Cannabinoid therapies in the management of sleep disorders: A systematic review of preclinical and clinical studies

Is There a Place for Medicinal Cannabis in Treating Patients with Sleep Disorders? What We Know so Far

The legalization of cannabis for medicinal, and in some countries, recreational, purposes in addition to growth in the cannabis industry has meant that cannabis use and interest in the area has increased rapidly over the past 20 years. Treatment of poor sleep and sleep disorders are two of the most common reasons for the current use of medicinal cannabis. However, evidence for the role of medical cannabis in the treatment of sleep disorders has not been clearly established, thus making it challenging for clinicians to make evidence-based decisions regarding efficacy and safety. This narrative review summarizes the highest quality clinical evidence currently available in relation to the use of medicinal cannabis for the treatment of sleep disorders including insomnia, obstructive sleep apnea, restless legs syndrome, rapid eye movement sleep behavior disorder, nightmare disorder and narcolepsy. A summary of the effect of cannabis on sleep quality and architecture is also presented. Currently, there is insufficient evidence to support the routine use of medicinal cannabis as an effective and safe treatment option for any sleep disorder. Nevertheless, emerging evidence is promising and warrants further investigation using standardized cannabinoid products and validated quantitative measurement techniques.

Sleep and anxiety: From mechanisms to interventions

Anxiety is the most common mental health problem worldwide. Epidemiological studies show that sleep disturbances, particularly insomnia, affect ∼50% of individuals with anxiety, and that insufficient sleep can instigate or further exacerbate it. This review outlines brain mechanisms underlying sleep and anxiety, by addressing recent human functional/structural imaging studies on brain networks underlying the anxiogenic impact of sleep loss, and the beneficial effect of sleep on these brain networks. We discuss recent developments from human molecular imaging studies that highlight the role of specific brain neurotransmitter mechanisms, such as the adenosinergic receptor system, on anxiety, arousal, and sleep. This review further discusses frontline sleep interventions aimed at enhancing sleep in individuals experiencing anxiety, such as nonbenzodiazepines/antidepressants, lifestyle and sleep interventions and cognitive behavioral therapy for insomnia. Notwithstanding therapeutic success, up to ∼30% of individuals with anxiety can be nonresponsive to frontline treatments. Thus, we address novel non-invasive brain stimulation techniques that can enhance electroencephalographic slow waves, and might help alleviate sleep and anxiety symptoms. Collectively, these findings contribute to an emerging biological framework that elucidates the interrelationship between sleep and anxiety, and highlight the prospect of slow wave sleep as a potential therapeutic target for reducing anxiety.

Cannabis use as a moderator of cognitive behavioral therapy for insomnia

STUDY OBJECTIVES

Cannabis use is common among young adults and has been proposed as a potential treatment for insomnia. However, controlled studies examining the impact of cannabis use on insomnia symptoms are rare. This secondary analysis of published trial data tested cannabis use during cognitive behavioral treatment for insomnia (CBT-I) as a moderator of treatment efficacy.

METHODS

Young adults (ages 18-30 years) who reported past-month binge drinking (4/5+ drinks for women/men) and met DSM-5 and research diagnostic criteria for Insomnia Disorder were randomized to CBT-I (n=28) or sleep hygiene (SH; n=28). Interaction effects were tested using multilevel models. Outcomes included insomnia severity, actigraphy-assessed sleep efficiency, diary-assessed sleep quality, drinking quantity, and alcohol-related consequences.

RESULTS

Twenty-six participants (46%; 12 SH and 14 CBT-I) reported using cannabis during the treatment phase of the study, on an average of 23% of treatment days (range=3-100%). Relative to those who did not use cannabis, participants who used cannabis during treatment reported heavier drinking and more frequent cigarette use. Approximately 1 in 4 cannabis users (27%) reported using cannabis to help with sleep; however, cannabis and non-cannabis users did not differ in use of alcohol as a sleep aid. Controlling for sex, race, drinking quantity, cigarette use, symptoms of depression, and symptoms of anxiety, use of cannabis during treatment did not moderate CBT-I effects on insomnia severity (b= -.002, p=.99) or other outcomes (all p >.20).

