Melatonin (MEL) and its use in neurological diseases and insomnia: Recommendations of the French Medical and Research Sleep Society (SFRMS)

Modulation of neural circuits by melatonin in neurodegenerative and neuropsychiatric disorders

Neurodegenerative and neuropsychiatric disorders are two broad categories of neurological disorders characterized by progressive impairments in movement and cognitive functions within the central and peripheral nervous systems, and have emerged as a significant cause of mortality. Oxidative stress, neuroinflammation, and neurotransmitter imbalances are recognized as prominent pathogenic factors contributing to cognitive deficits and neurobehavioral anomalies. Consequently, preventing neurodegenerative and neuropsychiatric diseases has surfaced as a pivotal challenge in contemporary public health. This review explores the investigation of neurodegenerative and neuropsychiatric disorders using both synthetic and natural bioactive compounds. A central focus lies on melatonin, a neuroregulatory hormone secreted by the pineal gland in response to light-dark cycles. Melatonin, an amphiphilic molecule, assumes multifaceted roles, including scavenging free radicals, modulating energy metabolism, and synchronizing circadian rhythms. Noteworthy for its robust antioxidant and antiapoptotic properties, melatonin exhibits diverse neuroprotective effects. The inherent attributes of melatonin position it as a potential key player in the pathophysiology of neurological disorders. Preclinical and clinical studies have demonstrated melatonin's efficacy in alleviating neuropathological symptoms across neurodegenerative and neuropsychiatric conditions (depression, schizophrenia, bipolar disorder, and autism spectrum disorder). The documented neuroprotective prowess of melatonin introduces novel therapeutic avenues for addressing neurodegenerative and psychiatric disorders. This comprehensive review encompasses many of melatonin's applications in treating diverse brain disorders. Despite the strides made, realizing melatonin's full neuroprotective potential necessitates further rigorous clinical investigations. By unravelling the extended neuroprotective benefits of melatonin, future studies promise to deepen our understanding and augment the therapeutic implications against neurological deficits.

Acupuncture for primary insomnia: Effectiveness, safety, mechanisms and recommendations for clinical practice

Primary insomnia (PI) is an increasing concern in modern society. Cognitive-behavioral therapy for insomnia is the first-line recommendation, yet limited availability and cost impede its widespread use. While hypnotics are frequently used, balancing their benefits against the risk of adverse events poses challenges. This review summarizes the clinical and preclinical evidence of acupuncture as a treatment for PI, discussing its potential mechanisms and role in reliving insomnia. Clinical trials show that acupuncture improves subjective sleep quality, fatigue, cognitive impairments, and emotional symptoms with minimal adverse events. It also positively impacts objective sleep processes, including prolonging total sleep time, improving sleep efficiency, reducing sleep onset latency and wake after sleep onset, and enhancing sleep architecture/structure, including increasing N3% and REM%, and decreasing N1%. However, methodological shortcomings in some trials diminish the overall quality of evidence. Animal studies suggest that acupuncture restores circadian rhythms in sleep-deprived rodents and improves their performance in behavioral tests, possibly mediated by various clinical variables and pathways. These may involve neurotransmitters, brain-derived neurotrophic factors, inflammatory cytokines, the hypothalamic-pituitary-adrenal axis, gut microbiota, and other cellular events. While the existing findings support acupuncture as a promising therapeutic strategy for PI, additional high-quality trials are required to validate its benefits.

Melatonin secretion and sleep disorders in patients with spinal cord injuries

STUDY DESIGN

Prospective observational study.

OBJECTIVES

To evaluate melatonin secretion, daytime sleepiness and sleep disorders in patients with spinal cord injuries (SCI), and their association with lesion level.

SETTING

Specialized neuro rehabilitation hospital in France METHODS: Prospective observational study of patients aged over 18 hospitalized in for spinal cord injury. Sleep quality was measured with the Pittsburgh Sleep Quality Index (PQSI), daytime sleepiness with the Epworth Sleepiness scale (ESS), and melatonin secretion by 24 h urinary dosage of 6-sulphatoxy-melatonin.

