Targeting Orexin Receptors for the Treatment of Insomnia: From Physiological Mechanisms to Current Clinical Evidence and Recommendations

A new direction for adjunctive therapy of difficult-to-treat depression: examining the role of orexin receptor antagonists

One of the several pressing unmet needs in the pharmacotherapy of MDD is development of drugs with novel mechanisms of action that can effectively treat depressed patients who do not respond to first- and second-line antidepressants. The value of identifying such a medication would be enhanced if it were also generally well-tolerated and addressed depressive symptoms that are less responsive to SSRIs or SNRIs, such as insomnia or anxiety. This narrative review summarizes the investigation of a novel class of medications originally developed to treat insomnia, the Orexin Receptor Antagonists (ORAs), as adjunctive treatments for depressed patients who have been able to tolerate but who do not obtain an adequate response to standard antidepressants. Although it is likely that the currently approved Dual Orexin Receptor Antagonists (DORAs)-suvorexant, lemborexant and daridorexant-are safe and useful options for concomitant therapy of insomnia in antidepressant-treated patients, these medications have not been approved for this indication. Moreover, DORAs have not been extensively studied as adjunctive therapies for MDD. By contrast, the investigational ORA seltorexant, which is a selective Orexin 2 receptor antagonist, has shown significant antidepressant effects in Phase 2 and Phase 3 trials. Although at least one more unequivocally positive pivotal study will be needed to garner FDA approval for clinical use in the United States, this drug shows promise as a novel and well-tolerated option for patients with difficult to treat depressive episodes.

A Systematic Review of the Effects of Repetitive Transcranial Magnetic Stimulation Combined With Pharmacological Intervention on Sleep Quality and Depressive Symptoms in Patients With Depression

To systematically evaluate the intervention effect of repetitive transcranial magnetic stimulation (rTMS) combined with pharmacological interventions on sleep quality and depressive symptoms in patients with depression, identify optimal stimulation parameters, and explore potential clinical applications to facilitate individualised therapeutic strategies. Databases including Pubmed, Web of Science, Cochrane Library, Embase, CNKI, Wanfang Medical Database, and VIP database were searched up to 31 December 2024, for randomized controlled trials (RCTs) assessing rTMS combined with pharmacological intervention for sleep disorders and depressive symptoms in patients with depression. Data analysis was performed using Stata software. 17 RCTs involving 1667 patients were included. Meta-analysis revealed that rTMS significantly improved sleep quality (SMD = -0.57, 95% CI: -1.02 to -0.12, P < 0.05) and reduced depressive symptoms (SMD = -0.73, 95% CI: -1.37 to -0.10, P < 0.05). Subgroup analyses showed that the optimal parameters for improving sleep quality were high-frequency rTMS targeting the left dorsolateral prefrontal cortex, high stimulation intensity, low total pulse count (< 1200 pulses), session duration ≤ 20 min daily, for 5-8 weeks. For depressive symptoms, a daily treatment duration of 21-30 min was more effective under similar parameter conditions. rTMS effectively improves sleep quality and alleviates depressive symptoms in patients with depression, showing a dose-dependent effect with stimulation parameters. However, in patients with a prolonged disease course or greater symptom severity, particularly those with vascular and other neurological comorbidities, rTMS alone may be insufficient. Integrating additional therapeutic strategies or tailoring personalised treatment protocols may be necessary to optimise clinical outcomes. Future research should further explore the synergistic potential of rTMS combined with orexin receptor antagonists (ORAs), offering a novel, multimodal approach for managing depression with comorbid insomnia.

Orexin receptors: possible therapeutic targets for psychiatric disorders

RATIONALE

Orexins, comprising orexin-A and orexin-B, are neuropeptides with extensive projections throughout the central nervous system. They are implicated in a variety of physiological processes through their receptors, orexin type 1 (OX1) and orexin type 2 (OX2) receptors. Among the physiological functions of orexins, their role in sleep/wake regulation has garnered significant attention. Consequently, three orexin receptor antagonists that block both OX1 and OX2 receptors (dual orexin receptor antagonist; DORA) are available on the market for the treatment of insomnia. Additionally, another DORA, vornorexant, has been submitted for approval.