CONCLUSIONS

CBT-I is effective in reducing insomnia symptoms among young adult drinkers with insomnia, regardless of cannabis use.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Identifier: NCT03627832.

The Management of Cancer Symptoms and Treatment-Induced Side Effects With Cannabis or Cannabinoids

Cannabis and cannabinoids are increasingly being accessed and used by patients with advanced cancer for various symptoms and general quality of life. Specific symptoms of pain, nausea and vomiting, loss of appetite and cachexia, anxiety, sleep disturbance, and medical trauma are among those that have prompted patients with cancer to use cannabis. This conference report from the National Cancer Institute's "Cannabis, Cannabinoid and Cancer Research Symposium" on the topic of "Cancer Symptom/Treatment Side Effect Management" is an expert perspective of cannabis intervention for cancer and cancer treatment-related symptoms. The purpose of the symposium was to identify research gaps, describe the need for high-quality randomized prospective studies of medical cannabis for palliative care in patients with cancer, and evaluate the impact of medical cannabis on cancer survivors' quality of life. Further, education of clinicians and affiliated health-care providers in guiding cancer patients in using cannabis for cancer care would benefit patients. Together, these steps will further aid in refining the use of cannabis and cannabinoids for symptom palliation and improve safety and efficacy for patients.

Treating insomnia symptoms with medicinal cannabis: a randomized, crossover trial of the efficacy of a cannabinoid medicine compared with placebo

STUDY OBJECTIVES

This randomized, double-blind, placebo-controlled, crossover study was conducted to evaluate the safety and efficacy of 2 weeks of nightly sublingual cannabinoid extract (ZTL-101) in treating chronic insomnia (symptoms ≥3 months).

METHODS

Co-primary study endpoints were safety of the medication based on adverse event reporting and global insomnia symptoms (Insomnia Severity Index [ISI]). Secondary endpoints included: self-reported (sleep diary), actigraphy-derived, and polysomnography measurements of sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), sleep efficiency (SE); and self-reported assessments of sleep quality (sSQ) and feeling rested upon waking. Adjusted mean differences between placebo and ZTL-101 were calculated.

RESULTS

Twenty-three of 24 randomized participants (n = 20 female, mean age 53 ± 9 years) completed the protocol. No serious adverse events were reported. Forty mild, nonserious, adverse events were reported (36 during ZTL-101) with all but one resolving overnight or soon after waking. Compared to placebo, ZTL-101 decreased ISI (-5.07 units [95% CI: -7.28 to -2.86]; p = 0.0001) and self-reported SOL (-8.45 min [95% CI: -16.33 to -0.57]; p = 0.04) and increased self-reported TST (64.6 min [95% CI: 41.70 to 87.46]; p < 0.0001), sSQ (0.74 units [95% CI: 0.51 to 0.97]; p < 0.0001), and feeling of being rested on waking (0.51 units [95% CI: 0.24 to 0.78]; p = 0.0007). ZTL-101 also decreased actigraphy-derived WASO (-10.2 min [95% CI: -16.2 to -4.2]; p = 0.002), and increased actigraphy-derived TST (33.4 min [95% CI: 23.07 to 43.76]; p < 0.001) and SE (2.9% [95% CI: 2.0 to 3.8]; p = 0.005).

CONCLUSIONS

Two weeks of nightly sublingual administration of a cannabinoid extract (ZTL-101) is well tolerated and improves insomnia symptoms and sleep quality in individuals with chronic insomnia symptoms.

CLINICAL TRIAL

ANZCTR; anzctr.org.au; ACTRN12618000078257.

Medical Cannabis and Cannabinoids for Impaired Sleep: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

STUDY OBJECTIVES

We conducted a systematic review to explore the effectiveness of medical cannabis for impaired sleep.

METHODS

We searched MEDLINE, EMBASE, CENTRAL and PsychINFO to January 2021 for randomized trials of medical cannabis or cannabinoids for impaired sleep vs. any non-cannabis control. When possible, we pooled effect estimates for all patient-important sleep-related outcomes and used the GRADE approach to appraise the certainty of evidence.

