Clocks & Sleep
September 19, 2021
Valentina Elce, Giacomo Handjaras, Giulio Bernardi
29 citations
Dream reports—oral or written accounts given upon awakening—are a key source of insight into dreaming. Traditionally, structural information (e.g., word or sentence counts) and semantic content (scored by human coders using predefined systems) are extracted from these reports. This review argues that linguistic analysis methods—graph analysis, dictionary-based content analysis, and distributional semantics—can complement or replace classical measures. These techniques allow direct, operator-independent extraction of quantitative information, enabling fully objective and reproducible analysis of conscious experiences during sleep. They can be partially or fully automated, making them suitable for large datasets.
Clocks & Sleep
March 1, 2020
Michael Schredl, Sophie Dyck, Anja Kühnel
22 citations
Lucid dreaming does not impair the feeling of being refreshed in the morning. In a five-week dream diary study with 149 participants, nights with a lucid dream were followed by a higher feeling of being refreshed compared to nights with a non-lucid dream. Earlier cross-sectional studies had linked frequent lucid dreaming to poorer sleep quality, but that relationship was explained by nightmare frequency, not lucid dreaming itself. The findings indicate no negative effect of lucid dreaming on sleep's restorative function, though future research should use both objective and subjective measures of daytime tiredness.
Clocks & Sleep
May 30, 2023
Marco Fabbri
6 citations
During the first Italian COVID-19 lockdown, adults reported delayed sleep timing, a slowdown in the perception of the present time, decreased time pressure, and increased feelings of time expansion and boredom. A longitudinal study of 39 Italian adults found that changes in dispositional mindfulness predicted a delay in bedtime during workdays, mediated by an increased feeling of time expansion and boredom. This suggests mindfulness may help regulate sleep timing by reducing boredom-related time distortions.
Clocks & Sleep
April 20, 2022
Daniel Erlacher, Vitus Furrer, Matthias Ineichen et al.
3 citations
Lucid dreaming, where dreamers are aware they are dreaming and can communicate with researchers in real time, offers a new way to study dreams. However, such research is limited because lucid dreamers are rare. In three experiments replicating an earlier method that successfully induced lucid dreams in 50% of participants, the researchers shortened the first sleep period to 4.5 hours (instead of 6), simplified morning awakenings, and tested a different induction technique. Only 26%, 0%, and 20% of participants reported lucid dreams, suggesting that earlier sleep interruption reduces success, that REM awakenings are necessary for induction, and that reality testing is less effective than the mnemonic technique.
Clocks & Sleep
June 26, 2025
Y. Tanaka, Yuichiro Otsuka, Suguru Nakajima et al.
1 citation
Among Japanese high school students, the frequency of rumination at bedtime and unpleasant dreams is strongly associated with anxiety and depressive symptoms. Rumination at bedtime showed an adjusted odds ratio of 10.60 for anxiety symptoms and 8.79 for depressive symptoms; unpleasant dreams showed 5.25 for anxiety and 10.13 for depression. Other dream features such as memory of dreams, emotional carryover, and awakening by frightening, film-like, fantastical, or recurring dreams also correlated with higher symptom prevalence, but pleasant dreams did not. These findings suggest that bedtime rumination and unpleasant dreams may serve as early indicators of declining mental health in adolescents.
Clocks & Sleep
September 1, 2022
Michael Schredl, Claudia Schilling
Dysfunctional sleep-related metacognitions (thoughts about one's own thinking during sleep) are linked to more negatively toned dreams and nightmares, even after accounting for a person's general tendency to become aroused. In a study of 919 patients with sleep disorders, those who scored higher on a measure of sleep-related metacognitions reported more nightmares and more negative dream emotions. The effect of metacognitions was small, while the effect of trait arousability was medium. The findings suggest that metacognitive therapy, which targets these sleep-related thoughts, might also improve dream quality by reducing nightmares and increasing positive dream emotions.
Clocks & Sleep
February 28, 2022
Angelina Birchler-Pedross, Sylvia Frey, Christian Cajochen et al.
Women with major depressive disorder (MDD) recall dreams as often as healthy women, but their dreams carry twice the negative emotional load, especially during the circadian night. In a controlled laboratory protocol, nine healthy and eight unmedicated women with MDD underwent ten alternating cycles of 150 minutes awake and 75 minutes asleep over 40 hours. Dream recall frequency did not differ between groups, but dream emotional load was significantly higher in the MDD group during nighttime naps. Higher negative emotional load in dreams correlated with worse mood in both groups. The findings suggest that circadian and sleep regulation of dreaming remains intact in unmedicated young women with MDD.
Clocks & Sleep
January 29, 2022
Alexandros S Triantafyllou, Ioannis Ilias, Nicholas-Tiberio Economou et al.
Higher cortisol levels, measured in saliva, are linked to increased dream recall and more positive dream affect. In a sample of 15 men and 15 women, those with higher evening or morning cortisol tended to recall more dreams. A statistically significant association emerged for morning cortisol levels above 19.1 nmol/L, where the odds of recalling a dream with positive affect were over four times higher. No connection was found between menstrual cycle phase and dream recall or affect. Cortisol may be an important modulator of dreaming, warranting further research.
Clocks & Sleep
November 24, 2021
M. Schredl
Clocks appear in only 0.74% of a single male dreamer's series of 12,476 dreams, and clocks owned by the dreamer in waking life are especially rare in his dreams. The variety of contexts in clock dreams extends beyond the dreamer's time management. The low frequency may reflect novelty: regularly repeated waking-life experiences tend not to appear often in dreams. Studying everyday objects like clocks could refine models of waking-dreaming continuity.
Clocks & Sleep
July 22, 2021
Athanasios Tselebis, Emmanouil Zoumakis, Ioannis Ilias
This review examines the relationship between dream recall and affect and the hypothalamic-pituitary-adrenal (HPA) axis, focusing on cortisol, its free form, cortisol-binding globulin, and glucocorticoid receptors. It covers findings from studies under normal waking conditions and pathological states like Cushing's syndrome or stress. The review also attempts to integrate the impact of the COVID-19 pandemic on dream recall and affect in relation to the HPA axis.
Clocks & Sleep
September 1, 2020
Michael Schredl, Anja S. Göritz
Eveningness (being an 'owl') is linked to more frequent nightmares, but this relationship is mediated by neuroticism. Morningness (being a 'lark') is associated with higher dream recall than late bedtime preferences. Urbanicity—being raised in or currently living in an urban area—was not related to nightmare frequency but was linked to lower nightmare distress, suggesting that beliefs about nightmares may influence distress levels. These findings come from an online survey of 2,492 adults (mean age 47.75 years) and highlight unresolved questions about how nightmares, chronotype, and urbanicity interact.