Sleep
May 1, 2025
Michael J. Thorpy, Jennifer M Mundt, Sally Ibrahim et al.
In people with narcolepsy type 1, once-nightly sodium oxybate reduced the number of hypnagogic/hypnopompic hallucinations (HH) per day compared with placebo over 13 weeks. At baseline, participants averaged about 0.6 HH events per day. By week 13, the sodium oxybate group showed a mean reduction of 0.29 events per day, while the placebo group showed a reduction of 0.24 events per day. Among 12,455 total HH events, 62% were hypnagogic (occurring at sleep onset) and 38% were hypnopompic (occurring upon waking). The most common hallucination types were feeling that shadows or objects are moving or distorting and feeling another presence in the room. Approximately half as many events of feeling attacked, flying, or falling into a hole were reported with sodium oxybate versus placebo.
Sleep
May 1, 2025
Denise C. Vidot, Amrit Baral, Bria-Necole Diggs et al.
Among 18-to-35-year-olds in the Herbal Heart Study, 39.5% reported lifetime psychedelic use and 32.8% reported psilocybin use. Overall, 54.5% were satisfied with sleep, 23.0% dissatisfied, and 22.5% neutral, with no differences in sleep satisfaction across the full sample. However, among Hispanic/Latino participants, 33.9% of psychedelic consumers reported sleep dissatisfaction versus 17.2% of non-consumers. Hispanic/Latino psychedelic consumers had 4.4 times higher odds of both sleep dissatisfaction and satisfaction compared to being neutral; psilocybin-alone consumers had 9.2 times higher odds of dissatisfaction. No associations appeared among non-Hispanic White, non-Hispanic Black, or other groups, suggesting a complex link specific to Hispanic/Latino individuals.
Sleep
May 1, 2025
April Roper, Chase A. Stratton, Janeese Brownlow
People who have used psychedelic drugs at any point show small differences in objective sleep patterns measured by Fitbit devices compared with non-users. Users averaged 406 minutes in bed and non-users 405 minutes. Psychedelic use predicted more total sleep time, less REM sleep, more light sleep, and more deep sleep, but the effect sizes were negligible. The study analyzed data from 21,076 adults in the All of Us research database, of whom 7,799 reported psychedelic use and 13,277 did not. The findings suggest that while statistically significant differences exist, their practical importance is minimal.
Sleep
April 20, 2024
Garrett Baber, Daiil Jun, Jeffrey M. Girard et al.
Fearful dreams are associated with worse mood the following day, not better. Analyzing 4986 daily reports from 553 participants, the study found that on days when a person's dream contained more fear, their next-day negative affect was 14% higher—more than twice the effect of poor sleep efficiency (6%). People who generally had more fearful dreams also reported 12% higher average negative affect. These results contradict the theory that dreaming about fear helps regulate mood through a process similar to desensitization therapy. Instead, fearful dreams appear to be a meaningful day-to-day predictor of lower mood, independent of sleep quality and personality traits like neuroticism.
Sleep
May 1, 2021
Tommy Begay, Dora Valencia, Sadia Ghani et al.
Among 155 predominantly Hispanic/Latino adults near the US-Mexico border, people who experienced more pandemic-related stress reported more nightmares, even after accounting for depression and anxiety symptoms. Those with higher stress were also more likely to have nightmares about confinement, suffocation, failure, being chased, sickness, and COVID itself. The findings suggest that reducing pandemic-related stress might lessen nightmares and potentially improve mental health.
Sleep
May 19, 2025
Emily Feldman, Rebecca Essien, Danya Husein et al.
Childhood nightmares predict more frequent dream recall and dream sharing, but current psychological factors and attitudes toward dreams are stronger predictors. Among 360 undergraduates, childhood nightmares were linked to higher dream recall and more sharing. Current psychological distress predicted lower dream recall, while PTSD symptoms and distress were associated with less dream sharing. Insomnia severity, more dream sharing, perceived caregiver warmth, and fewer sleep-related phenomena were linked to increased dream recall. Negative dream attitudes, fewer sleep-related phenomena, and more déjà vu experiences predicted greater dream sharing. The findings indicate that early sleep experiences, mental health, and dream-related attitudes interact to shape dream recall and sharing patterns.
