Willis-Ekbom disease/restless legs syndrome in patients with opioid withdrawal

Restless legs syndrome, neuroleptic-induced akathisia, and opioid-withdrawal restlessness: shared neuronal mechanisms?

Restlessness is a core symptom underlying restless legs syndrome (RLS), neuroleptic-induced akathisia, and opioid withdrawal. These three conditions also share other clinical components suggesting some overlap in their pathophysiology. Recent prospective studies demonstrate the frequent incidence of RLS-like symptoms during opioid withdrawal and supervised prescription opioid tapering. Based on the therapeutic role of µ-opioid receptor (MOR) agonists in the three clinical conditions and recent preclinical experimental data in rodents, we provide a coherent and unifying neurobiological basis for the restlessness observed in these three clinical syndromes and propose a heuristic hypothesis of a key role of the specific striatal neurons that express MORs in akathisia/restlessness.

Prevalence and clinical correlates of restless legs syndrome in psychiatric patients: A cross-sectional study from North India

Background

Restless legs syndrome (RLS) is a neuro-sensorimotor disorder which is scarcely researched and is commonly missed in routine psychiatry practice.

Aim

To evaluate the prevalence of RLS and its correlates in patients with anxiety, depression, and somatoform disorders.

Methods

A cross-sectional single-center study was undertaken in patients aged 18-65 years suffering from ICD-10 (International Statistical Classification of Diseases-10th edition) diagnosis of anxiety, depressive, and somatoform disorders. RLS was evaluated by using diagnostic criteria of International Restless Legs Syndrome Study Group (IRLSSG) and severity measured on IRLSSG scale. Depression and anxiety were rated on Hamilton Depression and Anxiety Rating Scales respectively, insomnia severity measured by Insomnia Severity Index (ISI), and quality of life measured by WHO Quality of Life-Brief version (WHO-QOL BREF) scale. Serum ferritin levels were measured for evaluating iron deficiency.

Results

The rate of RLS was 66.7%, 50%, and 48% in patients with depressive, anxiety, and somatoform disorders, respectively, with no significant inter-group difference. Nearly one-third of patients suffered from severe to very severe symptoms of RLS, and quality of life was poorest in those with depressive disorders. RLS was significantly higher in females (P = 0.019), who were married (P = 0.040), diagnosed with severe depression (P = 0.029), and abused benzodiazepines (P = 0.045). On binary logistic regression, female gender and presence of clinical insomnia predicted occurrence of RLS.

Conclusion

The prevalence of RLS is very high in patients with common psychiatric disorders which is often missed. Clinical enquiry and examination for reversible causes such as iron deficiency may assist in its diagnosis and improve clinical outcome.

Emergence of restless legs syndrome during opioid discontinuation

STUDY OBJECTIVES

The development of restless legs syndrome (RLS) has been rarely reported during and following opioid withdrawal. We aimed to determine the presence and severity of RLS symptoms during and after supervised opioid tapering.

METHODS

Ninety-seven adults enrolled in the Mayo Clinic Pain Rehabilitation Center who underwent supervised prescription opioid tapering were prospectively recruited. RLS presence and severity was assessed with the Cambridge-Hopkins Questionnaire 13 and International Restless Legs Syndrome Study Group Rating Severity Scale at admission, midpoint, and dismissal from the program as well as 2 weeks, 4 weeks, and 3 months after completion. Frequency and severity of RLS symptoms were compared between admission and each time point.

RESULTS

Average age of the cohort was 52.6 ± 13.3 years with a morphine milligram equivalent dose for the cohort of 45.6 ± 48.3 mg. Frequency of RLS symptoms increased from 28% at admission to peak frequency of 41% at 2 weeks following discharge from the Mayo Pain Rehabilitation Clinic (P = .01), returning to near baseline frequency 3 months after opioid discontinuation. International Restless Legs Syndrome Study Group Rating Severity Scale increased from baseline and then remained relatively stable at each time point following admission. Thirty-five (36.1%) participants developed de novo symptoms of RLS during their opioid taper, with those being exposed to higher morphine milligram equivalent doses having higher risk of developing RLS.

CONCLUSIONS

Moderately severe symptoms of RLS, as assessed by survey, occur commonly in individuals undergoing opioid tapering, particularly if exposed to higher doses. In many cases, symptoms appear to be self-limited, although a minority develop persistent symptoms. Our results may have implications for successful opioid tapering, but future confirmatory studies with structured clinician interview are needed to establish that these symptoms truly represent restless legs syndrome given the potential for RLS-mimicking symptoms in individuals with chronic pain syndromes.