RESULTS

213 patients were screened, 21 patients were included: 17 complete (AIS A) and 4 lesions (AIS B), 76% of traumatic origin with 12 tetraplegic and 9 paraplegic, mean 10 (range 0.5-40) years after injury. Mean age was 46.8 ± 14.7 years, mean BMI 23.56 ± 4.1 and men outnumbered women (15 vs 6). Melatonin secretion was analyzed by 24 h secretion and by secretion profile. Comparing retained vs abolished secretion, only 23% (4/17) of patients with a lesion above T8 retained melatonin secretion, compared to 80% (4/5) with a lesion below T8 (p = 0.022). Non significant differences were found in secretion profile in patients who retained secretion: no patient with a lesion above T8 had a normal secretion profile compared to 50% with a lesion below T8 and in the impact of partial vs total lesions above T8 in whom 17% (2/12) of complete ASIA-A lesions and 50% (2/4) of incomplete lesions retained secretion.

CONCLUSION

Lesions of the spinal cord above T8 are strongly associated with abolition of melatonin secretion.

Circadian Rhythm Changes in Healthy Aging and Mild Cognitive Impairment

Disruptions in circadian rhythms can occur in healthy aging; however, these changes are more severe and pervasive in individuals with age-related and neurodegenerative diseases, such as dementia. Circadian rhythm alterations are also present in preclinical stages of dementia, for example, in patients with mild cognitive impairments (MCI); thus, providing a unique window of opportunity for early intervention in neurodegenerative disorders. Nonetheless, there is a lack of studies examining the association between relevant changes in circadian rhythms and their relationship with cognitive dysfunctions in MCI individuals. In this review, circadian system alterations occurring in MCI patients are examined compared to healthy aging individuals while also considering their association with MCI neurocognitive alterations. The main findings are that abnormal circadian changes in rest-activity, core body temperature, melatonin, and cortisol rhythms appear in the MCI stage and that these circadian rhythm disruptions are associated with some of the neurocognitive deficits observed in MCI patients. In addition, preliminary evidence indicates that interventions aimed at restoring regular circadian rhythms may prevent or halt the progress of neurodegenerative diseases and mitigate their related cognitive impairments. Future longitudinal studies with repeated follow-up assessments are needed to establish the translational potential of these findings in clinical practice.

Effect of melatonin on sleep quality and EEG features in childhood epilepsy: a possible non-conventional treatment

Background

Sleep and epilepsy are characterized by a bidirectional relationship. Indeed, epilepsy predisposes to the development of sleep disorders, while sleep deprivation may exacerbate epilepsy. In addition, antiseizure medication can disrupt normal sleep architecture. Therefore, adequate sleep hygiene could lead to improvement in seizure control. The present study aimed to evaluate the effect of melatonin on seizure frequency, EEG tracing, and sleep in children with focal idiopathic epilepsy.

Methods

This observation study evaluated the effect of 4 mg oral melatonin in ameliorating sleep-wake cycle, seizure frequency, and EEG features in children with focal idiopathic epilepsy of infancy. Twenty children were enrolled from September 2020 to August 2021. The study consisted of serial controls at enrollment (t0), at 3 months (t1), and at 6 months (t2) including neurological examination, questionnaire about sleep disturbances (CSHQ), and EEG.

Results

A significant improvement in sleep quality and daytime sleepiness was observed after melatonin supplementation. Furthermore, we observed a noteworthy improvement in EEG tracing at t2 that exhibited a significant correlation with improvements in CSHQ scores.

Conclusion

The studies conducted so far to evaluate the effect of melatonin in persons with epilepsy do not lead to definitive conclusions. Despite the small population sample and the study design, we report sleep and EEG improvement after melatonin administration in our cohort. Larger studies are needed to further study the neuroprotective and anticonvulsant properties of melatonin.

An Exploratory Study of Sleep-Wake Differences of Autonomic Activity in Patients with Mild Cognitive Impairment: The Role of Melatonin as a Modulating Factor

Purpose

The objective of the present study was to assess sleep-wake differences of autonomic activity in patients with mild cognitive impairment (MCI) compared to control subjects. As a post-hoc objective, we sought to evaluate the mediating effect of melatonin on this association.

