Adam Wichniak

Heritability of Sleep Electroencephalogram

BACKGROUND Understanding the basis of sleep-related endophenotypes might help to pinpoint factors modulating susceptibility to psychiatric disorders. However, the genetic underpinnings of sleep microarchitecture in humans remain largely unknown. Here we report on the results of a classical twin study in monozygotic (MZ) and dizygotic (DZ) twin pairs examining the genetic effect on sleep electroencephalogram (EEG) composition. METHODS Polysomnographic recordings were obtained in 35 pairs of MZ (26.4 +/- 5.4 years, 17-43 years, 17 male pairs, 18 female pairs) and 14 same-gender pairs of DZ twins (22.1 +/- 2.7 years, 18-26 years, 7 male pairs, 7 female pairs). The EEG power spectra were generated on the basis of Fast Fourier transformations combined with conventional sleep parameters, according to standardized criteria. RESULTS We tested the genetic variance contributing to the observed overall variance of the sleep measures and found that the relative contributions of the delta, theta, alpha, and sigma frequency bands at central derivations were significantly correlated to the genetic background. In these frequency bands, MZ twins also showed within-pair concordance in spectral power that was significantly higher than that of DZ twins. CONCLUSIONS The broad overlap of EEG frequencies during non-REM sleep and wakefulness, which shows a significant genetic variance, supports the hypothesis of common neuronal mechanisms generating EEG oscillations in humans. Our findings strongly support the suitability of the spectral composition of non-REM sleep for defining endophenotypes.

Changes of sleep architecture, spectral composition of sleep EEG, the nocturnal secretion of cortisol, ACTH, GH, prolactin, melatonin, ghrelin, and leptin, and the DEX-CRH test in depressed patients during treatment with mirtazapine.

The noradrenergic and specific serotoninergic antidepressant mirtazapine improves sleep, modulates hormone secretion including blunting of hypothalamic–pituitary–adrenocortical (HPA) activity, and may prompt increased appetite and weight gain. The simultaneous investigation of sleep electroencephalogram (EEG) and hormone secretion during antidepressive treatment helps to further elucidate these effects. We examined sleep EEG (for later conventional and quantitative analyses) and the nocturnal concentrations of cortisol, adrenocorticotropin (ACTH), growth hormone (GH), prolactin, melatonin and the key factors of energy balance, ghrelin, and leptin before and after 28 days of treatment of depressed patients (seven women, three men, mean age 39.9±4.2 years) with mirtazapine. In addition, a sleep EEG was recorded at day 2 and the dexamethasone–corticotropin-releasing hormone (DEX-CRH) test was performed to assess HPA activity at days −3 and 26. Psychometry and mirtazapine plasma concentrations were measured weekly. Already at day 2, sleep continuity was improved. This effect persisted at day 28, when slow-wave sleep, low-delta, theta and alpha activity, leptin and (0300–0700) melatonin increased, and cortisol and ghrelin decreased. ACTH and prolactin remained unchanged. The first two specimens of GH collected after the start of quantitative EEG analysis were reduced at day 28. The DEX-CRH test showed, at day 26, a blunting of the overshoot of ACTH and cortisol found at day −3. The Hamilton Depression score decreased from 32.1±7.3 to 15.5±6.7 between days −1 and 28. A weight gain of approximately 3 kg was observed. This unique profile of changes is compatible with the action of mirtazapine at 5-HT-2 receptors, at presynaptic adrenergic alpha 2 receptors, at the HPA system, and on ghrelin and leptin.

Rhythmic feet movements while falling asleep.

During the wake–sleep transition and sleep, diverse motor phenomena such as hypnagogic foot tremor may occur in the lower extremities. We investigated the relevance of this phenomenon in 375 consecutive subjects examined polysomnographically in a sleep disorders center. Rhythmic feet movements while falling asleep (RFM) were found in 28 subjects (7.5%). RFM occurred mostly as single, short series with a duration of between 10 and 15 seconds. They had a high night‐to‐night variability and were detected as rhythmic, oscillating movements of the whole foot or toes. Surface electromyographic (EMG) recordings displayed series of repetitive phasic bursts with a periodicity mostly between 1 and 2 per second. Single EMG burst duration varied between 300 and 700 msec. RFM at highest intensity occurred during presleep wakefulness, and usually persisted in sleep stages 1 and 2. RFM did not have a major sleep‐disturbing effect in any of the affected subjects. Due to its high prevalence and the lack of a major sleep‐disturbing effect, short series of RFM could be considered a quasiphysiological phenomenon. However, in more severe forms of RFM with evidence of a sleep‐disturbing effect, RFM should be considered abnormal.

