Characteristics and clinical correlates of restless legs syndrome in schizophrenia

Restless Legs Syndrome and the Use of Antipsychotic Medication: An Updated Literature Review

Restless legs syndrome or Willis-Ekbom disease (RLS/WED) is a sleep-related movement disorder characterized by an urge to move the legs. This impulse is usually accompanied by an uncomfortable and unpleasant sensation in the legs, which worsens at night and during periods of inactivity and is relieved by movement. Several studies in the literature reported the association between RLS and different antipsychotic medications. with Olanzapine, Quetiapine, and Clozapine identified as the most common causes. The literature suggests that the development of RLS in antipsychotic users may be attributed to the inhibition of dopaminergic neurotransmission or the impact of antipsychotics on iron metabolism. Diagnosing antipsychotic-induced RLS remains a substantial challenge in clinical practice, with challenges in the management of this condition also being widely reported in the current literature. In this article, we will review the evidence suggesting the association between RLS and the use of antipsychotic medications, differentiate between RLS and other movement disorders, and give a brief review of the pathophysiology, diagnosis, and management of RLS and its challenges among psychotic patients.

A Polysomnographic and Cluster Analysis of Periodic Limb Movements in Sleep of Restless Legs Syndrome Patients with Psychiatric Conditions

Only survey studies have linked specific individual psychiatric disorders such as anxiety, depression and schizophrenia to Restless Legs Syndrome (RLS), Periodic Limb Movements in Sleep (PLMS) or both. We therefore aim to polysomnographically characterize sleep in a sample of physician-based, newly diagnosed cases of RLS with various ICD-10 psychiatric diagnoses. Retrospective analysis of data from a convenience sample of psychiatric patients (n = 43) per standard clinical sleep disorder cut-offs was conducted. Next, a cluster analysis was performed on the sleep data, taking into account the psychiatric diagnosis, comorbid non-psychiatric somatic problems and medication. We found that 37.2% of our sample showed clinically significant PLMS ≥ 15 and 76.5% exhibited an apnea hypopnea index (AHI) ≥ 5. Sleep structure was unaltered apart from the PLMS-related parameters. Two clusters were statistically identified: Cluster 1 primarily representing recurrent major depressive issues and Cluster 2 representing present but not predominant mood symptomatology as well as mixed disorders with personality problems. The known confounders were controlled. A PLMS index ≥ 15 was differentially distributed among the two clusters with Cluster 1: 10 out of 17 with PLMS index ≥ 15; Cluster 2: 1 out of 16 with PLMS index ≥15; whilst AHI was not different. Patients in Cluster 1 have a higher rate of periodic leg movements than patients in Cluster 2. This suggests that the high association with PLMS is primarily driven by affective disorders. Our findings warrant questioning of RLS symptomatology in patients with psychiatric conditions.

Association of Premenopausal Bilateral Oophorectomy With Restless Legs Syndrome

IMPORTANCE

Restless legs syndrome is a common neurologic disorder that is more prevalent in women than in men, and it has been suggested that female hormones may be involved in the disorder's pathophysiology.

OBJECTIVE

To determine whether women who underwent premenopausal bilateral oophorectomy were at increased risk of restless legs syndrome.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was performed using data from the Mayo Clinic Cohort Study of Oophorectomy and Aging-2 for a population in Olmsted County, Minnesota. There were 1653 women who underwent premenopausal bilateral oophorectomy before the age of 50 years for a benign indication between 1988 and 2007 and 1653 age-matched women (of same age plus or minus 1 year) in a reference group. Follow-up was conducted until the end of the study period (ie, December 31, 2014). Data were analyzed from January to July 2020.

EXPOSURES

Undergoing bilateral oophorectomy, as shown in medical record documentation.

MAIN OUTCOMES AND MEASURES

Diagnosis of restless legs syndrome, as defined using Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria, was recorded.

RESULTS

Among 3306 women, the median (interquartile range) age at baseline was 44.0 (40.0-47.0) years. Women who underwent bilateral oophorectomy, compared with women who did not undergo this procedure, had a greater number of chronic conditions at the index date (eg, 300 women [18.1%] vs 171 women [10.3%] with ≥3 chronic conditions; overall P < .001), were more likely to have obesity (576 women [34.8%] vs 442 women [27.1%]; overall P < .001), and were more likely to have a history of anemia of any type (573 women [34.7%] vs 225 women [13.6%]; P < .001), iron deficiency anemia (347 women [21.0%] vs 135 women [8.2%]; P < .001), and restless legs syndrome before the index date (32 women [1.9%] vs 14 women [0.8%]; P = .008). Women who underwent bilateral oophorectomy prior to natural menopause had a higher risk of restless legs syndrome after the index date compared with women in the reference group (120 diagnoses vs 74 diagnoses), with an adjusted hazard ratio (HR) of 1.44 (95% CI, 1.08-1.92; P = .01). After stratification by indication for the bilateral oophorectomy, there was an increased risk of restless legs syndrome among women without a benign ovarian condition (HR, 1.52; 95% CI, 1.03-2.25; P = .04) but not among women with a benign condition (HR, 1.25; 95% CI, 0.80-1.96; P = .34). Treatment with estrogen therapy through the age of 46 years in women who underwent bilateral oophorectomy at younger ages was not associated with a difference in risk.