OBJECTIVE

Beyond sleep disorders, the orexin system is deeply implicated in the pathophysiology of several psychiatric disorders, including depression, anxiety, and substance use disorders.

RESULTS

Accumulating evidence indicates that orexin receptor antagonists improve behavioral abnormalities that mimic certain psychiatric disorders in animal models and are effective in treating these disorders or their symptoms in humans. Moreover, orexin receptor antagonists are expected not only to alleviate core symptoms of psychiatric disorders but also to improve sleep disturbances, which are often comorbid with these conditions.

CONCLUSION

Drug discovery and development targeting orexin receptors should provide novel therapeutic options for the treatment of psychiatric disorders.

A randomised crossover trial of daridorexant for the treatment of chronic insomnia and nocturia

This double-blind, placebo-controlled, two-way crossover trial evaluated the efficacy and safety of daridorexant in patients with chronic insomnia and comorbid nocturia. In total, 60 patients aged ≥55 years with insomnia complaints for ≥3 months, Insomnia Severity Index (ISI) ≥13 and ≥3 voids/night for ≥1 month were randomised (1:1) to daridorexant 50 mg/placebo for 4 weeks followed by crossover after a 14-21-day washout period. The primary endpoint was change from baseline to Week (W) 4 in self-reported total sleep time (sTST). Other endpoints included change in ISI score, sleep depth and quality (visual analogue scale scores), nocturnal voids (mean number, time to first) and daytime functioning (Insomnia Daytime Symptoms and Impacts Questionnaire score [IDSIQ]). At W4, daridorexant significantly increased sTST versus placebo (least-squares mean difference [LSMD] 20.9 min, 95% confidence interval [CI] 8.0-33.7; p = 0.002); significant improvements were also seen at W1-3. Compared with placebo, daridorexant significantly decreased (p < 0.001) ISI at both timepoints, W2 (LSMD -3.7, 95% CI -5.1 to -2.3) and W4 (LSMD -3.3, 95% CI -4.7 to -1.8) and significantly improved (p < 0.05) sleep depth (W1, 2, 3, 4), sleep quality (W1, 2, 3) and IDSIQ total score (W1, 3). Daridorexant versus placebo reduced the number of voids (LSMD [95% CI]: W1-0.6 [-0.9 to -0.3], p < 0.001; W4-0.3 [-0.7 to +0.1], p = 0.090) and increased median time to first void (difference to placebo, W1: +31 min, p = 0.0027; W4: +23 min, p = 0.2026). No adverse events of special interest (falls/urinary incontinence) were reported during daridorexant treatment. In conclusion, in patients with chronic insomnia and nocturia, daridorexant improves both conditions with a favourable safety profile.

The Orexin System and Its Impact on the Autonomic Nervous and Cardiometabolic System in Post-Acute Sequelae of COVID-19

Orexins (OXs) are critical for regulating circadian rhythms, arousal, appetite, energy metabolism, and electrolyte balance, affecting both the autonomic nervous system (ANS) and the cardiovascular system (CVS). Disruption of the OX system can result in symptoms similar to those observed in post-acute sequelae of COVID-19 (PASC). This review emphasizes the adverse effects of OX dysregulation on autonomic and cardiometabolic functions in patients with PASC. Additionally, we highlight the potential of anti-OX therapies to provide neuroprotective, anti-inflammatory, and immunoregulatory benefits, offering hope for alleviating some of the debilitating symptoms associated with PASC.

