Sleep confers a benefit for retention of statistical language learning in 6.5month old infants.

Infants show robust ability to track transitional probabilities within language and can use this information to extract words from continuous speech. The degree to which infants remember these words across a delay is unknown. Given well-established benefits of sleep on long-term memory retention in adults, we examine whether sleep similarly facilitates memory in 6.5month olds. Infants listened to an artificial language for 7minutes, followed by a period of sleep or wakefulness. After a time-matched delay for sleep and wakefulness dyads, we measured retention using the head-turn-preference procedure. Infants who slept retained memory for the extracted words that was prone to interference during the test. Infants who remained awake showed no retention. Within the nap group, retention correlated with three electrophysiological measures (1) absolute theta across the brain, (2) absolute alpha across the brain, and (3) greater fronto-central slow wave activity (SWA).

Cognitive Behavioral Social Rhythm Group Therapy for Veterans with posttraumatic stress disorder, depression, and sleep disturbance: Results from an open trial.

INTRODUCTION: Cognitive Behavioral Social Rhythm Therapy (CBSRT) is a group psychotherapy tailored for Veterans with Posttraumatic Stress Disorder (PTSD), Major Depressive Disorder (MDD), and sleep disturbances. The aims of this study were to introduce and present initial outcomes of Cognitive Behavioral Social Rhythm Therapy (CBSRT), a 12-week skills group therapy designed to improve sleep and mood by reducing chaotic or isolated lifestyles in Veterans with PTSD. METHODS: Twenty-four male Veterans with at least moderate PTSD and MDD participated in this open trial. Main outcomes were the daily sleep diary for sleep disturbances, the Clinician-Administered PTSD Scale (CAPS) for PTSD, and the Hamilton Depression Rating scale for MDD. RESULTS: Veterans improved on all measures (a) with large within subject effects on PTSD symptoms, MDD symptoms, and sleep quality, and (b) with 46-58% of the sample receiving clinically significant benefits on MDD and PTSD symptoms respectively. The consistency of social rhythms was associated with the average reduction in global CAPS scores over time. Only 13% of participants dropped-out of the group therapy prematurely suggesting that this new group therapy is relatively well-tolerated by Veterans. LIMITATIONS: Future research that employs a control condition is necessary to establish efficacy of CBSRT. CONCLUSIONS: Data from this initial pilot study demonstrate that CBSRT may be an effective group treatment option for Veterans presenting with all three symptom complaints. These data also suggest that daily routine may be an important mechanism to consider in the treatment of PTSD symptoms comorbid with depression.

Has adult sleep duration declined over the last 50+ years?

The common assumption that population sleep duration has declined in the past few decades has not been supported by recent reviews, which have been limited to self-reported data. The aim of this review was to assess whether there has been a reduction in objectively recorded sleep duration over the last 50+ years. The literature was searched for studies published from 1960 to 2013, which assessed objective sleep duration (total sleep time (TST)) in healthy normal-sleeping adults. The search found 168 studies that met inclusion criteria, with 257 data points representing 6052 individuals ages 18-88 y. Data were assessed by comparing the regression lines of age vs. TST in studies conducted between 1960 and 1989 vs. 1990-2013. Weighted regression analyses assessed the association of year of study with age-adjusted TST across all data points. Regression analyses also assessed the association of year of study with TST separately for 10-y age categories (e.g., ages 18-27 y), and separately for polysomnographic and actigraphic data, and for studies involving a fixed sleep schedule and participants' customary sleep schedules. Analyses revealed no significant association of sleep duration with study year. The results are consistent with recent reviews of subjective data, which have challenged the notion of a modern epidemic of insufficient sleep.

The Contribution of Treatment Allocation Method to Outcomes in Intervention Research.

The purpose of this methodological study was to examine the contribution of treatment allocation method (random vs. preference) on the immediate, intermediate, and ultimate outcomes of a behavioural intervention (MCI) for insomnia. Participants were allocated to the MCI randomly or by preference. Outcomes were assessed before, during, and after completion of the MCI using validated self-report measures. Analysis of covariance was used to compare the post-test outcomes for the 2 groups, controlling for baseline differences. Compared to those randomized, participants in the preference group showed improvement in most immediate outcomes (sleep onset latency, wake after sleep onset, sleep efficiency), both intermediate outcomes (insomnia severity and daytime fatigue), and one ultimate outcome (resolution of insomnia). Using a systematic method for eliciting participants' preferences and involving participants in treatment selection had a beneficial impact on immediate and intermediate outcomes. Additional research should validate the mechanism through which treatment preferences contribute to outcomes.