RESULTS

Thirty-nine trials (5,100 patients) were eligible for review, of which 38 evaluated oral cannabinoids and 1 administered inhaled cannabis. The median follow-up was 35 days, and most trials (33 of 39) enrolled patients living with chronic cancer or noncancer chronic pain. Among patients with chronic pain, moderate certainty evidence found that medical cannabis probably results in a small improvement in sleep quality versus placebo (modeled risk difference [RD] for achieving the minimally important difference [MID], 8% [95% CI, 3 to 12]). Moderate to high certainty evidence shows that medical cannabis vs. placebo results in a small improvement in sleep disturbance for chronic non-cancer pain (modeled RD for achieving the MID, 19% [95% CI, 11 to 28]) and a very small improvement in sleep disturbance for chronic cancer pain (WMD of -0.19cm [95%CI, -0.36 to -0.03cm]; interaction p=0.03). Moderate to high certainty evidence shows medical cannabis, versus placebo, results in a substantial increase in the risk of dizziness (RD 29% [95%CI, 16 to 50], for trials with ≥3 months follow-up), and a small increase in the risk of somnolence, dry mouth, fatigue, and nausea (RDs ranged from 6% to 10%).

CONCLUSION

Medical cannabis and cannabinoids may improve impaired sleep among people living with chronic pain, but the magnitude of benefit is likely small.

Potential Role of Cannabidiol on Sports Recovery: A Narrative Review

The use of cannabidiol (CBD) among athletes is becoming extensive and frequent. This could be due to the elimination of CBD from the list of prohibited substances by federations and international institutions of sport. The legalization and resulting production, and commercialization of CBD, could increase its intake in sports professionals. This commercialization of cannabinoids has fueled a race to study their properties, benefits, and risks for health and performance in athletes. Although there is evidence that suggests some beneficial properties such as anxiolytics, antidepressants, anti-inflammatory, and antioxidants among others, the evidence presented so far is neither clear nor conclusive. There are significant gaps in knowledge of the physiological pathways that explain the role of CBD in sports performance. This mini-review examines evidence suggesting that CBD has the potential to be used as a part of the strategies to recover from fatigue and muscle damage related to physical and cognitive exertion in sports.

Origin and Evolution of the Cannabinoid Oxidocyclase Gene Family

Cannabis is an ancient crop representing a rapidly increasing legal market, especially for medicinal purposes. Medicinal and psychoactive effects of Cannabis rely on specific terpenophenolic ligands named cannabinoids. Recent whole-genome sequencing efforts have uncovered variation in multiple genes encoding the final steps in cannabinoid biosynthesis. However, the origin, evolution, and phylogenetic relationships of these cannabinoid oxidocyclase genes remain unclear. To elucidate these aspects, we performed comparative genomic analyses of Cannabis, related genera within the Cannabaceae family, and selected outgroup species. Results show that cannabinoid oxidocyclase genes originated in the Cannabis lineage from within a larger gene expansion in the Cannabaceae family. Localization and divergence of oxidocyclase genes in the Cannabis genome revealed two main syntenic blocks, each comprising tandemly repeated cannabinoid oxidocyclase genes. By comparing these blocks with those in genomes from closely related species, we propose an evolutionary model for the origin, neofunctionalization, duplication, and diversification of cannabinoid oxidocycloase genes. Based on phylogenetic analyses, we propose a comprehensive classification of three main clades and seven subclades that are intended to aid unequivocal referencing and identification of cannabinoid oxidocyclase genes. Our data suggest that cannabinoid phenotype is primarily determined by the presence/absence of single-copy genes. Although wild populations of Cannabis are still unknown, increased sampling of landraces and wild/feral populations across its native geographic range is likely to uncover additional cannabinoid oxidocyclase sequence variants.