CONCLUSIONS AND RELEVANCE

This cohort study found that risk of restless legs syndrome was increased among women who underwent bilateral oophorectomy prior to menopause, especially those without a benign ovarian indication.

A review of sleep research in patients with spinal cord injury

Study design: Systematic review. Objectives: Sleep disturbances are a common complaint among individuals with spinal cord injury (SCI) and were not usually present before the SCI. Their sleep disturbances, including disrupted sleep, spasms, and problems with initiating and sustaining sleep through the night, affect SCI individuals' overall quality of life due to excessive tiredness and low energy levels during the day. Despite the high prevalence of sleep complaints in this population, current knowledge about sleep in the SCI population has not been systematically assessed. Setting: Capital Region of Denmark. Methods: We systematically reviewed literature identified from the PubMed and EMBASE databases following PRISMA guidelines.Thirty-seven articles met our inclusion criteria, as only controlled studies were included. This could be a comparison of (1) SCI individuals and able-bodied controls, (2) cervical with thoracolumbar SCI individuals, or (3) cervical, thoracolumbar SCI individuals and able-bodied controls. Results: Individuals with SCI have a higher prevalence of sleep-disordered breathing and periodic leg movements during sleep (PLMS), lower heart rate, but no nocturnal lowering of blood pressure. 24-hour energy expenditure and sleeping metabolic rate were significantly lower, and bowel movements were altered. Endocrine alterations were found in investigations of melatonin, cortisol and antidiuretic hormone. Questionnaires revealed a high prevalence of subjectively poorer sleep quality in individuals with SCI compared with able-bodied controls. Conclusions: There are significant differences between groups with SCI and able-bodied controls. SCI objectively and subjectively markedly affects an individual's sleep.

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.

Alterations in sleep, sleep spindle, and EEG power in mGluR5 knockout mice

The type 5 metabotropic glutamate receptor (mGluR5) represents a novel therapeutic target for schizophrenia and other disorders. Schizophrenia is associated with progressive abnormalities in cortical oscillatory processes including reduced spindles (8-15 Hz) during sleep and increased delta (0.5-4 Hz)- and gamma-band activity (30-80 Hz) during wakefulness. mGluR5 knockout (KO) mice demonstrate many schizophrenia-like behaviors, including abnormal sleep. To examine the effects of mGluR5 on the maintenance of the neocortical circuitry responsible for such neural oscillations, we analyzed sleep/wake electroencephalographic (EEG) activity of mGluR5 KO mice at baseline, after 6 h of sleep deprivation, and during a visual method of cortical entrainment (visual steady state response). We hypothesized mGluR5-KO mice would exhibit translationally relevant abnormalities in sleep and neural oscillations that mimic schizophrenia. Power spectral and spindle density analyses were performed across 24-h EEG recordings in mGluR5-KO mice and wild-type (WT) controls. Novel findings in mGluR5 KO mice include deficits in sleep spindle density, wake alpha power, and 40-Hz visual task-evoked gamma power and phase locking. Sigma power (10-15 Hz), an approximation of spindle activity, was also reduced during non-rapid eye movement sleep transitions. Our observations on abnormal sleep/wake are generally in agreement with previous reports, although we did not replicate changes in rapid eye movement sleep. The timing of these phenotypes may suggest an impaired circadian process in mGluR5 KO mice. In conclusion, EEG phenotypes in mGluR5 KO mice resemble deficits observed in patients with schizophrenia. These findings implicate mGluR5-mediated pathways in several translationally relevant phenotypes associated with schizophrenia, and suggest that agents targeting this receptor may have harmful consequences on sleep health and daily patterns of EEG power.NEW & NOTEWORTHY Metabotropic glutamate receptor type 5 (mGluR5) knockout (KO) mice show several translationally relevant abnormalities in neural oscillatory activity associated with schizophrenia. These include deficits in sleep spindle density, sigma and alpha power, and 40-Hz task-evoked gamma power. The timing of these phenotypes suggests an impaired circadian process in these mice. Previously reported rapid eye movement sleep deficits in this model were not observed. These findings suggest mGluR5-enhancing drugs may improve sleep stability and sleep spindle density, which could impact memory and cognition.