Intersection of Sleep Disorders and Parkinson Disease: Unveiling the Bidirectional Relationship

BACKGROUND

Patients with Parkinson's Disease (PD) frequently exhibit non-motor symptoms, particularly sleep disturbances. Sleep disorders in PD patients are intricately linked to the pathogenesis and progression of PD itself, exacerbating neurodegenerative processes and worsening patient quality of life.

OBJECTIVES

This review underscores the significance of sleep disorders in PD, highlighting their prevalence, impact on disease progression, and the bidirectional relationship between sleep disruption and neurodegeneration. It aims to enhance clinician awareness for better diagnosis and management of sleep-related comorbidities in PD.

METHODS

A comprehensive literature search was conducted in PubMed and Scopus using key terms such as "sleep disorders", "Parkinson's disease", "REM sleep behavior disorder", "restless legs syndrome", "insomnia", "obstructive sleep apnea", "excessive daytime sleepiness", "circadian rhythm disorders", "sleep and neurodegeneration".

RESULTS

Sleep disorders are prevalent in PD affecting up to 90% of patients. Conditions such as insomnia, REM sleep behavior disorder, restless legs syndrome, obstructive sleep apnea, excessive daytime sleepiness, and circadian rhythm disorders are commonly reported. These disorders are linked to multifactorial biological mechanisms and are associated with more severe disease phenotypes. Of note, several evidence shows that sleep abnormalities may contribute to neuroinflammation and neurodegeneration, further accelerating the disease course.

CONCLUSIONS

Sleep disturbances are critical non-motor symptoms in PD. Early diagnosis and tailored management of sleep disorders are essential for improving clinical outcomes and potentially offering neuroprotective benefits.

Preliminary examination of orexin receptor antagonism with suvorexant in individuals with Methamphetamine use disorder: a case series study

Background: No FDA-approved medications for methamphetamine (MA) use disorder (MUD) are available. Suvorexant (SUVO), a dual orexin receptor antagonist that is FDA approved for insomnia treatment, reduces MA self-administration and MA-induced reinstatement responding in preclinical studies. SUVO may also reduce MA use by targeting substance use risk factors, including insomnia, stress, cue reactivity, and craving. This case series study assessed the (1) feasibility and safety of administering suvorexant in a sample of individuals with MUD; and (2) preliminary effects of suvorexant on objective and subjective measures of sleep, stress, and cue reactivity/craving. Method: Participants (n = 3) were randomized to receive 1 week of SUVO or placebo using a within-subject, crossover design with a 1-week washout period between doses. Participants completed self-report (sleep quality, stress), behavioral (cold pressor task), and physiological measures (heart rate, electroencephalogram) during all three weeks. Participants wore a Fitbit to monitor sleep throughout the study. Results: Participants completed all study visits and tasks. One report of severe drowsiness and of severe headache were made; no other severe side effects were associated with SUVO. SUVO improved total sleep time and resulted in lower resting-state alpha power, but was mixed for subjective sleep quality. SUVO administration was associated with increased overall brain reactivity to cues that was not specific to MA cues and also reduced stress, though self-reported stress demonstrated mixed results. Conclusion: Suvorexant was safe and tolerable in a MUD sample. Future research may benefit from investigating SUVO in a well-controlled study with a larger sample.

Orexin Receptor Antagonists for the Prevention and Treatment of Alzheimer's Disease and Associated Sleep Disorders