At the intersection of sleep deficiency and opioid use: mechanisms and therapeutic opportunities

Due to the ongoing opioid epidemic, innovative scientific perspectives and approaches are urgently needed to reduce the unprecedented personal and societal burdens of nonmedical and recreational opioid use. One promising opportunity is to focus on the relationship between sleep deficiency and opioid use. In this review, we examine empirical evidence: (1) at the interface of sleep deficiency and opioid use, including hypothesized bidirectional associations between sleep efficiency and opioid abstinence; (2) as to whether normalization of sleep deficiency might directly or indirectly improve opioid abstinence (and vice versa); and (3) regarding mechanisms that could link improvements in sleep to opioid abstinence. Based on available data, we identify candidate sleep-restorative therapeutic approaches that should be examined in rigorous clinical trials.

Building risk prediction models for daily use of marijuana using machine learning techniques

Identifying the characteristics of adults with recent marijuana use is limited by standard statistical methods and requires a unique approach. The objective of this study is to evaluate the efficiency of machine learning models in predicting daily marijuana use and identify factors associated with daily use among adults. The study analyzed pooled data from the 2016-2019 Behavioral Risk Factor Surveillance System (BRFSS) Survey in 2020. Prediction models were developed using four machine learning algorithms, including Logistic Regression, Decision Tree, and Random Forest with Gini function, and Naïve Bayes. Respondents were randomly divided into training and testing samples. The performance of all the models was compared using accuracy, AUC, precision, and recall. The study included 253,569 respondents, of whom 10,182 (5.9 %) reported daily marijuana use in the last 30 days. Of daily marijuana use, 53.4 % were young adults (age 18-34 years), 34.3 % female, 56.1 % non-Hispanic White, 15.2 % were college graduates, and 67.3 % were employed. Random Forest was the best performing model with AUC 0.97, followed by a Decision tree (AUC 0.95). The most important factors for daily marijuana use were the current use of e-cigarette and combustible cigarette use, male gender, unmarried, poor mental health, depression, cognitive decline, abnormal sleep pattern, and high-risk behavior. Data mining methods were useful in the discovery of behavior health-risk knowledge and to visualize the significance of predicting modeling from a multidimensional behavioral health survey.

Insomnia: Pharmacologic Treatment

Insomnia afflicts many geriatric patients worldwide and results in both clinical and economic consequences. Prescribing hypnotics to the elderly is particularly challenging due to multitudes of adverse effects and drug interactions. Although benzodiazepines and "Z" drugs such as zolpidem have been popular in the past, they carry a high risk of adverse effects in the elderly, such as devastating falls and injuries as well as potentially an increase in mortality. Newer classes of hypnotics such as dual orexin receptor antagonists are much better tolerated and can be explored as a potential treatment for insomnia in the elderly.

Changes in sleep-wake cycle after microinjection of agonist and antagonist of endocannabinoid receptors at the medial septum of rats

The role of medial septum in the genesis of slow-wave sleep and the inhibition of rapid eye movement sleep has been established using neurotoxic lesion and chemical stimulation of the medial septum. Intracerebroventricular injection of endocannabinoids (anandamide) decreases wake and increases slow-wave and rapid eye movement sleep in rats. Central cannabinoid (CB1) receptors are localized in the rat medial septum; however, the role of cannabinoid receptors at the medial septum on the regulation of sleep-wakefulness in rats lacks evidence. In this study, we have examined the changes in sleep architecture of 21 male Wistar rats, divided into three groups. Initially, 6 rats were used for dose standardization. Subsequently, one group (n = 6) was microinjected with CB1 receptor agonist, R-(+)-WIN 55,212-2 mesylate salt, the second group (n = 6) received microinjection of CB1 receptor antagonist LY 320,135, and the third group (n = 5) was microinjected with the vehicle, DMSO at the medial septum using stereotaxy. The sleep-wake cycle was recorded using electroencephalogram, electro-oculogram, and electromyogram. Microinjection of CB1 receptor agonist at the medial septum decreased slow-wave sleep and increased total sleep time. The increase in total sleep time was due to an increased percentage of rapid eye movement sleep. After the third and fourth hour of CB1 receptor antagonist microinjection at the medial septum, slow-wave sleep decreased when compared to vehicle injection, while rapid eye movement sleep decreased compared to baseline. We conclude that the endocannabinoid system at the septal nucleus acts through CB1 receptors to increase rapid eye movement sleep in rats.