CITATION

McCarter SJ, Labott JR, Mazumder MK, et al. Emergence of restless legs syndrome during opioid discontinuation. J Clin Sleep Med. 2023;19(4):741-748.

Metabotropic glutamate receptor function and regulation of sleep-wake cycles

Metabotropic glutamate (mGlu) receptors are the most abundant family of G-protein coupled receptors and are widely expressed throughout the central nervous system (CNS). Alterations in glutamate homeostasis, including dysregulations in mGlu receptor function, have been indicated as key contributors to multiple CNS disorders. Fluctuations in mGlu receptor expression and function also occur across diurnal sleep-wake cycles. Sleep disturbances including insomnia are frequently comorbid with neuropsychiatric, neurodevelopmental, and neurodegenerative conditions. These often precede behavioral symptoms and/or correlate with symptom severity and relapse. Chronic sleep disturbances may also be a consequence of primary symptom progression and can exacerbate neurodegeneration in disorders including Alzheimer's disease (AD). Thus, there is a bidirectional relationship between sleep disturbances and CNS disorders; disrupted sleep may serve as both a cause and a consequence of the disorder. Importantly, comorbid sleep disturbances are rarely a direct target of primary pharmacological treatments for neuropsychiatric disorders even though improving sleep can positively impact other symptom clusters. This chapter details known roles of mGlu receptor subtypes in both sleep-wake regulation and CNS disorders focusing on schizophrenia, major depressive disorder, post-traumatic stress disorder, AD, and substance use disorder (cocaine and opioid). In this chapter, preclinical electrophysiological, genetic, and pharmacological studies are described, and, when possible, human genetic, imaging, and post-mortem studies are also discussed. In addition to reviewing the important relationships between sleep, mGlu receptors, and CNS disorders, this chapter highlights the development of selective mGlu receptor ligands that hold promise for improving both primary symptoms and sleep disturbances.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

Why Are Women Prone to Restless Legs Syndrome?

Restless legs syndrome is a relatively common neurologic disorder considerably more prevalent in women than in men. It is characterized by an inactivity-induced, mostly nocturnal, uncomfortable sensation in the legs and an urge to move them to make the disagreeable sensation disappear. Some known genes contribute to this disorder and the same genes contribute to an overlapping condition—periodic leg movements that occur during sleep and result in insomnia. Dopamine and glutamate transmission in the central nervous system are involved in the pathophysiology, and an iron deficiency has been shown in region-specific areas of the brain. A review of the literature shows that pregnant women are at particular risk and that increased parity is a predisposing factor. Paradoxically, menopause increases the prevalence and severity of symptoms. This implies a complex role for reproductive hormones. It suggests that changes rather than absolute levels of estrogen may be responsible for the initiation of symptoms. Both iron (at relatively low levels in women) and estrogen (at relatively high oscillating levels in women) influence dopamine and glutamate transmission, which may help to explain women’s vulnerability to this condition. The syndrome is comorbid with several disorders (such as migraine, depression, and anxiety) to which women are particularly prone. This implies that the comorbid condition or its treatment, or both, contribute to the much higher prevalence in women than in men of restless legs syndrome.

Evaluation of restless leg syndrome symptoms in patients with lumbosacral canal stenosis comparison with normal population

Introduction: Restless leg syndrome (RLS) is a neurological disorder that causes an irresistible urge to move the legs often associated with an unpleasant sensation. Due to some common presentations between RLS and lumbosacral spinal stenosis, the purpose of this study was to evaluate the symptoms of RLS in the presence of spinal stenosis at the same time as normal populations.Materials and methods: This cross-sectional study examined 45 patients with lumbosacral spinal canal stenosis and 45 normal individuals without a specific disease. Patients aged 50-70 years were included in the study. All the statistical analyses were carried out using SPSS 21.0 software and p < 0.05 was considered statistically significant.Results: 19 subjects (42.22%) in the patient group and eight in the normal group (17.8%) suffered from restless leg syndrome. Multiple linear regression analysis revealed that patients with lumbosacral canal stenosis had almost five score less than others in RLS scale.Conclusion: RLS symptoms were more prominent in lumbosacral canal stenosis patients compared to the normal group. The awareness of its symptoms can help reduce misdiagnosis.