olanzapine and Sleep-Wake-Disorders

Olanzapine is an atypical antipsychotic drug that inhibits serotonergic, dopaminergic, alpha-1 adrenergic, histaminic, and muscarinic receptors. Several phase I and II trials have been published documenting the use of olanzapine in controlling chemotherapy-induced nausea and vomiting (CINV). This review aims to summarize all phase I and II trials that reported on olanzapine for the prophylaxis of CINV.. A literature search was conducted in Ovid MEDLINE from 1946 to July week 1 2015, Embase Classic and Embase from 1947 to 2015 week 28, and the Cochrane Central Register of Controlled Trials up until June 2015. Phase I and II trials reporting on olanzapine for the prophylaxis for CINV were included if they reported on at least one of four primary endpoints: complete response (CR), complete control (CC), no nausea, and no emesis. Other endpoints of interest included the safety of olanzapine as measured by the M.D. Anderson Symptom Inventory.. Across the seven included studies, there were a total of 201 patients. The CR across four studies was 97.2, 83.1, and 82.8 % for the acute, delayed, and overall phases, respectively. The CC for acute, delayed, and overall phases was 92.5, 87.5, and 82.5 %, respectively. The overall no nausea rate was 92.7, 71.8, and 70.6 % for the acute, delayed, and overall phases, respectively. The overall no emesis rates for the acute, delayed, and overall phases were 100, 94.5, and 90.4 %, respectively. Fatigue, drowsiness, and disturbed sleep were common side effects.. Olanzapine is efficacious and safe when used as a prophylaxis for CINV.

Topics: Antiemetics; Antineoplastic Agents; Antipsychotic Agents; Benzodiazepines; Dyssomnias; Fatigue; Humans; Induction Chemotherapy; Male; Middle Aged; Nausea; Olanzapine; Remission Induction; Sleep Wake Disorders; Vomiting

Topics: Aged; Antipsychotic Agents; Aripiprazole; Basal Ganglia Diseases; Benzodiazepines; Clozapine; Diagnosis, Differential; Female; Humans; Metabolic Syndrome; Middle Aged; Olanzapine; Pain; Patient Compliance; Peripheral Nervous System Diseases; Piperazines; Quinolones; Schizophrenia, Paranoid; Skin Diseases, Parasitic; Sleep Wake Disorders

Sleep disorders, such as insomnia and nightmares, are common problems in post-traumatic stress disorder (PTSD), exert a strong negative influence on the quality of life and are a great challenge for clinical psychiatry. Several studies have reported on the efficacy of drugs for the treatment of PTSD-related sleep disorders. These studies have not been systematically reviewed. This is the first review on the effectiveness of sleep medication in PTSD. We performed a Medline, EMBASE and Cochrane Library Indexed search, using the keywords: PTSD, pharmacotherapy, therapy, sleep, nightmares, insomnia and review. From this database, English-language, human subject, data driven papers published after 1980 were selected. Forty eight articles are discussed. Open-label and case studies suggest efficacy for some antidepressants, anticonvulsants and atypical antipsychotics. Only a few placebo-controlled studies have been published. They show promising results for the atypical antipsychotic olanzapine, and the alpha1-adrenoceptor antagonist prazosin. In comparison to the incidence and impact of sleep complaints in PTSD, the pharmacotherapeutic armamentarium for PTSD-related sleep complaints remains poorly investigated. Some recent studies show promising results, especially for alpha1-adrenoceptor and 5-HT2 receptor antagonists. However, randomized controlled trials with larger populations need to be conducted.

Topics: Adrenergic alpha-1 Receptor Antagonists; Anti-Anxiety Agents; Anticonvulsants; Antidepressive Agents; Antipsychotic Agents; Benzodiazepines; Clinical Trials as Topic; Humans; Monoamine Oxidase Inhibitors; Olanzapine; Prazosin; Selective Serotonin Reuptake Inhibitors; Sleep Wake Disorders; Stress Disorders, Post-Traumatic