Sleep
May 19, 2025
Garrett Baber, Nancy Hamilton, Matthew Gratton
ChatGPT's ratings of positive and negative affect in dream reports showed excellent agreement with participants' own ratings. In 136 dream reports, the model's positive affect ratings matched self-reports with an intra-class correlation coefficient of 0.844 and a mean absolute error of 1.778 on a 0–10 scale. For negative affect, agreement was similarly high, with an ICC of 0.857 and a mean absolute error of 1.681. Bland-Altman plots revealed no systematic bias. The findings suggest that large language models can reliably estimate emotional content in dream narratives, offering a scalable alternative to self-report for sleep and affective research.
Sleep
May 19, 2025
Otis Eads, John Richmond Sy, Ruth Brombach et al.
People who believe that external forces control their lives (external locus of control) report having lucid dreams more often, but only if they already identify as lucid dreamers. Among 348 young adults surveyed, those who identified as lucid dreamers experienced lucid dreams about once a month, whereas non-lucid dreamers had them less than once a year. The relationship between external locus of control and lucid dreaming frequency was significant only for self-identified lucid dreamers. The authors suggest that individuals who feel a lack of control during the day may use lucid dreaming to regain a sense of agency.
Sleep
May 1, 2025
W. Youngren, Emma Angle, Victoria West Staples et al.
Dream-related self-efficacy (DSE) increased after a single session of Targeted Dream Incubation (TDI), a protocol that cues dream reports during hypnagogic sleep and then asks participants to think of a tree. Higher DSE at all time points was significantly negatively correlated with suicidal cognitions one week later, and the increase in DSE from baseline to follow-up significantly predicted lower suicidal cognitions. These results suggest that DSE may be a mechanism through which TDI reduces suicidal thinking, though the small sample of fifteen participants limits generalizability.
Sleep
May 1, 2025
Lefulesele Kholoane, Roberta Jacobs, Nichole Mogharreban et al.
A quality improvement project at a Veterans Affairs sleep clinic evaluated whether a group format for narrative-enhanced imagery rehearsal therapy (N-IRT) could improve access to nightmare treatment for US Veterans. After revising triage workflows and eligibility criteria, wait times for individual sleep psychologist appointments dropped from 79.3 days in January 2024 to 28.9 days by March 2024. However, group utilization remained low: between September and October 2024, only 4 of 20 referred patients attended group N-IRT. Barriers included scheduling conflicts, medical complexity, and patient preference for individual care. The authors argue that multiple interventions and patient and provider education are needed to overcome these barriers.
Sleep
December 1, 2024
Sentiment analysis tools vary in their ability to estimate affective valence in dream reports. Comparing several tools, the study finds that different methods yield divergent results, suggesting that the choice of tool significantly influences the measurement of emotional tone in dream narratives. The authors recommend careful selection of sentiment analysis approaches for dream research.
Sleep
April 20, 2024
Arezou Heshmati
A 15-year-old boy with recurrent isolated sleep paralysis underwent overnight polysomnography and a multiple sleep latency test. During the test, an episode of sleep paralysis lasting approximately 48 seconds was captured on EEG. The recording showed a mixture of rapid eye movement (REM) sleep features—such as muscle atonia and theta waves—alongside faster frequencies and alpha waves typical of relaxed wakefulness. This overlap of REM and wakeful brainwave patterns illustrates the mixed state of consciousness during sleep paralysis, contributing to understanding its neurophysiological basis.
Sleep
April 20, 2024
Chadwick C Frost, Taya Middleton, Erin J. Wamsley
Recalling a personal emotional memory before sleep did not make people dream about that memory more than writing about a neutral topic. However, dreams after recalling an angry memory were rated as more negative in emotion, especially the first dream reported. This suggests that while pre-sleep experiences rarely appear directly in dream content, emotional stimuli can influence the emotional tone of dreams, possibly reflecting emotional memory consolidation or a general effect of pre-sleep mood on dream emotion.