Endocannabinoid System as Therapeutic Target of PTSD: A Systematic Review

Post-Traumatic Stress Disorder (PTSD) is a complex disorder involving dysregulation of stress-related hormones and neurotransmitter systems. Research focused on the endocannabinoid system (eCBS) for anxiety and stress regulation, cognitive and emotional responses modulation and aversive memories extinction, leading to the hypothesis that it could represent a possible alternative treatment target for PTSD. In this systematic review, we summarize evidence about the efficacy and safety of medicinal cannabidiol (CBD), Δ⁹-tetrahydrocannabinol (Δ⁹-THC), and nabilone in PTSD treatment. The PRISMA statement guidelines were followed. A systematic literature search was conducted in MEDLINE/PubMed, Scopus and Web of Science by two independent researchers, who also performed data extraction and quality assessment. Among the initial 495 papers, 234 were screened for eligibility and 10 were included. Studies suggested that different medicinal cannabinoids at distinct doses and formulations could represent promising treatment strategies for the improvement of overall PTSD symptomatology as well as specific symptom domains (e.g., sleep disorders, arousal disturbances, suicidal thoughts), also influencing quality of life, pain and social impact. Although there is a robust rationale for treatment with drugs that target the eCBS and the results are promising, further studies are needed to investigate the safety and efficacy profile of their prolonged use.

Multitargeting the sleep-pain interaction with pharmacological approaches: A narrative review with suggestions on new avenues of investigation

The multimorbidity formed by sleep disturbances and pain conditions is highly prevalent and has a significant impact in global health and in the socioeconomic system. Although different approaches have been directed toward its management, evidence regarding an optimal treatment is lacking, and pharmacological options are often preferred. Health professionals (e.g., pain and sleep clinicians) tend to focus on their respective expertise, targeting a single symptom with a single drug. This may increase polypharmacy and the risk of drug interactions, adverse events, and mortality. Hence, the use of medications that can directly or indirectly improve sleep, pain, and other possible accompanying conditions without exacerbating them becomes especially relevant. The objectives of this comprehensive review are to: a) describe the beneficial or deleterious effects that some commonly used medications to manage pain have on sleep and sleep disorders; and b) describe the beneficial or deleterious effects that frequently prescribed medications for sleep may have on pain. Moreover, medications targeting some specific sleep-pain interactions will be suggested and future directions for improving sleep and alleviating pain of these patients will be provided with clinical and research perspectives.

Effects of Cannabinoids on Sleep and their Therapeutic Potential for Sleep Disorders

The recent trend for legalization of medicinal cannabis and cannabinoid-containing products, together with their soporific effects, has led to a surge of interest of their potential therapeutic role in the management of some common sleep disorders, such as insomnia, sleep disordered breathing, and restless legs syndrome, and less common disorders such as narcolepsy and parasomnias. Although much of the pre-clinical and clinical data were derived from studies with relatively small sample sizes and limited by biases in assessment, and in clinical trials lack of allocation concealment, as a whole, the results indicate a potential therapeutic role for cannabinoids in the management of some sleep disorders. Clinical trials are underway for insomnia and obstructive sleep apnea management, but there remains a substantial need for rigorous large multi-center studies to assess the dose, efficacy, and safety of the various types of cannabinoids on sleep disorders. This review aims to summarize the modulatory effects of cannabinoids on sleep physiology and provide a critical evaluation of the research on their potential therapeutic benefit in various sleep disorders.

Safety and efficacy of low-dose medical cannabis oils in multiple sclerosis

INTRODUCTION

The use of cannabis as medical therapy to treat chronic pain and spasticity in patients with multiple sclerosis (MS) is increasing. However, the evidence on safety when initiating treatment with medical cannabis oils is limited. The aim of this study was to investigate the safety of sublingual medical cannabis oils in patients with MS.