La présente étude méthodologique vise à analyser l'incidence de la méthode d'attribution des traitements (aléatoire ou fondée sur les préférences) sur les résultats immédiats, intermédiaires et ultimes d'une intervention comportementale (MCI) destinée à traiter l'insomnie. Les participants se sont vu attribuer une MCI selon une méthode aléatoire ou fondée sur les préférences. Les résultats ont été analysés avant, pendant et après la fin de la thérapie à l'aide d'un instrument d'autoévaluation validé. Une analyse de la covariance a servi à comparer les résultats au post-test des deux groupes en tenant compte des différences de départ. La comparaison montre une amélioration chez les sujets du groupe avec attribution fondée sur les préférences en ce qui concerne la plupart des résultats immédiats (latence du sommeil, temps d'éveil après l'endormissement, efficacité du sommeil), les deux résultats intermédiaires (gravité de l'insomnie, fatigue diurne) et un résultat ultime (résolution des problèmes d'insomnie). Le fait d'avoir recouru à une méthode systématique pour amener les sujets à exprimer leurs préférences et à les faire participer au choix du traitement a eu un effet bénéfique sur les résultats immédiats et intermédiaires. D'autres recherches devraient permettre de valider le mécanisme par lequel les préférences en matière de traitement contribuent aux résultats.

Attrition in Randomized and Preference Trials of Behavioural Treatments for Insomnia.

Preferences for treatment contribute to attrition. Providing participants with their preferred treatment, as done in a partially randomized clinical or preference trial (PRCT), is a means to mitigate the influence of treatment preferences on attrition. This study examined attrition in an RCT and a PRCT. Persons with insomnia were randomly assigned (n = 150) or allocated (n = 198) to the preferred treatment. The number of dropouts at different time points in the study arms was documented and the influence of participant characteristics and treatment-related factors on attrition was examined. The overall attrition rate was higher in the RCT arm (46%) than in the PRCT arm (33%). In both arms, differences in sociodemographic and clinical characteristics were found between dropouts and completers. The type of treatment significantly predicted attrition (all p ≤ .05). The results provide some evidence of a lower attrition rate in the PRCT arm, supporting the benefit of accounting for preferences as a method of treatment allocation.

Les préférences en matière de traitement influent sur le taux d'abandon. Offrir aux participants le traitement qui correspond à leurs préférences, comme dans le cadre d'un essai clinique avec répartition partiellement aléatoire ou selon les préférences, constitue un moyen d'atténuer l'incidence de la préférence en matière de traitement sur le taux d'abandon. La présente étude examine les taux d'abandon observés lors d'un essai clinique avec répartition aléatoire et d'un essai clinique avec répartition partiellement aléatoire ou selon les préférences. Un groupe de personnes souffrant d'insomnie se sont vu attribuer une thérapie comportementale de façon aléatoire (n = 150) et les membres d'un autre groupe selon leurs préférences (n = 198). Le nombre d'abandons au sein de chacun des groupes a été consigné à différents moments de l'étude, puis une analyse des caractéristiques des participants et des facteurs liés à chaque thérapie a été effectuée afin de déterminer leur influence sur le taux d'abandon. Le taux d'abandon global s'est avéré plus élevé au sein du groupe avec attribution aléatoire de la thérapie (44 %) qu'au sein de l'autre groupe (33 %). Dans les deux groupes, des différences d'ordre sociodémographique et liées à des caractéristiques cliniques ont été observées entre les participants ayant abandonné et ceux qui ont terminé la thérapie. Le type de thérapie suivi permettait de prédire de façon notable s'il y aurait abandon (tout p ≤ 0,05). Les résultats montrent un taux d'abandon moins élevé parmi les participants qui se sont vu attribuer une thérapie selon leurs préférences, ce qui appuie l'hypothèse selon laquelle il y a un avantage à tenir compte des préférences dans la méthode d'attribution des traitements.

Method of Treatment Allocation: Does It Affect Adherence to Behavioural Therapy for Insomnia?

Adherence to treatment is critical in determining the effects of behavioural therapy and may be affected by participants' preference for treatment. The purpose of this study was to determine the extent to which method of allocation to treatment (random vs. preference-based) influences adherence (exposure and enactment) to behavioural therapy. Participants received behavioural therapy for the management of insomnia randomly or by preference. Exposure was assessed as attendance at the treatment sessions, enactment as self-reported application of treatment recommendations. Participants (N = 262) attended a mean of 5.6 treatment sessions, applied the treatment recommendations frequently, and reported high levels of overall compliance. There was no difference between the random and preference groups in terms of exposure to and enactment of treatment. Randomization to the preferred treatment, dissatisfaction with the allocated treatment, and self-report bias could play a role in the findings and should be explored in future research.

