Rapid eye movement (REM) sleep is a unique brain state crucial for emotion, memory, and plasticity. Unlike well-understood non-REM (NREM) sleep homeostasis, REM sleep homeostasis remains less clearly defined. This review highlights recent progress in understanding REM sleep homeostasis, focusing on its neurophysiological markers, neural circuits, and significance for disease development. We start by outlining key theoretical models of REM sleep pressure, rebound, and gating and analyzing electrophysiological markers such as PGO wave density, hippocampal theta oscillations, and the pattern of REM sleep episodes. Then, we explore the hierarchical organization of REM-regulating networks, including brainstem cholinergic-GABAergic loops, hypothalamic centers, and limbic-cortical circuits, that reflect REM sleep pressure and influence its behavioral effects. Importantly, we discuss how disruptions in REM sleep homeostasis may contribute to the pathophysiology of major depressive disorder, post-traumatic stress disorder, and Parkinson's disease through changes in prefrontal-limbic connectivity, monoaminergic signaling, and REM sleep-dependent neuroplasticity. By linking circuit-level mechanisms with clinical implications, this review offers a comprehensive framework for understanding REM sleep homeostasis and guiding new therapies.
Insomnia, affecting millions worldwide, is a prevalent sleep disorder characterized by persistent difficulties in both initiating and maintaining sleep, leading to compromised daytime functioning, heightened risks of cardiovascular and psychiatric comorbidities, and substantial socioeconomic burdens necessitating the pursuit of safer and more efficacious therapeutic interventions. This review systematically evaluated research studies published between 2020 and 2024 on 71 natural product-based insomnia treatments—classified by chemical structure (terpenoids, flavonoids, and polyphenols)—and investigated their underlying GABAergic, serotonergic, and antioxidative mechanisms using both in vivo and in vitro evidence to elucidate potential multi-target benefits. In sum, although natural products represent a promising avenue for safer multi-faceted insomnia management, additional rigorous clinical studies and integrative methodologies are critical to establish efficacy, delineate molecular mechanisms, and advance these agents toward more precise and sustainable therapeutic applications.
Introduction: Obstructive sleep apnea syndrome (OSAS) is an inflammatory disease characterized by recurrent apnea and hypopnea. Multidrug resistance protein 1 (MRP1) is an anti-inflammatory protein that protects the cell from agents caused by oxidative stress. The aim of this study was to investigate the role of MRP1 in platelet function in OSAS.
Methods: According to the polysomnography results, 14 patients with simple snoring, 16 with mild OSAS, 14 with moderate OSAS, and 15 with severe OSAS were included in the study. Platelet aggregations were evaluated by an aggregometer. MRP1, CD62P (P-selectin), CD41b, and CD42b expressions were measured by a flow cytometer.
Results: Platelet aggregation levels were higher in the severe OSAS group than in the simple, mild, and moderate OSAS groups (p = 0.041). On the other hand, CD42b+/MRP1+ expression was lower in the severe OSAS group than in the simple, mild, and moderate OSAS groups (p = 0.002). MRP1 and CD42b expressions were consistent with this result (p = 0.013, p = 0.009, respectively). A positive correlation was found between apnea/hypopnea index and platelet aggregation (r = 0.289 p = 0.028) and a negative correlation was found between CD42b, CD42b+/MRP1+ (r = -0.419 p = 0.001, r = -0.357 p = 0.006, respectively).
Conclusion: Our findings suggest that high platelet activity and low MRP1 expression contribute to inflammation in OSAS and thus may be biomarkers.
Background: Sleep disturbances are often observed in people with alcohol-related cognitive disorders. In addition to their cognitive disorders, illness insight may be compromised in these patients, complicating addiction treatment adherence. Aim of this study was to examine the relationship between illness insight and subjective sleep disturbances in individuals with alcohol use disorder (AUD) without cognitive impairment, individuals with alcohol-related cognitive impairments (ARCI) and people with Korsakoff’s syndrome (KS) in a convenience sample. In addition, this study examines the role of illness insight in dysfunctional beliefs and attitudes about sleep.
Methods: Twenty-four individuals with KS, 17 individuals with ARCI and 21 individuals with AUD participated in this study. Illness insight was measured using the Q8 questionnaire. Subjective sleep disturbances were measured using the Pittsburg Sleep Quality Index and the Dysfunctional Beliefs and Attitudes about Sleep questionnaire. General cognitive functioning was assessed with the Montreal Cognitive Assessment.
Results: Comparable levels of subjective sleep disturbances across the three diagnostic groups were found. Also, no significant relation was found between subjective sleep disturbances and illness insight in the three groups.
Conclusion: This study suggests that the level of illness insight does not appear to play a role in the self-report of sleep disturbances.
Background: Non-suicidal self-injury (NSSI), suicidal ideation (SI), and suicide attempts (SA) are major concerns among college students. Sleep may be a modifiable factor, but its associations with NSSI, SI, and SA remain unclear.
Methods: A cross-sectional survey of 10,498 college students using a self-report questionnaire. Sleep health indicators include insomnia symptoms, duration, chronotype, snoring, and daytime sleepiness. Multivariable logistic regression models and restricted cubic spline analyses were used to examine associations between sleep patterns and self-injurious behaviors.
Results: The prevalence of NSSI, SI, and SA was 4.8%, 29.7%, and 3.7%, respectively. Participants with higher healthy sleep scores exhibited significantly reduced risks of NSSI, SI, and SA, with dose-response relationships observed. Each one-point increase in the sleep score was associated with a 43% lower risk of NSSI (odds ratios (OR) = 0.57, 95% CI: 0.52-0.62), a 37% lower risk of SI (OR = 0.63, 95% CI: 0.61-0.66), and a 48% lower risk of SA (OR = 0.52, 95% CI: 0.48-0.58).
Conclusion: Healthy sleep patterns were significantly associated with reduced risks of NSSI, SI, and SA among Chinese college students. These findings underscore the importance of promoting comprehensive sleep health as a public health strategy to mitigate self-injurious behaviors in young populations.