Restless arms syndrome: prevalence, impact, and management strategies

This literature review focuses on restless arms syndrome (RAS), an upper limb variant of restless legs syndrome (RLS). RLS, also known as Willis-Ekbom disease, is a frequently occurring neurological disorder characterized by an irresistible urge to move the lower limbs often accompanied by unpleasant sensations in the legs, worsened at rest and in the evening, improved by movement. Extension of leg restlessness to the upper limbs is frequently reported in typical patients who had RLS only in the legs and usually occurs later in the course of RLS, restlessness remaining most invalidating in the lower limbs. In RAS, the arms are predominantly affected with little or no involvement of the legs. Cases of restless shoulders syndrome or periodic arm movements without arm restlessness were not considered. A total of 9 articles with 10 cases were included and analyzed for the adherence to the five essential diagnostic criteria of the International RLS Study Group (IRLSSG) classification, as well as for the additional supportive features. All of the reported cases were classified as having definite RAS. The clinical history and disease evolution of two previously reported patients were completed and updated. Overall, the clinical picture of RAS does not differ from that of RLS, except for the symptoms localization on the upper limbs. Underlying mechanisms of the spread of RLS to upper limb restlessness and of RAS remain unknown. Whether RAS is a phenotypic variant of RLS or a separate entity needs further investigations. RAS likely remains underdiagnosed and according to IRLSSG diagnostic criteria RAS should be considered when RLS-like symptoms are present in one or both arms, especially when they have a circadian pattern and are improved by movement and dopaminergic therapy. Clinicians should be aware of this rare condition, especially as treatment using dopaminergic agonists proves to be very efficient.

Haplotype Association of the MAP2K5 Gene with Antipsychotics-Induced Symptoms of Restless Legs Syndrome among Patients with Schizophrenia

OBJECTIVE

Restless legs syndrome (RLS) is considered a genetic disease and, following a genome-wide association study conducted in 2007, the mitogen-activated protein kinase 5 (MAP2K5) gene has been regarded as the promising candidate gene for RLS. The present study investigated whether polymorphisms of MAP2K5 are associated with antipsychotics-induced RLS in schizophrenia.

METHODS

We assessed antipsychotics-induced RLS symptoms in 190 Korean schizophrenic patients using the diagnostic criteria of the International Restless Legs Syndrome Study Group. Five single-nucleotide polymorphisms (SNPs) of MAP2K5 were genotyped. We investigated genetic and haplotypic associations of these five SNPs with the risk of antipsychotics-induced RLS symptoms.

RESULTS

We divided the 190 subjects into 2 groups: 1) those with RLS symptoms (n=96) and 2) those without RLS symptoms (n=94). There were no significant intergroup differences in the distributions of the genotypes and alleles of the rs1026732, rs11635424, rs12593813, rs4489954, and rs3784709 SNPs. However, the haplotype analysis showed that the G-G-G-G-T (rs1026732-rs11635424-rs12593813-rs4489954-rs3784709) haplotype was associated with RLS symptoms (permutation p=0.033).

CONCLUSION

These data suggest that a haplotype of MAP2K5 polymorphisms confers increased susceptibility to antipsychotics-induced RLS symptoms in schizophrenic patients.

Schizophrenia and sleep disorders: links, risks, and management challenges

Schizophrenia is a major psychiatric disorder that has a massive, long-lasting negative impact on the patients as well as society. While positive symptoms (i.e., delusions and hallucinations), negative symptoms (i.e., anhedonia, social withdrawal), and cognitive impairments are traditionally considered the most prominent features of this disorder, the role of sleep and sleep disturbances has gained increasing prominence in clinical practice. Indeed, the vast majority of patients with schizophrenia report sleep abnormalities, which tend to precede illness onset and can predict an acute exacerbation of psychotic symptoms. Furthermore, schizophrenia patients often have a comorbid sleep disorder, including insomnia, obstructive sleep apnea, restless leg syndrome, or periodic limb movement disorder. Despite accumulating data, the links between sleep disorders and schizophrenia have not been thoroughly examined, in part because they are difficult to disentangle, as numerous factors contribute to their comorbidity, including medication status. Additionally, sleep disorders are often not the primary focus of clinicians treating this population, despite studies suggesting that comorbid sleep disorders carry their own unique risks, including worsening of psychotic symptoms and poorer quality of life. There is also limited information about effective management strategies for schizophrenia patients affected by significant sleep disturbances and/or sleep disorders. To begin addressing these issues, the present review will systematically examine the literature on sleep disorders and schizophrenia, focusing on studies related to 1) links between distinct sleep disorders and schizophrenia; 2) risks unique to patients with a comorbid sleep disorder; and 3) and management challenges and strategies.