Orexins/hypocretins are neuropeptides produced by the hypothalamic neurons, binding two G-protein coupled receptors (orexin 1 and orexin 2 receptors) and playing a critical role in regulating arousal, wakefulness, and various physiological functions. Given the high prevalence of sleep disturbances in Alzheimer's disease (AD) and their reported involvement in AD pathophysiology, the orexin system is hypothesized to contribute to the disease pathogenesis. Specifically, recent evidence suggests that orexin's influence may extend beyond sleep regulation, potentially affecting amyloid-β and tau pathologies. Dual orexin receptor antagonists (DORAs), namely suvorexant, lemborexant, and daridorexant, demonstrated efficacy in treating chronic insomnia disorder across diverse clinical populations. Considering their stabilizing effects on sleep parameters and emerging evidence of a possible neuroprotective role, these agents represent a promising strategy for AD management. This leading article reviews the potential use of orexin receptor antagonists in AD, particularly focusing on their effect in modulating disease-associated sleep disturbances and clinical outcomes. Overall, clinical studies support the use of DORAs to enhance sleep quality in patients with AD with comorbid sleep and circadian sleep-wake rhythm disorders. Preliminary results also suggest that these compounds might influence AD pathology, potentially affecting disease progression. Conversely, research on selective orexin receptor antagonists in AD is currently limited. Further investigation is needed to explore orexin antagonism not only as a symptomatic treatment for sleep disturbances, but also for its broader implications in modifying AD neurodegeneration, emphasizing mechanisms of action and long-term outcomes.

Clinical safety of daridorexant in insomnia treatment: Analysis of FDA adverse event reports

OBJECTIVE

Daridorexant, a novel dual orexin receptor antagonist, was approved by the FDA in 2022 for the treatment of insomnia in adults. The aim of this study is to delve into the adverse events (AEs) of daridorexant by analyzing data from the FAERS database, to assess its safety and effectiveness in clinical applications.

METHODS

This study selected data from the FAERS database from the first quarter of 2022 to the third quarter of 2023. Various data analysis methods were used, including the Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Empirical Bayesian Geometric Mean (EBGM), to assess AEs related to daridorexant.

RESULTS

The study analyzed a total of 2,624,030 AE reports, of which 1318 were related to daridorexant. It identified 59 preferred terms (PTs) involving 23 system organ classes (SOCs). Signal mining identified new potential AEs related to daridorexant, including sleep-related psychiatric symptoms (nightmare, abnormal dreams, sleep terror, etc.), emotional and perceptual abnormalities (hallucination, depression, agitation), physiological and behavioral responses (palpitations, dry mouth, energy increased, etc.), suicide risk (suicidal ideation, intentional overdose), and other special concern AEs (tachyphrenia, sleep-related eating disorder, hypersensitivity).

CONCLUSION

Although some new potential AEs have been identified, these findings need further verification in broader datasets and long-term studies due to limitations in data sources and analysis methods. Future research should comprehensively assess the safety and effectiveness of daridorexant, providing more accurate guidance for medical professionals in the treatment of insomnia.

Individualized approaches to pediatric chronic insomnia: Advancing precision medicine in sleep disorders

The manifestations of chronic insomnia undergo age-related changes. In younger infants and children, behavioral insomnia emerges as the most prevalent form and typically responds to behavioral interventions. However, distinct clusters of clinical presentations suggest the presence of various phenotypes, potentially implicating the primary involvement of specific neurotransmitters. These conceptualizations, coupled with genetic studies on pleiotropy and polygenicity, may aid in identifying individuals at risk of persistent insomnia into adulthood and shed light on novel treatment options. In school-age children, the predominant presentation is sleep-onset insomnia, often linked with nighttime fears, anxiety symptoms, poor sleep hygiene, limit-setting issues, and inadequate sleep duration. The manifestations of insomnia in adolescence correlate with the profound changes occurring in sleep architecture, circadian rhythms, and homeostatic processes. The primary symptoms during adolescence include delayed sleep onset, sleep misperception, persistent negative thoughts about sleep, and physiological hyperarousal-paralleling features observed in adult insomnia. An approach centered on distinct presentations may provide a framework for precision-based treatment options. Enhanced comprehension of insomnia's manifestations across diverse developmental stages can facilitate accurate assessment. Efforts to subtype insomnia in childhood align with this objective, potentially guiding the selection of appropriate treatments tailored to individual neurobiological, clinical, and familial features.