Patients and Methods

A total of 22 MCI patients (13 under melatonin treatment) and 12 control subjects were included in this study. Sleep-wake periods were identified by actigraphy and 24hr-heart rate variability measures were obtained to study sleep-wake autonomic activity.

Results

MCI patients did not show any significant differences in sleep-wake autonomic activity when compared to control subjects. Post-hoc analyses revealed that MCI patients not taking melatonin displayed lower parasympathetic sleep-wake amplitude than controls not taking melatonin (RMSSD -7 ± 1 vs 4 ± 4, p = 0.004). In addition, we observed that melatonin treatment was associated with greater parasympathetic activity during sleep (VLF 15.5 ± 0.1 vs 15.1 ± 0.1, p = 0.010) and in sleep-wake differences in MCI patients (VLF 0.5 ± 0.1 vs 0.2 ± 0.0, p = 0.004).

Conclusion

These preliminary findings hint at a possible sleep-related parasympathetic vulnerability in patients at prodromal stages of dementia as well as a potential protective effect of exogenous melatonin in this population.

Melatonin as a Harmonizing Factor of Circadian Rhythms, Neuronal Cell Cycle and Neurogenesis: Additional Arguments for Its Therapeutic Use in Alzheimer's Disease

The synthesis and release of melatonin in the brain harmonize various physiological functions. The apparent decline in melatonin levels with advanced aging is an aperture to the neurodegenerative processes. It has been indicated that down regulation of melatonin leads to alterations of circadian rhythm components, which further causes a desynchronization of several genes and results in an increased susceptibility to develop neurodegenerative diseases. Additionally, as circadian rhythms and memory are intertwined, such rhythmic disturbances influence memory formation and recall. Besides, cell cycle events exhibit a remarkable oscillatory system, which is downstream of the circadian phenomena. The linkage between the molecular machinery of the cell cycle and complex fundamental regulatory proteins emphasizes the conjectural regulatory role of cell cycle components in neurodegenerative disorders such as Alzheimer's disease. Among the mechanisms intervening long before the signs of the disease appear, the disturbances of the circadian cycle, as well as the alteration of the machinery of the cell cycle and impaired neurogenesis, must hold our interest. Therefore, in the present review, we propose to discuss the underlying mechanisms of action of melatonin in regulating the circadian rhythm, cell cycle components and adult neurogenesis in the context of AD pathogenesis with the view that it might further assist to identify new therapeutic targets.

Possible Application of Melatonin in Long COVID

Clinical sequelae and symptoms for a considerable number of COVID-19 patients can linger for months beyond the acute stage of SARS-CoV-2 infection, "long COVID". Among the long-term consequences of SARS-CoV-2 infection, cognitive issues (especially memory loss or "brain fog"), chronic fatigue, myalgia, and muscular weakness resembling myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are of importance. Melatonin may be particularly effective at reducing the signs and symptoms of SARS-CoV-2 infection due to its functions as an antioxidant, anti-inflammatory, and immuno-modulatory agent. Melatonin is also a chronobiotic medication effective in treating delirium and restoring the circadian imbalance seen in COVID patients in the intensive care unit. Additionally, as a cytoprotector, melatonin aids in the prevention of several COVID-19 comorbidities, including diabetes, metabolic syndrome, and ischemic and non-ischemic cardiovascular diseases. This narrative review discusses the application of melatonin as a neuroprotective agent to control cognitive deterioration ("brain fog") and pain in the ME/CFS syndrome-like documented in long COVID. Further studies on the therapeutic use of melatonin in the neurological sequelae of SARS-CoV-2 infection are warranted.