Sleep and antidepressant treatment.

The aim of this review was to describe the sleep anomalies in depression, the effects of antidepressants on sleep, the usefulness of antidepressants in the treatment of primary insomnia and insomnia in other psychiatric disorders. Depression is associated with abnormalities in the sleep pattern that include disturbances of sleep continuity, diminished slow-wave sleep (SWS) and altered rapid eye movement (REM) sleep parameters. Although none of the reported changes in sleep are specific to depression, many of them, for example increased REM density and reduced amount of SWS in the first sleep cycle, are used as biological markers for research on depression and in the development of antidepressant drugs. An antidepressant should reverse abnormalities in the sleep pattern. However, many antidepressants can worsen sleep. Because of the activating effects of some drugs, for example imipramine, desipramine, fluoxetine, paroxetine, venlafaxine, reboxetine and bupropion, many patients who take them have to be co-prescribed with sleep-promoting agents to improve sleep. Even in maintenance treatment with activating antidepressants as many as 30-40% of patients may still suffer from insomnia. Antidepressants with sleep-promoting effects include sedative antidepressants, for example doxepin, mirtazapine, trazodone, trimipramine, and agomelatine which promotes sleep not through a sedative action but through resynchronization of the circadian rhythm. Sedative antidepressants are frequently used in the treatment of primary insomnia, although not many double-blind studies have been provided to support such an approach to insomnia treatment. One exception is doxepin, which has been approved for the treatment of insomnia characterized by difficulties in maintaining sleep.

Sleep as a biomarker for depression

Abstract Sleep is a complex biological process that involves cyclic changes of brain activity. The smooth transition between wakefulness and sleep and cyclic succession of sleep stages depend on the function of numerous neurotransmitters that reciprocally influence each other. For this reason sleep is a very sensitive biomarker of brain functioning. This article provides an overview of sleep changes in depression, mechanisms involved in sleep regulation and pathophysiology underlying depression, studies on sleep as a biomarker for depression, effects of antidepressants on sleep EEG, and studies in depression with the use of quantitative sleep EEG analysis. Research on sleep in depression has provided several valuable biomarkers that are related to increased risk for depression, show worsening during depressive episode, and are related to treatment outcome and relapse risk during remission phase. Among many sleep parameters, increased REM density and diminished delta sleep ratio deserve special interest. Sleep studies are also an important research tool for antidepressant drug development. However, due to sensitivity of sleep parameters to pharmacological interventions, the patients have to be investigated before the start of pharmacological treatment or after washout from the antidepressant drug, to obtain reliable data on disease-related biological processes from polysomnography.

Consensus paper of the WFSBP Task Force on Biological Markers: Criteria for biomarkers and endophenotypes of schizophrenia part I: Neurophysiology

Abstract The neurophysiological components that have been proposed as biomarkers or as endophenotypes for schizophrenia can be measured through electroencephalography (EEG) and magnetoencephalography (MEG), transcranial magnetic stimulation (TMS), polysomnography (PSG), registration of event-related potentials (ERPs), assessment of smooth pursuit eye movements (SPEM) and antisaccade paradigms. Most of them demonstrate deficits in schizophrenia, show at least moderate stability over time and do not depend on clinical status, which means that they fulfil the criteria as valid endophenotypes for genetic studies. Deficits in cortical inhibition and plasticity measured using non-invasive brain stimulation techniques seem promising markers of outcome and prognosis. However the utility of these markers as biomarkers for predicting conversion to psychosis, response to treatments, or for tracking disease progression needs to be further studied.

Electroencephalogram slowing, sleepiness and treatment response in patients with schizophrenia during olanzapine treatment

Electroencephalogram (EEG) slowing is associated with clozapine side effects, e.g., sedation, and may predict treatment response during clozapine treatment. As olanzapine and clozapine share many pharmacological properties, we investigated whether EEG slowing during olanzapine treatment was related to therapy outcome and sleepiness in patients with schizophrenia. Participants were age- and gender-matched schizophrenic patients treated with olanzapine (n 54), receiving no pharmacological treatment (n 54), or cotreated with olanzapine and some other psychotropic drug (n 38). Their EEG recordings were assessed visually by the same rater blind to clinical data. The EEG scores were categorized using standardized forms. Patients with a poor treatment response did not differ significantly from those with a good response to treatment either in EEG patterns or in frequency of sleepiness. Olanzapine treatment was associated with increased rates of slow (70.4% vs. 22.3%) and sharp waves (22.2% vs. 7.4%), as well as of paroxysmal slow wave discharges (14.8% vs. 1.9%), but did not induce spike- or sharp-slow-wave complexes. Cotreatment with another antipsychotic further increased EEG abnormalities, whereas benzodiazepine administration diminished the olanzapine-induced EEG changes. The results show that olanzapine inducing both slow and sharp waves, as well as paroxysmal discharges, has a strong impact on EEG. However, as no spike- or sharp-slow-wave complexes were observed, the risk of epileptic seizure during olanzapine treatment can be regarded as low, as long as olanzapine is not combined with some other antipsychotic.