Adverse effects of antipsychotics often lead to noncompliance. Thus, clinicians should address patients' concerns about adverse effects and attempt to choose medications that will improve their patients' quality of life as well as overall health. The side effect profiles of the atypical antipsychotics are more advantageous than those of the conventional neuroleptics. Conventional agents are associated with unwanted central nervous system effects, including extrapyramidal symptoms (EPS), tardive dyskinesia, sedation, and possible impairment of some cognitive measures, as well as cardiac effects, orthostatic hypotension, hepatic changes, anticholinergic side effects, sexual dysfunction, and weight gain. The newer atypical agents have a lower risk of EPS, but are associated in varying degrees with sedation, cardiovascular effects, anticholinergic effects, weight gain, sexual dysfunction, hepatic effects, lowered seizure threshold (primarily clozapine), and agranulocytosis (clozapine only). Since the incidence and severity of specific adverse effects differ among the various atypicals, the clinician should carefully consider which side effects are most likely to lead to the individual's dissatisfaction and noncompliance before choosing an antipsychotic for a particular patient.

Topics: Agranulocytosis; Antipsychotic Agents; Basal Ganglia Diseases; Benzodiazepines; Central Nervous System Diseases; Clozapine; Dibenzothiazepines; Drug Interactions; Dyskinesia, Drug-Induced; Health Status; Humans; Hypotension, Orthostatic; Olanzapine; Pirenzepine; Quality of Life; Quetiapine Fumarate; Receptors, Cholinergic; Risperidone; Schizophrenia; Sexual Dysfunctions, Psychological; Sleep Wake Disorders; Treatment Refusal; Weight Gain

Schizophrenia is associated with impaired sleep continuity. The second generation antipsychotics clozapine and olanzapine have been reported to improve sleep continuity but also to rarely induce restless legs syndrome (RLS). The aims of this randomized double-blind study were to compare the effects of clozapine and olanzapine on sleep and the occurrence of RLS. Therefore, polysomnographies were recorded and RLS symptoms were assessed in 30 patients with schizophrenia before and after 2, 4 and 6 weeks of treatment with either clozapine or olanzapine. Treatment with both antipsychotics increased total sleep time, sleep period time and sleep efficiency and decreased sleep onset latency. These changes were similar in both groups, occurred during the first 2 treatment weeks and were sustained. For example, sleep efficiency increased from 83% (olanzapine) and 82% (clozapine) at baseline to 95% at week 2 and 97% at week 6 in both treatment groups. Sleep architecture was differently affected: clozapine caused a significantly stronger increase of stage 2 sleep (44%) than olanzapine (11%) but olanzapine a significantly stronger increase of REM-sleep. Olanzapine caused an 80% increase of slow wave sleep whereas clozapine caused a 6% decrease. No patient reported any of 4 RLS defining symptoms at baseline. During treatment, 1 patient of each group reported at one visit all 4 symptoms, i.e. met the diagnosis of an RLS. In conclusion, sleep continuity similarly improved and sleep architecture changed more physiologically with olanzapine. Neither of the antipsychotics induced RLS symptoms that were clinically relevant.

Topics: Adolescent; Adult; Aged; Analysis of Variance; Antipsychotic Agents; Benzodiazepines; Clozapine; Databases, Factual; Double-Blind Method; Female; Humans; Male; Middle Aged; Olanzapine; Polysomnography; Schizophrenia; Sleep Wake Disorders; Time Factors; Treatment Outcome; Young Adult

Memory deficits and sleep disturbances are common clinical features of schizophrenia. Sleep is supposed to promote memory consolidation and the antipsychotic olanzapine is suggested to improve both sleep and memory functions. Therefore we performed a study to analyse the acute effects of olanzapine on distinct sleep parameters and sleep-related memory consolidation in parallel.. We studied 26 patients with schizophrenia on stable antipsychotic medication with amisulpride (age range 19-44 years). Immediately before polysomnography and the morning after we performed neuropsychological tasks. Before the third night in the sleep laboratory, patients received either olanzapine or a placebo.. We found a significant positive association for slow wave sleep and declarative memory performance in schizophrenia at baseline. Additionally, Stage 2 sleep spindle density was positively related to overnight memory consolidation. Olanzapine caused a significant increase in the amount of slow wave sleep in accordance with recent studies, but led also to a significant decrease in sleep spindle density, which had not been described before. Memory performance the next morning was not different between the two groups.. Since not only slow wave sleep but also sleep spindles are supposed to promote sleep-related memory consolidation, we suggest that a putative positive effect on memory performance by slow wave sleep augmentation is neutralised by the decrease in sleep spindles due to olanzapine.