Response to Treatment with Melatonin and Clonazepam versus Placebo in Patients with Burning Mouth Syndrome

Objective: to evaluate the efficacy of melatonin and clonazepam versus placebo in patients with burning mouth syndrome (BMS). Methods: a prospective double-blind study was carried out in patients with BMS and randomized to three groups: melatonin (1 mg once a day), clonazepam (0.5 mg/twice a day), or a placebo once a day, for 8 weeks. The clinical changes were evaluated, including xerostomia, the Oral Health Impact Profile 14 (OHIP-14) score, Pittsburg Sleep Quality Index, and the Hospital Anxiety and Depression Scale (HADS). Oxygen saturation and heart rate were recorded, with an analysis of salivary biomarkers in the forms of oxytocin, ferritin, adenosine deaminase (ADA), total proteins, and alpha-amylase. Results: a total of 64 patients were analyzed. A significant decrease in burning sensation was recorded with melatonin (7.8 ± 1.54 pre-treatment, 5.78 ± 2.54 post-treatment; p < 0.001) and clonazepam (8.75 ± 1.2 pre-treatment, 5.5 ± 3.6 post-treatment (p < 0.01). With regard to quality of life (OHIP-14), significant improvements were observed before and after the administration of melatonin (p < 0.001) and clonazepam (p = 0.001). On the other hand, with regard to the changes in salivary biomarkers following treatment, negative correlations were found between oxytocin and drainage (r = −0.410; p = 0.009) and between the HADS-D score and ferritin (r = −0.312; p = 0.05). While salivary amylase showed positive correlation with heart rate (r = 0.346; p = 0.029) and oxygen saturation (r = 0.419; p = 0.007). Conclusions: melatonin and clonazepam were shown to be effective at reducing the burning sensation and improving quality of life. Both drugs were found to be safe, with no major adverse effects in patients with BMS. Melatonin may be regarded as an alternative treatment for patients with BMS, though further studies are needed to confirm its effectiveness.

New uses of Melatonin as a Drug, a Review

Melatonin is a simple compound with a proper chemical name N-acetyl-5-methoxy tryptamine and known as a hormone controlling circadian rhythm. Humans produce melatonin at night which is the reason for sleeping in the night and awakening over the day. Melatonin interacts with melatonin receptors MT1 and MT2 but it was also revealed that melatonin is a strong antioxidant and it also has a role in regulation of cell cycle. Currently, melatonin is used as a drug for some types of sleep disorder but the recent research points to the fact that melatonin can also serve for the other purposes including prophylaxis or therapy of lifestyle diseases, cancer, neurodegenerative disorders and exposure to chemicals. This review summarizes basic facts and direction of the current research on melatonin. The actual literature was scrutinized for the purpose of this review.

Circadian rhythms in neurodegenerative disorders

Endogenous biological clocks, orchestrated by the suprachiasmatic nucleus, time the circadian rhythms that synchronize physiological and behavioural functions in humans. The circadian system influences most physiological processes, including sleep, alertness and cognitive performance. Disruption of circadian homeostasis has deleterious effects on human health. Neurodegenerative disorders involve a wide range of symptoms, many of which exhibit diurnal variations in frequency and intensity. These disorders also disrupt circadian homeostasis, which in turn has negative effects on symptoms and quality of life. Emerging evidence points to a bidirectional relationship between circadian homeostasis and neurodegeneration, suggesting that circadian function might have an important role in the progression of neurodegenerative disorders. Therefore, the circadian system has become an attractive target for research and clinical care innovations. Studying circadian disruption in neurodegenerative disorders could expand our understanding of the pathophysiology of neurodegeneration and facilitate the development of novel, circadian-based interventions for these disabling disorders. In this Review, we discuss the alterations to the circadian system that occur in movement (Parkinson disease and Huntington disease) and cognitive (Alzheimer disease and frontotemporal dementia) neurodegenerative disorders and provide directions for future investigations in this field.

Managing Sleep in Adults with ADHD: From Science to Pragmatic Approaches

BACKGROUND

Sleep disorders and sleep problems commonly occur in adults with ADHD and add to functional impairment. Evidence-based treatments for sleep could improve function in the adult ADHD population.

METHODS

A literature review was conducted to present the clinical science informing treatment of sleep in adults with ADHD.

RESULTS

Six systematic prospective studies of sleep intervention in adults with ADHD were identified. Three of these, all including well-characterized ADHD patients, offered evidence for a significant effect of morning light therapy. Across the studies, preliminary evidence for melatonin, behavioral therapy, and weighted blankets were also found.