Gabapentin treatment in clozapine-induced restless legs syndrome: two cases and a review of the literature

Restless legs syndrome (RLS) is a neuro-sensorimotor disorder affecting 2-4% of adults. It is characterized by intense urges to move the legs, associated with unpleasant sensory disturbances in the legs occurring at rest and manifests mostly in the evening and night, relieved by movement. Diagnosis is primarily based on clinical presentation and the consensus criteria for the diagnosis have been established. Antipsychotics, the dopamine antagonists, have been reported to induce RLS. Dopamine agonists, the effective first-line treatment of RLS, carry the risk of inducing or worsening psychosis. Many nondopaminergic agents including antiepileptic medications have also been used in the treatment of primary RLS. In this report we describe clozapine-induced RLS in two patients with schizophrenia and its successful treatment with gabapentin, a nondopaminergic agent. In addition, we have reviewed the available literature on clozapine-induced RLS and its management.

Akathisia: prevalence and risk factors in a community-dwelling sample of patients with schizophrenia. Results from the FACE-SZ dataset

The main objective of this study was to determine the prevalence of akathisia in a community-dwelling sample of patients with schizophrenia, and to determine the effects of treatments and the clinical variables associated with akathisia. 372 patients with schizophrenia or schizoaffective disorder were systematically included in the network of FondaMental Expert Center for Schizophrenia and assessed with validated scales. Akathisia was measured with the Barnes Akathisia Scale (BAS). Ongoing psychotropic treatment was recorded. The global prevalence of akathisia (as defined by a score of 2 or more on the global akathisia subscale of the BAS) in our sample was 18.5%. Patients who received antipsychotic polytherapy were at higher risk of akathisia and this result remained significant (adjusted odd ratio=2.04, p=.025) after controlling the influence of age, gender, level of education, level of psychotic symptoms, substance use comorbidities, current administration of antidepressant, anticholinergic drugs, benzodiazepines, and daily-administered antipsychotic dose. The combination of second-generation antipsychotics was associated with a 3-fold risk of akathisia compared to second-generation antipsychotics used in monotherapy. Our results indicate that antipsychotic polytherapy should be at best avoided and suggest that monotherapy should be recommended in cases of akathisia. Long-term administration of benzodiazepines or anticholinergic drugs does not seem to be advisable in cases of akathisia, given the potential side effects of these medications.

Sleep Disorders Among People With Schizophrenia: Emerging Research

Up to 80 % of individuals with schizophrenia spectrum disorders experience sleep disturbances, which impact physical and mental health, as well as quality of life. In this paper, we review and integrate emerging literature, published between 2012 and 2014, regarding approaches to diagnosis and treatment of major sleep disorders for people with schizophrenia spectrum disorders, including insomnia, obstructive sleep apnea (OSA), circadian rhythm dysfunction, and restless legs syndrome (RLS). We advocate for (1) the need to evaluate the utility of nonpharmacological approaches in people with schizophrenia spectrum disorders; (2) documentation of guidelines to assist providers in clinically tailoring such interventions when their clients experience positive, negative, and/or cognitive symptoms; (3) research on the best ways providers can capitalize on clients' self-identified needs and motivation to engage in sleep treatments through shared decision making; and (4) the importance of investigating whether and how mental health and sleep treatment services should be better connected to facilitate access for people with schizophrenia spectrum disorders. Assessment and tailored treatment of sleep disorders within mental health treatment settings has the potential to reduce sleep problems and improve functioning, quality of life, and recovery of this population.

MEIS1, a Promising Candidate Gene, Is Not Associated with the Core Symptoms of Antipsychotic-Induced Restless Legs Syndrome in Korean Schizophrenia Patients

OBJECTIVE

Restless legs syndrome (RLS) is a distressing sleep disorder to which individuals appear to be genetically predisposed. In the present study, we assumed that antipsychotic-induced RLS symptoms were attributable to differences in individual genetic susceptibility, and investigated whether MEIS1, a promising candidate gene, was associated with antipsychotic-induced RLS symptoms in schizophrenia patients.

METHODS

All subjects were diagnosed with schizophrenia by board-certified psychiatrists using the Korean version of the Structured Clinical Interview for DSM-IV. We assessed antipsychotic-induced RLS symptoms in 190 Korean schizophrenic patients using the diagnostic criteria of the International Restless Legs Syndrome Study Group. Genotyping was performed for the rs2300478 and rs6710341 polymorphisms of the MEIS1 gene.