Topics: Adult; Antipsychotic Agents; Benzodiazepines; Female; Humans; Male; Memory Disorders; Neuropsychological Tests; Olanzapine; Polysomnography; Psychiatric Status Rating Scales; Schizophrenia; Sleep Stages; Sleep Wake Disorders; Surveys and Questionnaires

This 52-week randomized, double-blind, flexible-dose, multicenter study evaluated the overall effectiveness (as measured by treatment discontinuation rates) of olanzapine, quetiapine, and risperidone in patients early in the course of psychotic illness.. Patients were randomly assigned to treatment with olanzapine (2.5-20 mg/day), quetiapine (100-800 mg/day), or risperidone (0.5-4 mg/day) administered in twice-daily doses. Statistical analyses tested for noninferiority in all-cause treatment discontinuation rates up to 52 weeks (primary outcome measure) based on a prespecified noninferiority margin of 20%.. A total of 400 patients were randomly assigned to treatment with olanzapine (N=133), quetiapine (N=134), or risperidone (N=133). The mean modal prescribed daily doses were 11.7 mg for olanzapine, 506 mg for quetiapine, and 2.4 mg for risperidone. At week 52, all-cause treatment discontinuation rates were 68.4%, 70.9%, and 71.4% for olanzapine, quetiapine, and risperidone, respectively. Reductions in total score on the Positive and Negative Syndrome Scale (PANSS) were similar for the three treatment groups, but reductions in PANSS positive subscale scores were greater in the olanzapine group (at 12 weeks and at 52 weeks or withdrawal from study) and the risperidone group (at 12 weeks). The most common elicited adverse events for olanzapine were drowsiness (53%), weight gain (51%), and insomnia (38%); for quetiapine, drowsiness (58%), increased sleep hours (42%), and weight gain (40%); and for risperidone, drowsiness (50%), menstrual irregularities in women (47%), and weight gain (41%).. Olanzapine, quetiapine, and risperidone demonstrated comparable effectiveness in early-psychosis patients, as indicated by similar rates of all-cause treatment discontinuation.

Topics: Adolescent; Adult; Antipsychotic Agents; Benzodiazepines; Dibenzothiazepines; Double-Blind Method; Drug Administration Schedule; Female; Humans; Male; Olanzapine; Patient Dropouts; Psychiatric Status Rating Scales; Psychotic Disorders; Quetiapine Fumarate; Risperidone; Schizophrenia; Sleep Stages; Sleep Wake Disorders; Treatment Outcome; Weight Gain

Weight gain is commonly observed with olanzapine treatment and can increase the risk for obesity, cardiovascular disease, hypertension, and diabetes mellitus. This study examined the effectiveness of sibutramine, an approved weight loss agent, in overweight and obese subjects taking olanzapine for schizophrenia or schizoaffective disorder.. Each subject had a DSM-IV diagnosis of schizophrenia or schizoaffective disorder, had been taking a stable dose of olanzapine for at least 4 months, and had a body mass index of >/=30 kg/m(2) or >/=27 kg/m(2) plus at least one cardiovascular risk factor. In a 12-week double-blind, randomized, placebo-controlled study, 37 subjects received placebo or sibutramine (up to 15 mg/day). For the first 8 weeks all subjects participated in weekly group sessions focused on nutrition and behavioral modification.. The sibutramine and placebo groups had no significant baseline differences on age, gender, education, ethnicity, diagnosis, weight, body mass index, and blood pressure. At week 12 the sibutramine group had significantly greater losses than the placebo group in weight (mean=8.3 lb, SD=2.4, versus mean=1.8 lb, SD=1.6), waist circumference, body mass index, and hemoglobin A(1c). There were no significant differences on most side effects, although the sibutramine group exhibited a mean increase in systolic blood pressure of 2.1 mm Hg (SD=8.5), and anticholinergic side effects and sleep disturbances were at least twice as common in the sibutramine group.. Sibutramine was an effective and well-tolerated adjunct to behavior modification for weight loss in patients with schizophrenia and schizoaffective disorder being treated with olanzapine.