Effects of Antidepressants on Sleep

Purpose of ReviewThe aim of this review article was to summarize recent publications on effects of antidepressants on sleep and to show that these effects not only depend on the kind of antidepressant drugs but are also related to the dose, the time of drug administration, and the duration of the treatment.Recent FindingsComplaints of disrupted sleep are very common in patients suffering from depression, and they are listed among diagnostic criteria for this disorder. Moreover, midnocturnal insomnia is the most frequent residual symptom of depression. Thus, all antidepressants should normalize sleep. However, at least in short-term treatment, many antidepressants with so-called activating effects (e.g. fluoxetine, venlafaxine) may disrupt sleep, while others with sedative properties (e.g., doxepin, mirtazapine, trazodone) rapidly improve sleep, but may cause problems in long-term treatment due to oversedation.For sleep-promoting action, the best effects can frequently be achieved with a very low dose, administered early enough before bedtime and importantly, always as a part of more complex interventions based on the cognitive-behavioral protocol to treat insomnia (CBT-I).SummaryFor successful treatment of depression, it is necessary to understand the effects of antidepressants on sleep. Each physician should also be aware that some antidepressants may worsen or induce primary sleep disorders like restless legs syndrome, sleep bruxism, REM sleep behavior disorder, nightmares, and sleep apnea, which may result from an antidepressant-induced weight gain.

Age or age at onset? Which of them really matters for neuro and social cognition in schizophrenia?

In schizophrenia patients, both an older age and earlier age at onset of the disease are related to worse cognitive functioning. As patients with later schizophrenia onset are also older, analysing the two effects separately can be misleading, as they can either be spurious or cancel one another out. The purpose of the present study was to elucidate the effects of age and onset-age on cognition in schizophrenia patients. Individuals with schizophrenia (N=151), aged 18-59 years, were examined with a MATRICS Consensus Cognitive Battery (MCCB) to get a full picture of their cognitive performance. Results showed age and age at onset indeed interrelated. Regression analyses revealed later onset of schizophrenia related to better social cognition. Patients׳ older age was related to a slower performance in symbol coding task, less effective executive functions, worse visual learning, lower attention, and lower total score in the MCCB. In the above regression analyses we controlled doses of antipsychotic medications. The results suggest that a previously found relationship between older age and social cognition might be spurious, and strengthen observations that it is specifically later onset-age which fosters better social cognition in schizophrenia patients.

Patients with insomnia and subthreshold depression show marked worsening of insomnia after discontinuation of sleep promoting medication.

OBJECTIVE To investigate whether the outcome of treatment with trazodone CR in primary insomnia differs between patients with and without subthreshold depression. METHODS 14 patients (9 females, mean age 57.3 ± 13.3) with primary insomnia and increased Beck Depression Inventory (BDI) scores (>10) and 15 sex- and age-matched patients with primary insomnia and low BDI scores (≤ 10) were treated with trazodone CR 25-150 mg/d for 3 months and followed for 1 month after discontinuation of the medication. The Athens Insomnia Scale (AIS), Sheehan Disability Scale (SDS), and Clinical Global Impression scale (CGI) were completed at baseline, after each month of treatment and after the first week of run-out phase. Additional assessment tools comprised sleep diaries, the Leeds Sleep Evaluation Questionnaire (LSEQ) and actigraphic recordings. RESULTS Subjective sleep time increased by 61.5 ± 72.3 min in the group with low BDI and 60.0 ± 59.4 min in the group with increased BDI at the end of the treatment phase. The significant improvements were also observed in the AIS, CGI, LSEQ and SDS. During the run-out phase the improvement was sustained in patients with low BDI, while AIS scores, sleep latency and total sleep time deteriorated in patients with increased BDI. CONCLUSIONS Patients with subthreshold depression, even if the depressive symptoms do not fulfill the time criteria for depressive episode, show marked worsening of insomnia after discontinuation of sleep promoting medication.