RESULTS

We divided subjects into RLS symptom (n=96) and non-symptom (n=94) groups. There was no significant between-group difference in the genotype or allele frequencies of the two polymorphisms investigated, nor in the frequency of the rs2300478-rs6710341 haplotype.

CONCLUSION

Our data do not suggest that the rs2300478 and rs6710341 polymorphisms of the MEIS1 gene are associated with the core symptoms of antipsychotic-induced RLS in schizophrenia; different genetic mechanisms may underlie antipsychotic-induced vs. primary RLS.

Association between restless legs syndrome and CLOCK and NPAS2 gene polymorphisms in schizophrenia

Previous studies have suggested that there is a genetic basis to restless legs syndrome (RLS) development. Occurrence of antipsychotic-induced RLS could also be due to differences in genetic susceptibility. We investigated whether CLOCK and NPAS2 gene polymorphisms are associated with RLS in schizophrenic patients on antipsychotics because RLS symptoms usually manifest during the evening and night. We assessed symptoms of RLS in 190 Korean schizophrenic patients on antipsychotics and divided the subjects into two groups according to the International Restless Legs Syndrome Study Group diagnostic criteria: (i) subjects who met all the criteria and (ii) the remaining subjects who did not meet all the criteria. We found a significant difference in the number of subjects with different genotype and allele carrier frequencies for the CLOCK gene (rs2412646) between the two groups (p = 0.031 and 0.010, respectively). Distribution of CLOCK haplotypes (rs2412646-rs1801260) was significantly different between schizophrenic patients with and without RLS (p = 0.021). However, the distributions of allelic, genotypic, and haplotypic variants of NPAS2 (rs2305160 and rs6725296) were not significantly different between the two groups. Our results suggest that CLOCK polymorphisms are associated with increased susceptibility of schizophrenic patients to RLS. We hypothesize that RLS in schizophrenia patients treated with antipsychotics may be a very mild akathisia that manifests during the night and is under control of circadian oscillation.

Treatment adherence and quality of sleep in schizophrenia outpatients

OBJECTIVE

Patients with schizophrenia (SZ) often present sleep complaints, and patients with sleep disturbances are at a greater risk for symptom worsening after antipsychotic discontinuation. Long-term adherence to antipsychotic treatment remains a challenge for clinicians, and the relationship between quality of sleep and treatment adherence in SZ outpatients has been poorly studied.

METHODS

In this cross-sectional, non-interventional study, 811 adult outpatients with a diagnosis of SZ were divided into two groups according to the presence (or absence) of sleep disturbances, and assessed using measures of symptom severity, quality and patterns of sleep, adherence/compliance to treatment, and family support degree.

RESULTS

Patients with sleep disturbances were significantly more symptomatic (p < 0.0001), and scored significantly higher on the Pittsburgh Sleep Quality Index (PSQI) as compared with patients without sleep disturbances (p < 0.0001). More compliant patients showed less sleep disturbances (p < 0.0001); moreover, patients with worse compliance to pharmacological treatment showed significantly higher scores on the PSQI (p < 0.0001). Regarding family support degree, patients with sleep disorders presented a lower family support (p = 0.0236), and patients with worse treatment adherence had worse family support (p < 0.0001).

CONCLUSIONS

Our findings show that SZ outpatients reporting sleep disturbances show greater symptom severity, and worse adherence/compliance to treatment, as well as a lower family support.

Treatment of restless legs syndrome

OPINION STATEMENT

Restless legs syndrome (RLS) is a common, sensorimotor, circadian sleep disorder characterized by the urge to move the legs, particularly at nighttime. It is important to differentiate primary and secondary RLS from other conditions, which can mimic the symptoms of RLS, in particular neuropathy and cramps. Despite considerable advances, the understanding of RLS pathophysiology remains incomplete. Many hypotheses focus on central nervous system structures, although there is increasing evidence that peripheral structures may also be important. There is insufficient evidence at the moment to recommend changes in lifestyle, nutritional supplements and any specific nonpharmacologic treatments. The first-line drugs continue to be dopaminergic medications, including pramipexole, ropinirole, rotigotine transdermal patch and levodopa. However, the phenomenon of RLS augmentation, a paradoxical worsening of symptoms by dopaminergic treatment remains as major problem in treatment of RLS, and prevention of augmentation is one of the main goals in the management of RLS. RLS requires treatment only if it has a significant impact on the patient's nighttime sleep or daily activities. Doses of dopamine agonists should be kept to the minimum required for acceptable symptom reduction. Augmentation may require treatment withdrawal, with prescription of alternate medication. Alternative or additional pharmacologic treatment with a lower level of overall quality of evidence includes opioids (codeine, tramadol, and oxycodone) and anticonvulsants (gabapentin, gabapentin enacarbil, and pregabalin). The choice of the medication should be based on the severity of RLS and the effectiveness of medication for the short-term or long-term treatment of RLS. Iron deficiency must be identified at diagnosis; treatment may improve RLS symptoms and potentially may lower risk of augmentation. There is no clear evidence for treatment of secondary RLS, but agents used in primary RLS should be tried. Comparative long-term trials are required to assess differences in efficacy and augmentation rates between medications used for treatment of RLS.