Sleep
April 20, 2024
Shalini Gupta, A. Avidan
A 74-year-old man with REM sleep behavior disorder, visual hallucinations, and new cognitive deficits perceived the world as a persistent dream-like state for two years, describing objects as unreal, cartoon-like, and distorted. Polysomnography confirmed REM sleep without atonia. The authors argue that people with dementia with Lewy bodies experience a spectrum of sleep disorders and complex visual hallucinations reflecting impaired sensory integration during the transition from mild cognitive impairment to dementia. They contend that sleep clinicians must recognize visual-spatial processing disorders in any patient presenting with sleep-related hallucination, as these may be stigmatized or misattributed to REM sleep behavior disorder.
Sleep
April 20, 2024
Michael Spano, Edward F Pace-Schott
Sleep paralysis (SP) frequency among university students is linked to napping and alcohol use. In a survey of 158 students, those who experienced SP daily napped 4–7 times per week, while those who experienced SP once napped only 1–3 times per month. Most non-SP experiencers napped rarely or never. Daily SP experiencers also reported drinking alcohol more often than one-time experiencers. No differences were found for caffeine or nicotine use. The direction of causation between frequent napping and SP remains unknown. The study suggests drinking frequency may moderately predict SP, and more research is needed on phone and social media use.
Sleep
April 1, 2024
The study investigates whether prolonged sleep onset latency serves as a proxy for fear-of-sleep-related arousal in individuals with nightmares. Findings suggest that extended time to fall asleep may reflect heightened arousal linked to fear of sleep, rather than simply indicating general sleep disturbance. The research highlights the importance of considering fear-of-sleep-related arousal when assessing objective sleep disturbances in nightmare sufferers.
Sleep
February 1, 2024
C. Paquet, K. Lenker, S. Calhoun et al.
Sleep continuity—particularly the ability to fall asleep and maintain sleep—is more unstable in people who have both nightmares and insomnia than in those with chronic insomnia alone or good sleepers. Over four nights in a sleep lab, the comorbid group showed poor stability in wake after sleep onset and stage 1 sleep, took longer to fall asleep, and had a greater first-night effect in stage 1. Both the comorbid and insomnia-alone groups slept less overall but had fewer awakenings and REM periods than good sleepers. The authors suggest that pre-sleep anxiety and nightmare-related distress may drive these differences.
Sleep
December 11, 2023
Lauren Hudachek, Erin J. Wamsley
Dreaming about newly learned information is strongly associated with better memory after sleep, according to a meta-analysis of 16 studies. Across 45 reported effects, the association between task-related dreaming and memory performance was statistically significant. The relationship held for all types of learning tasks examined. Among studies using polysomnography, the association was significant for dreams collected during non-rapid eye movement (NREM) sleep but not for those from rapid eye movement (REM) sleep. These results suggest that dream content may reflect memory consolidation, with preliminary evidence that the link between dreaming and memory may be stronger in NREM sleep than in REM sleep.
Sleep
May 29, 2023
Stephanie Hart, Lauren Tobias
Hypnagogic hallucinations—vivid, dream-like experiences that occur while falling asleep—can be a symptom of Parkinson's disease (PD) even in patients who do not have narcolepsy. A 66-year-old woman with tremor and dream enactment reported seeing a grim reaper and a dark figure upon falling asleep. She was diagnosed with mild obstructive sleep apnea and loss of REM atonia. Treatment with melatonin and clonazepam improved dream enactment. Over two years, she was diagnosed with PD and started on carbidopa-levodopa; higher doses of dopaminergic therapy were associated with more frequent hypnagogic hallucinations. The case illustrates that such hallucinations are not exclusive to narcolepsy and may be underrecognized in PD.