METHODS

In this prospective observational safety study 28 patients with MS were treated with medical cannabis oils (THC-rich, CBD-rich and THC+CBD combined products) and were followed during a titration period of four weeks. Patients were evaluated at treatment start (Visit 1) and after four weeks treatment (Visit 2). At each visit neurological examination (Expanded Disability Status Scale - EDSS), ambulation (Timed 25-Foot Walk Test - T25FWT), routine blood tests, plasma cannabinoids, dexterity (9-Hole Peg Test - 9-HPT) and processing speed (Symbol Digit Modalities Test - SDMT) were tested. Adverse events (AEs) and tolerability were reported at Visit 2. Secondary, efficacy of medical cannabis on pain, spasticity and sleep disturbances were measured by numeric rating scale (NRS-11) each day during the 4-week treatment period.

RESULTS

During treatment with cannabis preparations containing 10-25 mg/mL THC, the most common AEs were dry mouth, drowsiness, dizziness and nausea of mild to moderate degree. Two patients experienced pronounced symptoms with excessive dreaming and drowsiness, respectively, which led to treatment stop during the titration. Three serious adverse events (SAE) were reported but were not associated with the treatment. Mean doses of THC and CBD were 4.0 mg and 7.0 mg, respectively, and primarily administered as a once-daily evening dose. Furthermore, pain decreased from a median NRS score of 7 to 4, (p = 0.01), spasticity decreased from a median NRS score of 6 to 2.5 (p = 0.01) and sleep disturbances decreased from a median NRS score of 7 to 3 (p < 0.001). No impairment in disability, ambulation, dexterity or processing speed was observed.

CONCLUSION

Treatment with medical cannabis oils was safe and well tolerated, and resulted in a reduction in pain intensity, spasticity and sleep disturbances in MS patients. This suggests that medical cannabis oils can be used safely, especially at relatively low doses and with slow titration, as an alternative to treat MS-related symptoms when conventional therapy is inadequate.

Distinctive Evidence Involved in the Role of Endocannabinoid Signalling in Parkinson's Disease: A Perspective on Associated Therapeutic Interventions

Current pharmacotherapy of Parkinson's disease (PD) is symptomatic and palliative, with levodopa/carbidopa therapy remaining the prime treatment, and nevertheless, being unable to modulate the progression of the neurodegeneration. No available treatment for PD can enhance the patient's life-quality by regressing this diseased state. Various studies have encouraged the enrichment of treatment possibilities by discovering the association of the effects of the endocannabinoid system (ECS) in PD. These reviews delineate the reported evidence from the literature on the neuromodulatory role of the endocannabinoid system and expression of cannabinoid receptors in symptomatology, cause, and treatment of PD progression, wherein cannabinoid (CB) signalling experiences alterations of biphasic pattern during PD progression. Published papers to date were searched via MEDLINE, PubMed, etc., using specific key words in the topic of our manuscript. Endocannabinoids regulate the basal ganglia neuronal circuit pathways, synaptic plasticity, and motor functions via communication with dopaminergic, glutamatergic, and GABAergic signalling systems bidirectionally in PD. Further, gripping preclinical and clinical studies demonstrate the context regarding the cannabinoid compounds, which is supported by various evidence (neuroprotection, suppression of excitotoxicity, oxidative stress, glial activation, and additional benefits) provided by cannabinoid-like compounds (much research addresses the direct regulation of cannabinoids with dopamine transmission and other signalling pathways in PD). More data related to endocannabinoids efficacy, safety, and pharmacokinetic profiles need to be explored, providing better insights into their potential to ameliorate or even regress PD.

Astrocytes Function as an Intermediate for Retrograde Endocannabinoid Signaling in the Suprachiasmatic Nucleus to Influence Circadian Clock Timing

Highlighted Research Paper:Cannabinoid Signaling Recruits Astrocytes to Modulate Presynaptic Function in the Suprachiasmatic Nucleus. Lauren M. Hablitz, Ali N. Gunesch, Olga Cravetchi, Michael Moldavan and Charles N. Allen.