The Triad of Sleep, Immunity, and Cancer: A Mediating Perspective

The triadic interplay between sleep, immunity, and cancer represents a growing area of biomedical research with significant clinical implications. This review synthesizes the current knowledge on how sleep influences immune function, the immune system's role in cancer dynamics, and the direct connections between sleep patterns and cancer risk. After a comprehensive overview of the interrelationships among these three domains, the mechanisms of sleep in immune function are described, detailing how sleep regulates the immune system, the effects of sleep duration and quality on immune responses, and the underlying molecular and cellular mechanisms. Also, the complex relationship between immunity and cancer is explored, highlighting the immune system's role in cancer prevention and progression, immune surveillance, tumor microenvironment, and the implications of immunodeficiency and immune modulation on cancer risk. The direct connections between sleep and cancer are then described, presenting epidemiological evidence linking sleep patterns to cancer risk, biological mechanisms that influence cancer development, and the role of sleep disorders in cancer prognosis. The mediating role of sleep between immunity and cancer is highlighted, proposing hypothesized pathways, summarizing evidence from experimental and clinical studies, and evaluating the impact of sleep interventions on immune function and cancer outcomes. This review concludes by discussing the clinical implications and future directions, emphasizing the potential for sleep-based interventions in cancer prevention and treatment, the integration of sleep management in oncology and immunotherapy, and outlining a future research agenda. This agenda includes understanding the mechanisms of the sleep-immunity-cancer interplay, conducting epidemiological studies on sleep and cancer risk, assessing the impact of sleep management in cancer treatment protocols, exploring sleep and tumor microenvironment interactions, and considering policy and public health implications. Through a detailed examination of these interconnected pathways, this review underscores the critical importance of sleep in modulating immune function and cancer outcomes, advocating for interdisciplinary research and clinical strategies to harness this knowledge for improved health outcomes.

Daridorexant treatment for chronic insomnia: a real-world retrospective single-center study

INTRODUCTION

Chronic insomnia disorder (CID) significantly impacts well-being and daily functioning. Daridorexant, a double orexin receptor blocker, has shown efficacy in randomized clinical trials and has been recently approved for the treatment of CID in adult patients. This retrospective observational study aimed to describe real-world data on daridorexant effectiveness and safety in adult patients with CID.

METHODS

Consecutive patients initiating on-label daridorexant at the Sleep Medicine Centre, University Hospital of Rome Tor Vergata were enrolled. Baseline and 30-day follow-up (FU) evaluations included patients' and CID characteristics, comorbidities, and clinicians' and patients' subjective ratings of changes with the Clinical and Patient Global Impression-Improvement scores (CGI-Is and PGI-Is), as well as Insomnia Severity Index (ISI) scores in a subgroup of patients.

RESULTS

Sixty-nine patients initiated 50-mg daily dosage. At FU, 58% of both patients and clinicians rated CID as improved on CGI-Is and PGI-Is, with no differences based on comorbidities, sex, or number of previous medications. No significant predictors of CGI-Is and PGI-Is improvement were identified. At FU, ISI scores (n = 24) significantly decreased from 18.25 ± 3.21 to 12.08 ± 6.12 (Z = 8.000; p < 0.001). Of these, eight patients (33.3%) had absence of insomnia symptoms, and no patients reported a worsening in ISI score categories.

CONCLUSIONS

This study suggests daridorexant to be effective and safe in real-world CID treatment whether used as a first-ever treatment, switch, or add-on, as reflected by subjective and objective measures and the absence of serious treatment-related adverse events. Future research on larger cohorts should explore daridorexant potential across diverse patient characteristics.

Assessing the Real-World, Long-Term Impact of Lemborexant on Sleep Quality in a Home-Based Clinical Study

Purpose

Both subjective and objective evaluations are essential for the treatment of insomnia. Lemborexant has been shown to be effective in the long-term based solely on a subjective basis, and no long-term objective measures have been evaluated under natural sleep conditions. Small, lightweight sleep electroencephalogram (EEG) monitor was used, instead of polysomnography, to objectively evaluate sleep at home 4 and 12 weeks after lemborexant treatment.