IMPLICATION

Low-risk interventions such as light therapy may improve sleep in adults with ADHD, but many sleep interventions currently in use remain unstudied in the ADHD population. Considerations for evidence-informed practice and future research directions are discussed.

International Expert Opinions and Recommendations on the Use of Melatonin in the Treatment of Insomnia and Circadian Sleep Disturbances in Adult Neuropsychiatric Disorders

Introduction: Insomnia and circadian rhythm disorders, such as the delayed sleep phase syndrome, are frequent in psychiatric disorders and their evaluation and management in early stages should be a priority. The aim of this paper was to express recommendations on the use of exogenous melatonin, which exhibits both chronobiotic and sleep-promoting actions, for the treatment of these sleep disturbances in psychiatric disorders. Methods: To this aim, we conducted a systematic review according to PRISMA on the use of melatonin for the treatment of insomnia and circadian sleep disorders in neuropsychiatry. We expressed recommendations for the use of melatonin in psychiatric clinical practice for each disorder using the RAND/UCLA appropriateness method. Results: We selected 41 studies, which included mood disorders, schizophrenia, substance use disorders, attention deficit hyperactivity disorders, autism spectrum disorders, neurocognitive disorders, and delirium; no studies were found for both anxiety and eating disorders. Conclusion: The administration of prolonged release melatonin at 2-10 mg, 1-2 h before bedtime, might be used in the treatment of insomnia symptoms or comorbid insomnia in mood disorders, schizophrenia, in adults with autism spectrum disorders, neurocognitive disorders and during sedative-hypnotics discontinuation. Immediate release melatonin at <1 mg might be useful in the treatment of circadian sleep disturbances of neuropsychiatric disorders.

Melatonin as a Chronobiotic and Cytoprotective Agent in Parkinson's Disease

This article discusses the role that melatonin may have in the prevention and treatment of Parkinson’s disease (PD). In parkinsonian patients circulating melatonin levels are consistently disrupted and the potential therapeutic value of melatonin on sleep disorders in PD was examined in a limited number of clinical studies using 2–5 mg/day melatonin at bedtime. The low levels of melatonin MT1 and MT2 receptor density in substantia nigra and amygdala found in PD patients supported the hypothesis that the altered sleep/wake cycle seen in PD could be due to a disrupted melatonergic system. Motor symptomatology is seen in PD patients when about 75% of the dopaminergic cells in the substantia nigra pars compacta region degenerate. Nevertheless, symptoms like rapid eye movement (REM) sleep behavior disorder (RBD), hyposmia or depression may precede the onset of motor symptoms in PD for years and are index of worse prognosis. Indeed, RBD patients may evolve to an α-synucleinopathy within 10 years of RBD onset. Daily bedtime administration of 3–12 mg of melatonin has been demonstrated effective in RDB treatment and may halt neurodegeneration to PD. In studies on animal models of PD melatonin was effective to curtail symptomatology in doses that allometrically projected to humans were in the 40–100 mg/day range, rarely employed clinically. Therefore, double-blind, placebo-controlled clinical studies are urgently needed in this respect.

Is Melatonin the Cornucopia of the 21st Century?

Melatonin, an indoleamine hormone produced and secreted at night by pinealocytes and extra-pineal cells, plays an important role in timing circadian rhythms (24-h internal clock) and regulating the sleep/wake cycle in humans. However, in recent years melatonin has gained much attention mainly because of its demonstrated powerful lipophilic antioxidant and free radical scavenging action. Melatonin has been proven to be twice as active as vitamin E, believed to be the most effective lipophilic antioxidant. Melatonin-induced signal transduction through melatonin receptors promotes the expression of antioxidant enzymes as well as inflammation-related genes. Melatonin also exerts an immunomodulatory action through the stimulation of high-affinity receptors expressed in immunocompetent cells. Here, we reviewed the efficacy, safety and side effects of melatonin supplementation in treating oxidative stress- and/or inflammation-related disorders, such as obesity, cardiovascular diseases, immune disorders, infectious diseases, cancer, neurodegenerative diseases, as well as osteoporosis and infertility.