal neurons is mainly driven by input into the AIZ. We call this mode of functioning "apical drive". Our hypothesis is based on the evidence that the cholinergic and adrenergic arousal systems, which show different dynamics between waking, slow wave sleep, and rapid eye movement sleep, have specific effects on the AIZ. We suggest that apical drive may also contribute to waking experiences, such as mental imagery. Future studies, investigating the different modes of apical function and their regulation during sleep and wakefulness are likely to be richly rewarded.
Topics: Arousal; Dreams; Humans; Sleep; Sleep, REM; Wakefulness
PubMed: 33002561
DOI: 10.1016/j.neubiorev.2020.09.018 -
Consciousness and Cognition Aug 2020We explore the application of a wide range of sensory stimulation technologies to the area of sleep and dream engineering. We begin by emphasizing the causal role of the... (Review)
Review
We explore the application of a wide range of sensory stimulation technologies to the area of sleep and dream engineering. We begin by emphasizing the causal role of the body in dream generation, and describe a circuitry between the sleeping body and the dreaming mind. We suggest that nearly any sensory stimuli has potential for modulating experience in sleep. Considering other areas that might afford tools for engineering sensory content in simulated worlds, we turn to Virtual Reality (VR). We outline a collection of relevant VR technologies, including devices engineered to stimulate haptic, temperature, vestibular, olfactory, and auditory sensations. We believe these technologies, which have been developed for high mobility and low cost, can be translated to the field of dream engineering. We close by discussing possible future directions in this field and the ethics of a world in which targeted dream direction and sleep manipulation are feasible.
Topics: Dreams; Humans; Physical Stimulation; Sensation; Sleep, REM
PubMed: 32652511
DOI: 10.1016/j.concog.2020.102955 -
Consciousness and Cognition Jan 2024Acetylcholine is a neurotransmitter and neuromodulator involved in a variety of cognitive functions. Additionally, acetylcholine is involved in the regulation of REM... (Review)
Review
Acetylcholine is a neurotransmitter and neuromodulator involved in a variety of cognitive functions. Additionally, acetylcholine is involved in the regulation of REM sleep: cholinergic neurons in the brainstem and basal forebrain project to and innervate wide areas of the cerebral cortex, and reciprocally interact with other neuromodulatory systems, to produce the sleep-wake cycle and different sleep stages. Consciousness and cognition vary considerably across and within sleep stages, with metacognitive capacity being strikingly reduced even during aesthetically and emotionally rich dream experiences. A notable exception is the phenomenon of lucid dreaming-a rare state whereby waking levels of metacognitive awareness are restored during sleep-resulting in individuals becoming aware of the fact that they are dreaming. The role of neurotransmitters in these fluctuations of consciousness and cognition during sleep is still poorly understood. While recent studies using acetylcholinesterase inhibitors suggest a potential role of acetylcholine in the occurrence of lucid dreaming, the underlying mechanisms by which this effect is produced remains un-modelled and unknown; with the causal link between cholinergic mechanisms and upstream psychological states being complex and elusive. Several theories and approaches targeting the association between acetylcholine and metacognition during wakefulness and sleep are highlighted in this review, moving through microscopic, mesoscopic and macroscopic levels of analysis to detail this phenomenon at several organisational scales. Several exploratory hypotheses will be developed to guide future research towards fully articulating how metacognition is affected by activity at the acetylcholine receptor.