Patients and Methods

Adults and elderly subjects with insomnia disorder, per the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, were enrolled in this open-label, single-arm, single-center trial. Objective and subjective measures of sleep were prospectively assessed. Sleep disturbance, excessive sleepiness, and depressive symptoms were assessed using questionnaires.

Results

A total of 45 subjects were screened, of which 33 were enrolled. Paired t-tests were conducted to evaluate changes in sleep variables and compared with the baseline; subjects showed significant improvements in objective sleep efficiency (SE) and subjective sleep parameters at weeks 4 and 12 following treatment with lemborexant. When baseline values were taken into account, a repeated-multivariate analysis of variance (MANOVA) revealed statistically significant changes in the objective measures. Sleep disturbance, excessive sleepiness, and depressive symptoms improved after three months of lemborexant treatment.

Conclusion

Furthermore, lemborexant therapy improved nocturnal sleep, when measured objectively using sleep EEG monitoring at home, and improved daytime sleepiness and depressive symptoms in older adults with insomnia disorder.

Sleep disorders and cancer incidence: examining duration and severity of diagnosis among veterans

Introduction

Sleep disruption affects biological processes that facilitate carcinogenesis. This retrospective cohort study used de-identified data from the Veterans Administration (VA) electronic medical record system to test the hypothesis that patients with diagnosed sleep disorders had an increased risk of prostate, breast, colorectal, or other cancers (1999-2010, N=663,869). This study builds upon existing evidence by examining whether patients with more severe or longer-duration diagnoses were at a greater risk of these cancers relative to those with a less severe or shorter duration sleep disorder.

Methods

Incident cancer cases were identified in the VA Tumor Registry and sleep disorders were defined by International Classification of Sleep Disorder codes. Analyses were performed using extended Cox regression with sleep disorder diagnosis as a time-varying covariate.

Results

Sleep disorders were present among 56,055 eligible patients (8% of the study population); sleep apnea (46%) and insomnia (40%) were the most common diagnoses. There were 18,181 cancer diagnoses (41% prostate, 12% colorectal, 1% female breast, 46% other). The hazard ratio (HR) for a cancer diagnosis was 1.45 (95% confidence interval [CI]: 1.37, 1.54) among those with any sleep disorder, after adjustment for age, sex, state of residence, and marital status. Risks increased with increasing sleep disorder duration (short [<1-2 years] HR: 1.04 [CI: 1.03-1.06], medium [>2-5 years] 1.23 [1.16-1.32]; long [>5-12 years] 1.52 [1.34-1.73]). Risks also increased with increasing sleep disorder severity using cumulative sleep disorder treatments as a surrogate exposure; African Americans with more severe disorders had greater risks relative to those with fewer treatments and other race groups. Results among patients with only sleep apnea, insomnia, or another sleep disorder were similar to those for all sleep disorders combined.

Discussion

The findings are consistent with other studies indicating that sleep disruption is a cancer risk factor. Optimal sleep and appropriate sleep disorder management are modifiable risk factors that may facilitate cancer prevention.

Prediction of adverse events risk in patients with comorbid post-traumatic stress disorder and alcohol use disorder using electronic medical records by deep learning models

BACKGROUND

Identifying co-occurring mental disorders and elevated risk is vital for optimization of healthcare processes. In this study, we will use DeepBiomarker2, an updated version of our deep learning model to predict the adverse events among patients with comorbid post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD), a high-risk population.

METHODS

We analyzed electronic medical records of 5565 patients from University of Pittsburgh Medical Center to predict adverse events (opioid use disorder, suicide related events, depression, and death) within 3 months at any encounter after the diagnosis of PTSD+AUD by using DeepBiomarker2. We integrated multimodal information including: lab tests, medications, co-morbidities, individual and neighborhood level social determinants of health (SDoH), psychotherapy and veteran data.