Topics: Adult; Antipsychotic Agents; Appetite Depressants; Behavior Therapy; Benzodiazepines; Combined Modality Therapy; Cyclobutanes; Double-Blind Method; Female; Humans; Male; Obesity; Olanzapine; Placebos; Psychotic Disorders; Schizophrenia; Sleep Wake Disorders; Treatment Outcome; Weight Gain

Older individuals with dementia are highly sensitive to the effects of muscarinic receptor blockade.. This was a 6-week multisite, randomized clinical trial.. Eighty-six patients with probable Alzheimer's disease, vascular dementia, or mixed-etiology dementia (DSM-IV criteria) were randomly assigned to treatment with olanzapine or risperidone.. Anticholinergic activity was measured with a radioreceptor assay, and plasma levels of antipsychotic medications were determined. Primary outcomes were assessed with the Udvalg for Kliniske Undersogelser (UKU) scale and somnolence adverse events; secondary outcome measures included scores on the Neuropsychiatric Inventory (NPI) and other scales.. There were no between-treatment differences in the UKU scale or in somnolence adverse events. Statistically significant improvements (p < .001) from baseline were found for the NPI measures, with no between-treatment group differences. Olanzapine was associated with significant increases from baseline in anticholinergic activity, while risperidone was not; the between-treatment group differences were not statistically significant. Increase in anticholinergic activity was associated with an increase in anticholinergic side effects and slower performance on the Trail Making Test Part A. Higher endpoint anticholinergic activity was associated with higher endpoint scores on several items from the NPI, including delusions, anxiety, and aberrant motor behavior.. Efficacious doses of olanzapine increased anticholinergic activity in older patients with dementia, while similarly efficacious doses of risperidone did not. Patients whose anticholinergic activity increased were more likely to experience anticholinergic side effects and to have worsening in certain cognitive domains. These data suggest that certain patients may be vulnerable to the anticholinergic activity associated with antipsychotic treatment.

Topics: Antipsychotic Agents; Basal Ganglia Diseases; Benzodiazepines; Cognition Disorders; Delusions; Dementia; Double-Blind Method; Female; Hallucinations; Humans; Male; Middle Aged; Muscarinic Antagonists; Olanzapine; Psychiatric Status Rating Scales; Psychotic Disorders; Radioligand Assay; Receptors, Muscarinic; Risperidone; Sleep Wake Disorders; Trail Making Test; Treatment Outcome

The first double-blind placebo-controlled clinical trial of an atypical neuroleptic medication is being conducted in symptomatic treatment-seeking patients meeting new diagnostic criteria for a putative prodromal syndrome. This identifies them as being at high risk for developing psychosis in the near future. The study aims include prevention of psychosis onset and disability, as well as palliation of ongoing symptomatology. The purpose of this report is to describe the study's "prodromally symptomatic" sample at baseline, i.e., at intake immediately prior to randomization and prior to receiving study medication. Sixty treatment-seeking patients meeting prodromal inclusion criteria were recruited across four sites: New Haven, CT (n=39), Toronto, Ontario (n=9), Calgary, Alberta (n=6), and Chapel Hill, NC (n=6). The sample was young (median age 16), largely male (65%), and came from families with high titers of serious mental illness (44%). Most patients (93%) met criteria for the Attenuated Positive Symptom (APS) prodromal syndrome and presented with significant but nonpsychotic suspiciousness, perceptual aberrations, unusual thought content, and conceptual disorganization. They presented with minimal to mild affective symptoms and substance use/abuse, but they were quite functionally compromised (mean Global Assessment of Functioning (GAF) score=42). The prodromal sample was compared with other clinical-trial samples of adolescent depression, adolescent mania, and first episode schizophrenia. Prodromal patients proved not to be depressed or manic. They were less severely ill than untreated first episode schizophrenia but more severely ill than treated first episode schizophrenia. While not psychotically disabled, these patients nevertheless present with a clinical syndrome. Subsequent reports will detail the effects of drug versus placebo on prodromal symptoms, neuropsychological profile, and the rate of conversion to psychosis.