Sleep
April 12, 2023
Claudia Picard-Deland, Karen R Konkoly, Rachel Raider et al.
Dreams incorporate memories from waking life, but this incorporation varies across the night. Twenty healthy adults were awakened repeatedly during early, middle, and late sleep stages (N1, N2, N3, REM) to collect dream reports. Recent memories appeared more often in N1 and REM dreams than in other stages. Distant memories from over a week ago, semantic memories, and anticipated future events remained stable across sleep stages. However, across the night, the balance shifted: late-night dreams in all stages contained fewer recent and more remote memories than earlier dreams. Dreams also repeated similar themes across the night. These results suggest that dream content may reflect sleep-dependent memory consolidation processes.
Sleep
May 25, 2022
Maurice Ohayon, Amir Pakpour, Marie Lise Cote
About 11.7% of the general population reported hypnagogic hallucinations in the previous year, and three years later 9.3% reported them. Among those who had hallucinations at the first interview, 22.8% still had them at the second, representing 2.1% of the total sample. The three-year incidence was 5.7%. Persistent hypnagogic hallucinations were predicted by persistent pain, persistent hypersomnolence, persistent sleep paralysis, and persistent cataplexy-like symptoms. Chronicity is most strongly associated with narcolepsy-related factors.
Sleep
November 12, 2021
Monika Kliková, Marek Piorecký, Eva Miletínová et al.
Recurrent isolated sleep paralysis (RISP) involves a dissociative state mixing REM sleep and wakefulness, but its causes are unclear. In a study comparing 19 people with RISP to 19 matched controls, no differences were found in REM sleep macrostructure (percentage of REM sleep and REM latency) or in REM sleep fragmentation (measured by arousal index, wakefulness, and stage shifts). However, power spectral analysis revealed higher bifrontal beta activity during REM sleep in the RISP group. This suggests a persistent trait of elevated cortical activity that may predispose individuals to recurrent episodes, without signs of greater REM sleep fragmentation.
Sleep
May 3, 2021
Chloe Wills, Kathryn Kennedy, Célyne Bastien et al.
During the COVID-19 pandemic, a survey of 419 US adults examined links between sleep, stress, and dream recall. People whose sleep worsened were more likely to report both increased and decreased dream recall. Those with greater schedule regularity or sleep improvement were less likely to report decreased recall. Negative dream content, positive dream content, maintenance insomnia, and daytime sleepiness were all associated with both increased and decreased recall. Decreased recall was linked to greater insomnia severity, fatigue, sleepiness, COVID stress, anxiety, depression, worse sleep environment, and less sleep control. The authors suggest a sudden drop in dream recall in response to new stress may indicate poor sleep quality and mental health.
Sleep
December 14, 2020
Raphael Vallat, Alain Nicolas, Perrine Ruby
People who frequently recall dreams show distinct brain connectivity patterns immediately after waking compared to those who rarely recall dreams. The study measured brain functional connectivity using combined EEG-fMRI in 20 high dream recallers and 18 low dream recallers before and after an early-afternoon nap. Five minutes after awakening, high recallers exhibited enhanced connectivity within the default mode network and between the default mode network and memory-related brain regions. This connectivity pattern may help maintain the short-term memory of dreams during the transition from sleep to wakefulness. The groups differed in dream recall but not in recall of a comic presented before the nap.
Sleep
November 27, 2020
Jessica R. Dietch, Daniel J. Taylor, K. Pruiksma et al.
About 7.4% of nurses met full criteria for probable nightmare disorder, and 43.9% had partial or subthreshold symptoms, based on a new self-report measure called the Nightmare Disorder Index (NDI). The NDI showed good reliability and validity. Nurses with nightmare disorder had significantly worse psychosocial functioning—including higher posttraumatic stress, depression, anxiety, and stress—than those with subthreshold symptoms, who in turn had poorer functioning than nurses with no nightmares. The findings suggest that nightmares are common among nurses and are linked to poorer mental health, supporting increased screening in high-risk healthcare workers.