RESULTS

DeepBiomarker2 achieved an area under the receiver operator curve (AUROC) of 0.94 on the prediction of adverse events among those PTSD+AUD patients. Medications such as vilazodone, dronabinol, tenofovir, suvorexant, modafinil, and lamivudine showed potential for risk reduction. SDoH parameters such as cognitive behavioral therapy and trauma focused psychotherapy lowered risk while active veteran status, income segregation, limited access to parks and greenery, low Gini index, limited English-speaking capacity, and younger patients increased risk.

CONCLUSIONS

Our improved version of DeepBiomarker2 demonstrated its capability of predicting multiple adverse event risk with high accuracy and identifying potential risk and beneficial factors.

Synthesis and Characterization of a New Carbon-11 Labeled Positron Emission Tomography Radiotracer for Orexin 2 Receptors Neuroimaging

Purpose

Orexin receptors (OXRs) play a crucial role in modulating various physiological and neuropsychiatric functions within the central nervous system (CNS). Despite their significance, the precise role of OXRs in the brain remains elusive. Positron emission tomography (PET) imaging is instrumental in unraveling CNS functions, and the development of specific PET tracers for OXRs is a current research focus.

Methods

The study investigated MDK-5220, an OX2R-selective agonist with promising binding properties (EC50 on OX2R: 0.023 μM, Ki on hOX2R: 0.14 μM). Synthesized and characterized as an OX2R PET probe, [11C]MDK-5220 was evaluated for its potential as a tracer. Biodistribution studies in mice were conducted to assess OX2R binding selectivity, with particular attention to its interaction with P-glycoprotein (P-gp) on the blood-brain barrier.

Results

[11C]MDK-5220 exhibited promising attributes as an OX2R PET probe, demonstrating robust OX2R binding selectivity in biodistribution studies. However, an observed interaction with P-gp impacted its brain uptake. Despite this limitation, [11C]MDK-5220 presents itself as a potential candidate for further development.

Discussion

The study provides insights into the functionality of the OX system and the potential of [11C]MDK-5220 as an OX2R PET probe. The observed interaction with P-gp highlights a consideration for future modifications to enhance brain uptake. The findings pave the way for innovative tracer development and propel ongoing research on OX systems, contributing to a deeper understanding of their role in the CNS.

Conclusion

[11C]MDK-5220 emerges as a promising OX2R PET probe, despite challenges related to P-gp interaction. This study lays the foundation for further exploration and development of PET probes targeting OXRs, opening avenues for advancing our understanding of OX system functionality within the brain.

Investigating the Role of BDNF in Insomnia: Current Insights

Insomnia is a common disorder defined as frequent and persistent difficulty initiating, maintaining, or going back to sleep. A hallmark symptom of this condition is a sense of nonrestorative sleep. It is frequently associated with other psychiatric disorders, such as depression, as well as somatic ones, including immunomediated diseases. BDNF is a neurotrophin primarily responsible for synaptic plasticity and proper functioning of neurons. Due to its role in the central nervous system, it might be connected to insomnia of multiple levels, from predisposing traits (neuroticism, genetic/epigenetic factors, etc.) through its influence on different modes of neurotransmission (histaminergic and GABAergic in particular), maintenance of circadian rhythm, and sleep architecture, and changes occurring in the course of mood disturbances, substance abuse, or dementia. Extensive and interdisciplinary evaluation of the role of BDNF could aid in charting new areas for research and further elucidate the molecular background of sleep disorder. In this review, we summarize knowledge on the role of BDNF in insomnia with a focus on currently relevant studies and discuss their implications for future projects.