Topics: Adolescent; Adult; Antipsychotic Agents; Benzodiazepines; Bipolar Disorder; Comorbidity; Depressive Disorder, Major; Double-Blind Method; Female; Humans; Male; Mood Disorders; Olanzapine; Pirenzepine; Psychomotor Disorders; Psychotic Disorders; Risk Factors; Schizophrenia; Schizophrenic Psychology; Sleep Wake Disorders; Speech Disorders

Posttraumatic stress disorder (PTSD), particularly in combat veterans with chronic illness, is often refractory to standard pharmacological interventions. There is a need to test adjunctive treatments to boost response.. Subjects were 19 patients with PTSD who were minimally responsive to 12 weeks of treatment with a selective serotonin reuptake inhibitor (SSRI) at maximum tolerated dose. Outcomes were compared among subjects whose treatment was augmented with 8 weeks of double-blind olanzapine or placebo administration.. Olanzapine augmentation was associated with statistically significantly greater reduction than placebo in specific measures of posttraumatic stress, depressive, and sleep disorder symptoms. Clinician-rated global response rates did not, however, significantly differ between groups.. This is most likely the first double-blind, placebo-controlled study of an adjunct to SSRIs for PTSD. Despite the small group size, the findings suggest a role for olanzapine or other atypical antipsychotics in treating SSRI-resistant PTSD. Sleep symptoms may especially benefit.

Topics: Antipsychotic Agents; Benzodiazepines; Combat Disorders; Depressive Disorder; Double-Blind Method; Drug Administration Schedule; Drug Therapy, Combination; Fluoxetine; Humans; Male; Middle Aged; Olanzapine; Paroxetine; Pirenzepine; Placebos; Psychiatric Status Rating Scales; Selective Serotonin Reuptake Inhibitors; Sertraline; Sleep Wake Disorders; Treatment Outcome

This first clinical study of olanzapine in Japanese patients with schizophrenia was conducted to investigate the efficacy and safety of olanzapine. Eighty-one patients were included in the analysis set. Mean modal dose for those patients were 9.4 +/- 3.6 mg/day. For the primary efficacy measure (Final Global Improvement Rating score), 14.8% of patients had remarkable improvement, 59.3% of patients had moderate improvement or better, and 86.4% of patients had slight improvement or better. Results from the Brief Psychiatric Rating Scale showed improvement from baseline in all clusters including positive psychotic symptoms (thought disturbance) but also against negative symptoms (anergia). The most commonly reported treatment-emergent signs and symptoms with > or =10% incidence, were insomnia, weight increase, excitement, sleepiness, and anxiety. There was a low incidence of extrapyramidal treatment-emergent signs and symptoms, and events reported were tremor (6.2%), muscle rigidity (3.7%), and akathisia (2.5%). The most commonly reported treatment-emergent laboratory changes, with > or = 20% of incidence, were prolactin elevations (24.3%) followed by increases in triglycerides (20.4%). However, mean prolactin values tended to be normalized during the study. This study result suggests that olanzapine is an "atypical" antipsychotic.

Topics: Adult; Akathisia, Drug-Induced; Antipsychotic Agents; Anxiety; Benzodiazepines; Female; Humans; Japan; Male; Muscle Rigidity; Olanzapine; Pirenzepine; Prolactin; Psychiatric Status Rating Scales; Psychomotor Agitation; Schizophrenia; Sleep Wake Disorders; Treatment Outcome; Tremor; Triglycerides; Weight Gain

We compared the efficacy and safety of olanzapine vs placebo for the treatment of acute bipolar mania.. Four-week, randomized, double-blind, parallel study. A total of 115 patients with a DSM-IV diagnosis of bipolar disorder, manic or mixed, were randomized to olanzapine, 5 to 20 mg/d (n = 55), or placebo (n = 60). The primary efficacy measure was the Young-Mania Rating Scale (Y-MRS) total score. Response and euthymia were defined, a priori, as at least a 50% improvement from baseline to end point and as a score of no less than 12 at end point in the Y-MRS total score, respectively. Safety was assessed using adverse events, Extrapyramidal Symptom (EPS) rating scales, laboratory values, electrocardiograms, vital signs, and weight change.. Olanzapine-treated patients demonstrated a statistically significant greater mean (+/- SD) improvement in Y-MRS total score than placebo-treated patients (-14.8 +/- 12.5 and -8.1 +/- 12.7, respectively; P<.001), which was evident at the first postbaseline observation 1 week after randomization and was maintained throughout the study (last observation carried forward). Olanzapine-treated patients demonstrated a higher rate of response (65% vs 43%, respectively; P =.02) and euthymia (61% vs 36%, respectively; P =. 01) than placebo-treated patients. There were no statistically significant differences in EPSs between groups. However, olanzapine-treated patients had a statistically significant greater mean (+/- SD) weight gain than placebo-treated patients (2.1 +/- 2.8 vs 0.45 +/- 2.3 kg, respectively) and also experienced more treatment-emergent somnolence (21 patients [38.2%] vs 5 [8.3% ], respectively).. Olanzapine demonstrated greater efficacy than placebo in the treatment of acute bipolar mania and was generally well tolerated.