The BTBD9 gene may be associated with antipsychotic-induced restless legs syndrome in schizophrenia

OBJECTIVE

A genome-wide association study and several replication studies have shown significant association between BTBD9 gene single nucleotide polymorphisms and restless legs syndrome (RLS). The aim of this study is to investigate the association between the BTBD9 gene polymorphisms and antipsychotic-induced RLS in schizophrenic patients.

METHODS

Restless legs syndrome symptoms were evaluated using the diagnostic criteria of the International Restless Legs Syndrome Study Group in 190 Korean schizophrenic patients. We genotyped the rs9357271 and rs3923809 polymorphisms of the BTBD9 gene in schizophrenic patients with (n = 96) and without (n = 94) RLS symptoms.

RESULTS

There was a significant difference in the allele frequency (χ(2) = 8.14, p = 0.004) of the rs9357271 polymorphism between schizophrenic patients with and without RLS symptoms. Significant genotypic association of this single nucleotide polymorphisms with RLS symptoms was also observed for the dominant model (χ(2) = 10.32, p = 0.001) and heterozygous model (χ(2) = 10.9, p = 0.001). When we compared the frequencies of the rs3923809-rs9357271 haplotypes between the two groups, the overall haplotype frequencies were significantly different (permuted p = 0.037), and the A-T haplotype was significantly more frequent in the RLS symptom group than in the no RLS symptom group (0.112 vs. 0.041, permuted p = 0.007).

CONCLUSIONS

These data suggest that the BTBD9 gene is associated with antipsychotic-induced RLS symptoms in schizophrenic patients.

The psychopharmacological management of RLS in psychiatric conditions: a review of the literature

BACKGROUND

Restless legs syndrome (RLS) is a movement disorder treated with dopamine agonists. RLS is often diagnosed as a comorbid condition with psychiatric disorders, which are treated with dopamine antagonists or antidepressants resulting in onset or exacerbation of RLS symptoms.

OBJECTIVES

The objectives of this article are to provide a review of the literature to (a) describe the comorbidity of psychiatric disorders associated with RLS, (b) identify the treatment of psychiatric disorders that cause or exacerbate symptoms of RLS, and (c) provide clinical recommendations for psychiatric health care providers.

DESIGN

A review of the literature of English articles included the databases of Medline, Pubmed, PsychINFO, and CINAHL for "Restless Legs Syndrome" with major psychiatric disorders including mood disorders (depression and bipolar), schizophrenia, and anxiety disorders (anxiety, panic disorder, obsessive compulsive disorder). The PRISMA guidelines were used to improve the reporting of the review of the literature.

RESULTS

There were 61 articles that met the inclusion and exclusion criteria identified for the review of the literature, including RLS with mood disorders (n = 36), schizophrenia (n = 9), and anxiety disorders (n = 16).

CONCLUSIONS

Clinical trials are lacking on the best treatment for persons with RLS and psychiatric disorders; the most rigorous research found in the literature related to depression and anxiety. Studies lack evidence to document the best practice for persons with RLS and comorbid psychiatric disorders. Psychiatric health care providers should be aware of RLS, which is influenced by psychiatric medications.

If waking and dreaming consciousness became de-differentiated, would schizophrenia result?

If both waking and dreaming consciousness are functional, their de-differentiation would be doubly detrimental. Differentiation between waking and dreaming is achieved through neuromodulation. During dreaming, without external sensory data and with mesolimbic dopaminergic input, hyper-cholinergic input almost totally suppresses the aminergic system. During waking, with sensory gates open, aminergic modulation inhibits cholinergic and mesocortical dopaminergic suppresses mesolimbic. These neuromodulatory systems are reciprocally interactive and self-organizing. As a consequence of neuromodulatory reciprocity, phenomenologically, the self and the world that appear during dreaming differ from those that emerge during waking. As a result of self-organizing, the self and the world in both states are integrated. Some loss of self-organization would precipitate a degree of de-differentiation between waking and dreaming, resulting in a hybrid state which would be expressed heterogeneously, both neurobiologically and phenomenologically. As a consequence of progressive de-differentiation, certain identifiable psychiatric disorders may emerge. Ultimately, schizophrenia, a disorganized-fragmented self, may result.