Prediction of Adverse Events Risk in Patients with Comorbid Post- Traumatic Stress Disorder and Alcohol Use Disorder Using Electronic Medical Records by Deep Learning Models

Background

Prediction of high-risk events in mental disorder patients is crucial. In our previous study, we developed a deep learning model: DeepBiomarker by using electronic medical records (EMR) to predict suicide related event (SRE) risk in post-traumatic stress disorder (PTSD) patients.

Methods

We applied DeepBiomarker2 through data integration of multimodal information: lab test, medication, co-morbidities, and social determinants of health. We analyzed EMRs of 5,565 patients from University of Pittsburgh Medical Center with a diagnosis of PTSD and alcohol use disorder (AUD) on risk of developing an adverse event (opioid use disorder, SREs, depression and death).

Results

DeepBiomarker2 predicted whether a PTSD + AUD patient will have a diagnosis of any adverse events (SREs, opioid use disorder, depression, death) within 3 months with area under the receiver operator curve (AUROC) of 0.94. We found piroxicam, vilazodone, dronabinol, tenofovir, suvorexant, empagliflozin, famciclovir, veramyst, amantadine, sulfasalazine, and lamivudine to have potential to reduce risk.

Conclusions

DeepBiomarker2 can predict multiple adverse event risk with high accuracy and identify potential risk and beneficial factors. Our results offer suggestions for personalized interventions in a variety of clinical and diverse populations.

Pharmacological management of co-morbid obstructive sleep apnoea and insomnia

INTRODUCTION

Clinical presentation of both insomnia and obstructive sleep apnea (COMISA) is common. Approximately 30% of clinical cohorts with OSA have insomnia symptoms and vice versa. The underlying pathophysiology of COMISA is multifactorial. This poses a complex clinical challenge. Currently, there are no clinical guidelines or recommendations outside of continuous positive airway pressure (CPAP) therapy and cognitive behavioral therapy for insomnia (CBTi). Clinically translatable precision medicine approaches to characterize individual causes or endotypes may help optimize future pharmacological management of COMISA.

AREAS COVERED

This review article provides an up-to-date account of COMISA and its consequences, the underlying pathophysiology of sleep apnea, insomnia and COMISA, current treatment approaches and limitations, pharmacotherapy targets and future priorities.

EXPERT OPINION

There are multiple promising emerging therapies, but clinical trial data specifically in COMISA populations are lacking. This is a priority for future investigation to inform development of evidence-based guidelines. Pharmacotherapies, particularly for insomnia, do not target the underlying causes of the disorder thus, are indicated for short-term use only and should remain second line. Future multidisciplinary research should be directed toward the multifactorial nature of COMISA and the challenges of adapting COMISA treatment in clinical practice and overcoming the practical barriers that health-care providers and consumers encounter.

Rethinking the Role of Orexin in the Regulation of REM Sleep and Appetite

Orexin plays a significant role in the modulation of REM sleep, as well as in the regulation of appetite and feeding. This review explores, first, the current evidence on the role of orexin in the modulation of sleep and wakefulness and highlights that orexin should be considered essentially as a neurotransmitter inhibiting REM sleep and, to a much lesser extent, a wake promoting agent. Subsequently, the relationship between orexin, REM sleep, and appetite regulation is examined in detail, shedding light on their interconnected nature in both physiological conditions and diseases (such as narcolepsy, sleep-related eating disorder, idiopathic hypersomnia, and night eating syndrome). Understanding the intricate relationship between orexin, REM sleep, and appetite regulation is vital for unraveling the complex mechanisms underlying sleep-wake patterns and metabolic control. Further research in this field is encouraged in order to pave the way for novel therapeutic approaches to sleep disorders and metabolic conditions associated with orexin dysregulation.

Special Issue "Sleep Disorders: From Clinical Research to Daily Practice"

Healthy sleep is indissolubly linked to both physical and mental health, as pointed out by evidence showing the negative impact of poor sleep on neurological, psychiatric, cardiovascular, respiratory, metabolic, and immune systems, among others [...].