Magnetic Resonance Spectroscopy in the Ventral Tegmental Area Distinguishes Responders to Suvorexant Prior to Treatment: A 4-Week Prospective Cohort Study

Orexin receptor antagonists in the treatment of insomnia associated with psychiatric disorders: a systematic review

Insomnia is highly comorbid in patients with psychiatric disorders, including depression, bipolar disorder, and substance use disorders, and should be treated as an independent condition. Dual orexin receptor antagonists (DORAs) have been investigated as a treatment for chronic insomnia. The objective of this systematic review was to examine evidence for two DORAs, lemborexant and suvorexant, as treatments for insomnia comorbid with a psychiatric disorder. We searched PubMed, Cochrane, and Embase from their inception until January and April 2023, and included studies examining suvorexant and lemborexant for treating insomnia comorbid with psychiatric disorders. We also manually searched clinical trial registries ( https://clinicaltrials.gov and https://www.umin.ac.jp/ctr ). Randomized clinical trials and observational/cohort studies were included. We identified 18 studies from PubMed, Cochrane, and Embase and three studies from clinicaltrials.gov and UMIN. Of the 21 reports, four were completed/terminated randomized clinical trials, eight were ongoing clinical trials, and nine were observational studies. We identified evidence for switching from benzodiazepine receptor agonists to a DORA, or using a DORA as add-on therapy and, therefore, discuss this topic as well. Two studies examined switching to or adding on a DORA in patients being treated with a benzodiazepine receptor agonist. DORAs may be as effective and safe for treating psychiatric comorbid insomnia (for most psychiatric conditions) as they are for treating primary insomnia. However, the evidence is limited to a few small studies. Further investigation of DORAs for the treatment of comorbid insomnia in those with coexisting psychiatric conditions is warranted.

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

After a detailed description of orexins and their roles in sleep and other medical disorders, we discuss here the current clinical evidence on the effects of dual (DORAs) or selective (SORAs) orexin receptor antagonists on insomnia with the aim to provide recommendations for their further assessment in a context of personalized and precision medicine. In the last decade, many trials have been conducted with orexin receptor antagonists, which represent an innovative and valid therapeutic option based on the multiple mechanisms of action of orexins on different biological circuits, both centrally and peripherally, and their role in a wide range of medical conditions which are often associated with insomnia. A very interesting aspect of this new category of drugs is that they have limited abuse liability and their discontinuation does not seem associated with significant rebound effects. Further studies on the efficacy of DORAs are required, especially on children and adolescents and in particular conditions, such as menopause. Which DORA is most suitable for each patient, based on comorbidities and/or concomitant treatments, should be the focus of further careful research. On the contrary, studies on SORAs, some of which seem to be appropriate also in insomnia in patients with psychiatric diseases, are still at an early stage and, therefore, do not allow to draw definite conclusions.

Low Tissue Creatine: A Therapeutic Target in Clinical Nutrition

Low tissue creatine characterizes many conditions, including neurodegenerative, cardiopulmonary, and metabolic diseases, with a magnitude of creatine shortfall often corresponds well to a disorder’s severity. A non-invasive monitoring of tissue metabolism with magnetic resonance spectroscopy (MRS) might be a feasible tool to evaluate suboptimal levels of creatine for both predictive, diagnostic, and therapeutic purposes. This mini review paper summarizes disorders with deficient creatine levels and provides arguments for assessing and employing tissue creatine as a relevant target in clinical nutrition.