Topics: Acute Disease; Adolescent; Adult; Aged; Antipsychotic Agents; Benzodiazepines; Bipolar Disorder; Double-Blind Method; Female; Humans; Male; Middle Aged; Olanzapine; Pirenzepine; Placebos; Psychiatric Status Rating Scales; Severity of Illness Index; Sleep Wake Disorders; Treatment Outcome; Weight Gain

The use of opioids for pain management is often associated with nausea and vomiting. Although conventional antipsychotics are often used to counter emesis, they can be associated with extrapyramidal symptoms. However, chronic pain can induce sleep disturbance. The authors investigated the effects of the atypical antipsychotic olanzapine on morphine-induced emesis and the sleep dysregulation associated with chronic pain.. A receptor binding assay was performed using mouse whole brain tissue. The emetic response in ferrets was evaluated by counting retching and vomiting behaviors. Catalepsy in mice was evaluated by placing both of their forepaws over a horizontal bar. Released dopamine was measured by an in vivo microdialysis study. Sleep disturbance in mice in a neuropathic pain-like state was assayed by electroencephalogram and electromyogram recordings.. Olanzapine showed high affinity for muscarinic M1 receptor in brain tissue. Olanzapine decreased morphine-induced nausea and vomiting in a dose-dependent manner. However, olanzapine at a dose that had an antiemetic effect (0.03 mg/kg) did not induce catalepsy or hyperglycemia. In addition, olanzapine at this dose had no effect on the morphine-induced release of dopamine or inhibition of gastrointestinal transit. Finally, olanzapine inhibited thermal hyperalgesia and completely alleviated the sleep disturbance induced by sciatic nerve ligation.. These findings suggest that olanzapine may be useful for the treatment of morphine-induced emesis and as an adjunct for the treatment of neuropathic pain associated with sleep disturbance.

Topics: Analgesics, Opioid; Animals; Antipsychotic Agents; Benzodiazepines; Blood Glucose; Brain Chemistry; Catalepsy; Clozapine; Dopamine; Drug Therapy, Combination; Electroencephalography; Electromyography; Gastrointestinal Transit; Hyperalgesia; Male; Mice; Mice, Inbred C57BL; Microdialysis; Morphine; Neuralgia; Olanzapine; Pain Management; Receptors, Serotonin; Sciatica; Sleep Wake Disorders; Vomiting

Topics: Antipsychotic Agents; Arm; Benzodiazepines; Humans; Male; Olanzapine; Paresthesia; Schizophrenia; Sleep Wake Disorders; Young Adult

Several case reports and open label trials describe olanzapine in the treatment of anorexia nervosa (AN). We report 5 adolescents with AN who received olanzapine in addition to psychotherapy for their eating disorder. Body mass index (BMI) of each case increased while on olanzapine. At doses of 5 mg per day and above, patients reported decreased anxiety around eating, improved sleep, and decreased rumination about food and body concerns. Morning sedation was the most commonly reported adverse effect. Olanzapine appeared to be useful in addition to psychotherapy for these adolescents. This report augments a limited literature on the treatment of this disorder, and an almost nonexistent literature specific to pharmacotherapy for adolescents with AN.

Topics: Adolescent; Anorexia Nervosa; Benzodiazepines; Body Mass Index; Child; Female; Humans; Male; Olanzapine; Psychotherapy; Selective Serotonin Reuptake Inhibitors; Sleep Wake Disorders; Treatment Outcome

Topics: Antipsychotic Agents; Benzodiazepines; Bipolar Disorder; Drug Therapy, Combination; Feeding and Eating Disorders; Humans; Lithium; Male; Middle Aged; Olanzapine; Pirenzepine; Sleep Wake Disorders; Somnambulism

Topics: Adult; Antipsychotic Agents; Benzodiazepines; Humans; Leg; Male; Olanzapine; Pirenzepine; Restless Legs Syndrome; Schizophrenia; Sleep Wake Disorders