Periodic limb movements during sleep and restless legs syndrome in patients with ASIA A spinal cord injury

OBJECTIVE

To establish the occurrence of Periodic Leg Movements (PLM) and Restless Legs Syndrome (RLS) in Spinal Cord Injury (SCI) subjects.

METHODS

In this study, twenty four patients were submitted to a full night polysomnography and were assessed with Epworth Sleepiness Scale and an adapted form of International Restless Legs Syndrome Scale Rating Scale (IRLS Rating Scale). Control Group (CG) was composed of 16 subjects, 50% of each sex, age: 24.38±4 years old. Spinal Cord Injury Group (SCIG) was composed of 8 subjects (29±5 years old) with a complete SCI (ASIA A) of about three and a half years of duration, 100% males.

RESULTS

100% of SCIG had RLS compared to 17% in CG (p<0.0001). SCIG had 18.11±20.07 of PLM index while CG had 5.96±11.93 (p=0.01). Arousals related to PLM were recorded in CG and SCIG. There was a positive moderate correlation between RLS and age (r=0.5; p=0.01), RLS and PLM (r=0.49; p=0.01), adapted IRLS Rating Scale and PLM index (r=0.64; p=0.03) and also a negative moderate correlation between Epworth Sleepiness Scale and PLM index (r=-0.4; p=0.04) in both groups.

CONCLUSION

RLS and PLM are common findings in SCI patients with a complete injury.

Association study between antipsychotic-induced restless legs syndrome and polymorphisms of monoamine oxidase genes in schizophrenia

OBJECTIVE

This study aimed to investigate whether the monoamine oxidase (MAO) A and B genes are associated with antipsychotic-induced restless legs syndrome (RLS) in schizophrenia.

METHODS

We assessed antipsychotic-induced RLS symptoms in 190 Korean schizophrenic patients and divided the subjects into two groups: those with RLS symptoms (n = 96) and those without RLS symptoms (n = 94). Genotyping was performed for the variable number of tandem repeat (VNTR) polymorphism of the MAOA gene and A644G polymorphism of the MAOB gene.

RESULTS

There was no significant difference in the genotype and allele frequencies of all polymorphisms investigated between these two groups. However, the result of global haplotype analysis showed a significant difference in haplotype frequencies between male subjects with and without RLS symptoms (p = 0.013). The interaction between two polymorphisms had a significant effect on the RLS scores of both male (p = 0.047) and female (p = 0.028) patients.

CONCLUSIONS

These data do not suggest that the MAOA gene VNTR and MAOB gene A644G polymorphisms are associated with antipsychotic-induced RLS symptoms in schizophrenia. However, we found that the haplotype frequencies differed between the male schizophrenic patients with and without RLS symptom and the interaction between the two polymorphisms had a significant influence on the RLS scores of patients with schizophrenia.

Association between Antipsychotics-Induced Restless Legs Syndrome and Tyrosine Hydroxylase Gene Polymorphism

OBJECTIVE

Restless legs syndrome (RLS) has been reported to be more prevalent in schizophrenic patients who take antipsychotics. The cause of RLS is unknown but associated with dopaminergic deficiency. Tyrosine hydroxylase (TH) is the enzyme responsible for catalyzing the conversion of L-tyrosine to DOPA. The purpose of this study is to determine whether the TH gene Val81Met polymorphism is associated with antipsychotic-induced RLS.

METHODS

One hundred ninety Korean schizophrenic patients were evaluated by the diagnostic criteria of the International RLS Study Group (IRLSSG). The genotyping was performed by PCR-based methods.

RESULTS

Of the one hundred ninety schizophrenic patients, 44 (23.2%) were found to have RLS. Although there were no significant associations between TH genotypes or allele frequencies and RLS, when separate analyses were performed by sex (male or female), we detected significant differences in the frequencies of the genotype (chi(2)=6.15, p=0.046) and allele (chi(2)=4.67, p=0.031) of the TH gene Val81Met polymorphism between those with and without RLS in the female patients.

CONCLUSION

These findings suggest that the TH gene Val81Met SNP might be associated with antipsychotic-induced RLS in female schizophrenic patients.