Topics: Humans; Metacognition; Acetylcholine; Acetylcholinesterase; Sleep; Dreams; Wakefulness
PubMed: 38042119
DOI: 10.1016/j.concog.2023.103608 -
Sports Medicine and Arthroscopy Review Mar 2022Arthrofibrosis (AF) is an exaggerated immune response to a proinflammatory insult leading to pathologic periarticular fibrosis and symptomatic joint stiffness. The knee,... (Review)
Review
Arthrofibrosis (AF) is an exaggerated immune response to a proinflammatory insult leading to pathologic periarticular fibrosis and symptomatic joint stiffness. The knee, elbow, and shoulder are particularly susceptible to AF, often in the setting of trauma, surgery, or adhesive capsulitis. Prevention through early physiotherapeutic interventions and anti-inflammatory medications remain fundamental to avoiding motion loss. Reliable nonoperative modalities exist and outcomes are improved when etiology, joint involved, and level of dysfunction are considered in the clinical decision making process. Surgical procedures should be reserved for cases recalcitrant to nonoperative measures. The purpose of this review is to provide an overview of the current understanding of AF pathophysiology, identify common risk factors, describe prevention strategies, and outline both nonoperative and surgical treatment options. This manuscript will focus specifically on sterile AF of the knee, elbow, and shoulder.
Topics: Bursitis; Dreams; Humans; Joint Diseases; Knee Joint; Range of Motion, Articular
PubMed: 35113841
DOI: 10.1097/JSA.0000000000000324 -
PloS One 2021The phenomenon of dreaming about the laboratory when participating in a sleep study is common. The content of such dreams draws upon episodic memory fragments of the...
The phenomenon of dreaming about the laboratory when participating in a sleep study is common. The content of such dreams draws upon episodic memory fragments of the participant's lab experience, generally, experimenters, electrodes, the lab setting, and experimental tasks. However, as common as such dreams are, they have rarely been given a thorough quantitative or qualitative treatment. Here we assessed 528 dreams (N = 343 participants) collected in a Montreal sleep lab to 1) evaluate state and trait factors related to such dreams, and 2) investigate the phenomenology of lab incorporations using a new scoring system. Lab incorporations occurred in over a third (35.8%) of all dreams and were especially likely to occur in REM sleep (44.2%) or from morning naps (48.4%). They tended to be related to higher depression scores, but not to sex, nightmare-proneness or anxiety. Common themes associated with lab incorporation were: Meta-dreaming, including lucid dreams and false awakenings (40.7%), Sensory incorporations (27%), Wayfinding to, from or within the lab (24.3%), Sleep as performance (19.6%), Friends/Family in the lab (15.9%) and Being an object of observation (12.2%). Finally, 31.7% of the lab incorporation dreams included relative projections into a near future (e.g., the experiment having been completed), but very few projections into the past (2.6%). Results clarify sleep stage and sleep timing factors associated with dreamed lab incorporations. Phenomenological findings further reveal both the typical and unique ways in which lab memory elements are incorporated de novo into dreaming. Identified themes point to frequent social and skillful dream scenarios that entail monitoring of one's current state (in the lab) and projection of the self into dream environments elaborated around local space and time. The findings have implications for understanding fundamental dream formation mechanisms but also for appreciating both the advantages and methodological pitfalls of conducting laboratory-based dream collection.
Topics: Adult; Dreams; Female; Humans; Laboratories; Male; Memory, Episodic; Mental Recall; Polysomnography; Sleep; Sleep Stages; Sleep, REM; Young Adult
PubMed: 34614021
DOI: 10.1371/journal.pone.0257738 -
Acta Bio-medica : Atenei Parmensis May 2022The ability to remember dreams can depend on a wide range of factors such as personality, creativity, mental state, cognitive functions as well as somatic symptoms. In...
The ability to remember dreams can depend on a wide range of factors such as personality, creativity, mental state, cognitive functions as well as somatic symptoms. In the course of their studies, medical researchers have demonstrated that about 80% patients, woken up at their Rapid Eye Movement (REM) sleep phase, can remember their own dreams, whereas, in clinical practice, young adults can remember their dreams on their awakenings only once or twice a week. Let us now come to the point: in this study we suggest some hypotheses that could explain the reason why patients suffering from psychosomatic disorders seem to remember dreams much less frequently than healthy individuals.
Topics: Cognition; Dreams; Humans; Mental Recall; Psychophysiologic Disorders; Sleep, REM; Young Adult
PubMed: 35546027
DOI: 10.23750/abm.v93i2.11218