The Effects of Sleep Quality on Dream and Waking Emotions

Evidence of an active role of dreaming in emotional memory processing shows that we dream to forget

Dreaming is a universal human behavior that has inspired searches for meaning across many disciplines including art, psychology, religion, and politics, yet its function remains poorly understood. Given the suggested role of sleep in emotional memory processing, we investigated whether reported overnight dreaming and dream content are associated with sleep-dependent changes in emotional memory and reactivity, and whether dreaming plays an active or passive role. Participants completed an emotional picture task before and after a full night of sleep and they recorded the presence and content of their dreams upon waking in the morning. The results replicated the emotional memory trade-off (negative images maintained at the cost of neutral memories), but only in those who reported dreaming (Dream-Recallers), and not in Non-Dream-Recallers. Results also replicated sleep-dependent reductions in emotional reactivity, but only in Dream-Recallers, not in Non-Dream-Recallers. Additionally, the more positive the dream report, the more positive the next-day emotional reactivity is compared to the night before. These findings implicate an active role for dreaming in overnight emotional memory processing and suggest a mechanistic framework whereby dreaming may enhance salient emotional experiences via the forgetting of less relevant information.

Dissociated profiles of sleep timing and sleep quality changes across the first and second wave of the COVID-19 pandemic

Previous work showed a significant impact of the COVID-19 pandemic on Italians' sleep both during the first wave, when a total lockdown (TL) was imposed, and during the second wave, when a partial lockdown (PL) was mandated (autumn 2020). Here we complement these data by describing the profile of sleep across four time-points: the first and second lockdown (TL, PL) and the months preceding them (pre-TL, pre-PL). An online survey was completed by 214 participants (M_age = 36.78 ± 14.2 y; 159 F) during TL and again during PL. All sleep-related questions (including items of the Pittsburgh Sleep Quality Index) required a double answer, one referred to the current lockdown and one to the month preceding the lockdown. Bedtime and rise time were delayed in TL and then advanced in pre-PL and PL. Similarly, time in bed increased in TL and then decreased in pre-PL and PL. Sleep quality worsened in the two lockdowns compared to the preceding periods and the proportion of poor sleepers correspondingly increased in both lockdowns. Sleep habits and quality displayed different profiles across phases of the pandemic. Sleep timing was altered during the first lockdown and then returned towards baseline (likely due to normalized working schedules). Instead, sleep quality, which markedly worsened during both lockdowns, appears particularly sensitive to changes in life habits and psychological factors, independently of sleep habits. Our findings also point to a possible role of acute and chronic stress (experienced during the first and second wave, respectively) in modulating sleep changes across the pandemic waves.

Dreams and Nightmares during the First and Second Wave of the COVID-19 Infection: A Longitudinal Study

Recent literature shows that the Coronovirus-19 (COVID-19) pandemic has provoked significant changes in dreaming. The current study intends to provide an update about dream variable changes during the second wave of COVID-19. A total of 611 participants completed a web survey from December 2020 to January 2021. Statistical comparisons showed that subjects had lower dream-recall frequency, nightmare frequency, lucid-dream frequency, emotional intensity, and nightmare distress during the second than the first wave of the pandemic. Dreams had a higher negative tone during the second than first wave. We revealed significant differences concerning post-traumatic growth, sleep-related post-traumatic stress disorder (PTSD) symptoms and sleep measures between groups obtained as a function of the changes in the oneiric frequency between the first and second waves. We also found significant correlations between qualitative/emotional dream features and COVID-19-related factors (job change, forced quarantine, having COVID-19 infected relatives/friends, or asking for mental health help). Overall, we found that the second wave affected fewer quantitative features of dream activity and there was less emotional intensity. Moreover, we confirmed the relationship between nightmares and the high risk of PTSD when subjects were grouped as a function of the increasing/decreasing frequency. Finally, our findings are partly coherent with the continuity hypothesis between oneiric and waking experiences.

Dream Recall/Affect and the Hypothalamic-Pituitary-Adrenal Axis

In this concise review, we present an overview of research on dream recall/affect and of the hypothalamic–pituitary–adrenal (HPA) axis, discussing caveats regarding the action of hormones of the HPA axis (mainly cortisol and its free form, cortisol-binding globulin and glucocorticoid receptors). We present results of studies regarding dream recall/affect and the HPA axis under physiological (such as waking) or pathological conditions (such as in Cushing’s syndrome or stressful situations). Finally, we try to integrate the effect of the current COVID-19 situation with dream recall/affect vis-à-vis the HPA axis.

Changes in dream features across the first and second waves of the Covid-19 pandemic

Research during the Covid‐19 pandemic has highlighted its significant impact on dreaming. Here we address changes in dream features both during the first wave, when the Italian government imposed a total lockdown, and the second wave (autumn 2020), when a partial lockdown was effected. In April 2020 (total lockdown), 1,622 participants (M_age = 34.1 ± 13.6 years; 1171F) completed an online survey including the Pittsburgh Sleep Quality Index and a set of questions on dream features and their possible changes relative to the month preceding the lockdown (pre‐total lockdown). In November 2020 (partial lockdown), 214 participants (M_age = 36.78 ± 14.2 years; 159F) from the previous sample completed the same survey. Approximately half of the subjects reported increased or decreased dream frequency (30.5% and 21.8%), length (27.1% and 15.8%) and vividness (31.5% and 17.1%) during total lockdown as well as during partial lockdown (frequency: 30.3% and 13.5%; length: 23.3% and 12.6%; vividness: 31.6% and 24.1%). Dream affect became significantly more negative in total lockdown relative to pre‐total lockdown and in partial lockdown relative to pre‐partial lockdown (both p < .001). Both in total lockdown and partial lockdown, increased negative dream emotionality significantly predicted changes in dream frequency, length and vividness, and was significantly predicted, in turn, by worsened sleep quality. Our data confirm that dream features are significantly affected by major life changes such as those imposed by a pandemic. The fact that between lockdowns negative dream affect returned almost to baseline level suggests that dream emotionality is closely related to lifestyle and wake‐time emotional changes. Also, our findings point to a modulating role of sleep quality on dream emotionality.