Restless legs syndrome and periodic limb movements during sleep probably associated with olanzapine

We report five cases of restless legs syndrome (RLS) and periodic limb movements during sleep (PLMS) that were probably associated with olanzapine. The first patient showed a good response to olanzapine, but the RLS symptoms associated with olanzapine resulted in poor long-term compliance, eventually leading to frequent relapse of psychotic symptoms. The second patient exhibited sudden PLMS following olanzapine injection. The third patient had been suffering from serious akathisia while on risperidone, and was cured after switching to olanzapine, but thereafter the patient suffered from RLS at nighttime. The fourth patient showed RLS symptoms that were initially caused by a 20-mg daily olanzapine dosage and were later mitigated when olanzapine was reduced and ropinirole was administered. The fifth patient exhibited paraesthesia and agitation caused by olanzapine that was misdiagnosed as psychotic agitation. Increasing the olanzapine dosage severely aggravated the symptoms of RLS. Antipsychotic-induced RLS and PLMS are not well-recognized side effects of antipsychotics, with the symptoms often misdiagnosed as psychotic agitation. These cases also suggest that the occurrence of RLS can cause noncompliance with antipsychotics in psychiatric patients, and thus aggravate their psychotic symptoms.

Update on sleep and psychiatric disorders

Current data demonstrate a high rate of comorbidity between sleep disorders and various psychiatric illnesses, especially mood and anxiety disorders. The disturbance of sleep quality and continuity that is associated with many sleep disorders predisposes to the development or exacerbation of psychological distress and mental illness. Likewise, the presence of psychiatric illness may complicate the diagnosis and treatment of sleep disorders. This focused review examines the literature concerning the interaction between major International Classification of Sleep Disorders, 2nd edition, diagnoses and psychiatric conditions with respect to sleep findings in various psychiatric conditions, psychiatric comorbidity in sleep disorders, and reciprocal interactions, including treatment effects. The data not only underscore the high frequency of psychopathology and psychological distress in sleep disorders, and vice versa, but also suggest that combined treatment of both the mental disorder and the sleep disorder should become the standard for effective therapy for all patients.

[Restless legs syndrome, periodic limb movements, and psychopharmacology]

Restless legs syndrome (RLS) and the often associated periodic limb movement disorder in sleep (PLMD) frequently occur in the general population as a primary disorder. In addition to organic disease, secondary forms are caused by psychotropic medication. Several antidepressants, antipsychotics, lithium, and opioid withdrawal have been shown to induce or exacerbate RLS and PLMD, while several antiepileptics used as mood stabilizers and some benzodiazepines demonstrate therapeutic potential for treating RLS/PLMD. Systematic or controlled studies for evaluating these side effects still do not exist. Among the antidepressants at higher risk of inducing this disorder are selective serotonin reuptake inhibitors, venlafaxine, and some tetracyclic antidepressants. Under medication with some tricyclic substances, periodic limb movements were observed more often. For some antidepressants with differing transmitter profiles such as bupropion RLS/PLMD ameliorating effects or at least neutral effects (Trazodon, Nortriptylin) have been described in small studies. In case of continued of or newly occurring insomnia a thorough history should be taken to identify a possible RLS/PLMD as an intolerable side effect of treatment. A change in medications should be considered if clinically feasible. In case of RLS/PLMD occurring in psychotic patients switching the antipsychotic and additionally using a second line medication such as antiepileptics or a benzodiazepine should be considered.

Possible association between G-protein β3 subunit C825T polymorphism and antipsychotic-induced restless legs syndrome in schizophrenia

OBJECTIVE

The incidence of restless legs syndrome (RLS) is presumed to be higher among people with schizophrenia who take antipsychotic medication, most of which blocks the dopamine D2 receptor. The purpose of this study was to determine whether the G-protein β3 subunit (GNB3) C825T polymorphism is associated with antipsychotic-induced RLS in schizophrenia.

METHODS

We examined 178 Korean patients with schizophrenia. All of the subjects were evaluated using the diagnostic criteria of the International Restless Legs Syndrome Study Group and the International Restless Legs Scale. Genotyping was performed for the C825T polymorphism in the GNB3 gene.

RESULTS

The genotype distribution did not differ significantly between antipsychotic-induced RLS patients and patients who had no-RLS symptoms (χ 2 = 4.30, p = 0.116). The genotypes of the C825T single-nucleotide polymorphism (SNP) were classified into two groups: C+ (CC and CT genotypes) and C- (TT genotype). The presence of the C allele (C+) was associated with an increased likelihood of RLS (χ 2 = 4.14, p = 0.042; odds ratio = 2.56, 95% confidence interval = 1.02-6.47).

CONCLUSIONS

These results suggest that the GNB3 C825T SNP is associated with RLS in schizophrenia. However, confirming this association requires future larger scale studies in which the effects of medication are strictly controlled.