L'adhésion au traitement a un effet déterminant sur l'efficacité d'une thérapie comportementale et est susceptible d'être influencée par les préférences des participants en matière de traitement. L'objectif de la présente étude est de déterminer la mesure dans laquelle la méthode d'attribution des traitements (aléatoire ou fondée sur les préférences) exerce une influence sur l'adhésion (exposition ou mise en action) à une thérapie comportementale. Les participants à l'étude se sont vu attribuer une thérapie pour la gestion de l'insomnie selon une méthode aléatoire ou fondée sur leurs préférences. L'exposition a été définie et évaluée comme une présence aux séances de thérapie et la mise en action comme l'application des recommandations associées à la thérapie, selon les déclarations des participants eux-mêmes. Les participants (N = 262) ont assisté en moyenne à 5,6 séances de thérapie, ont appliqué les recommandations associées à la thérapie de façon fréquente et ont indiqué avoir fait preuve d'un degré élevé de respect de la thérapie en général. Aucune différence n'a été observée entre les groupes avec attribution aléatoire et ceux avec attribution selon les préférences en ce qui concerne l'exposition à la thérapie et la mise en action de celle-ci. La répartition aléatoire des participants à la thérapie préférée, l'insatisfaction de participants quant à la thérapie attribuée et le caractère subjectif des déclarations des participants ont possiblement joué un rôle dans l'établissement des résultats et devraient être analysés plus en profondeur dans le cadre d'une prochaine étude.

Performance evaluation of an automated single-channel sleep-wake detection algorithm.

BACKGROUND: A need exists, from both a clinical and a research standpoint, for objective sleep measurement systems that are both easy to use and can accurately assess sleep and wake. This study evaluates the output of an automated sleep-wake detection algorithm (Z-ALG) used in the Zmachine (a portable, single-channel, electroencephalographic [EEG] acquisition and analysis system) against laboratory polysomnography (PSG) using a consensus of expert visual scorers. METHODS: Overnight laboratory PSG studies from 99 subjects (52 females/47 males, 18-60 years, median age 32.7 years), including both normal sleepers and those with a variety of sleep disorders, were assessed. PSG data obtained from the differential mastoids (A1-A2) were assessed by Z-ALG, which determines sleep versus wake every 30 seconds using low-frequency, intermediate-frequency, and high-frequency and time domain EEG features. PSG data were independently scored by two to four certified PSG technologists, using standard Rechtschaffen and Kales guidelines, and these score files were combined on an epoch-by-epoch basis, using a majority voting rule, to generate a single score file per subject to compare against the Z-ALG output. Both epoch-by-epoch and standard sleep indices (eg, total sleep time, sleep efficiency, latency to persistent sleep, and wake after sleep onset) were compared between the Z-ALG output and the technologist consensus score files. RESULTS: Overall, the sensitivity and specificity for detecting sleep using the Z-ALG as compared to the technologist consensus are 95.5% and 92.5%, respectively, across all subjects, and the positive predictive value and the negative predictive value for detecting sleep are 98.0% and 84.2%, respectively. Overall κ agreement is 0.85 (approaching the level of agreement observed among sleep technologists). These results persist when the sleep disorder subgroups are analyzed separately. CONCLUSION: This study demonstrates that the Z-ALG automated sleep-wake detection algorithm, using the single A1-A2 EEG channel, has a level of accuracy that is similar to PSG technologists in the scoring of sleep and wake, thereby making it suitable for a variety of in-home monitoring applications, such as in conjunction with the Zmachine system.

Chronic moderate sleep restriction in older long sleepers and older average duration sleepers: a randomized controlled trial.

Epidemiologic studies have consistently shown that sleeping <7 h and ≥8 h is associated with increased mortality and morbidity. The risks of short sleep may be consistent with results from experimental sleep deprivation studies. However, there has been little study of chronic moderate sleep restriction and little evaluation of older adults who might be more vulnerable to negative effects of sleep restriction, given their age-related morbidities. Moreover, the risks of long sleep have scarcely been examined experimentally. Moderate sleep restriction might benefit older long sleepers who often spend excessive time in bed (TIB) in contrast to older adults with average sleep patterns. Our aims are: (1) to examine the ability of older long sleepers and older average sleepers to adhere to 60 min TIB restriction; and (2) to contrast effects of chronic TIB restriction in older long vs. average sleepers. Older adults (n = 100) (60-80 years) who sleep 8-9 h per night and 100 older adults who sleep 6-7.25 h per night will be examined at 4 sites over 5 years. Following a 2-week baseline, participants will be randomized to one of two 12-week treatments: (1) a sleep restriction involving a fixed sleep-wake schedule, in which TIB is reduced 60 min below each participant's baseline TIB; and (2) a control treatment involving no sleep restriction, but a fixed sleep schedule. Sleep will be assessed with actigraphy and a diary. Measures will include glucose tolerance, sleepiness, depressive symptoms, quality of life, cognitive performance, incidence of illness or accident, and inflammation.

Mindfulness-based cognitive therapy improves polysomnographic and subjective sleep profiles in antidepressant users with sleep complaints.

BACKGROUND: Many antidepressant medications (ADM) are associated with disruptions in sleep continuity that can compromise medication adherence and impede successful treatment. The present study investigated whether mindfulness meditation (MM) training could improve self-reported and objectively measured polysomnographic (PSG) sleep profiles in depressed individuals who had achieved at least partial remission with ADM, but still had residual sleep complaints. METHODS: Twenty-three ADM users with sleep complaints were randomized into an 8-week Mindfulness-Based Cognitive Therapy (MBCT) course or a waitlist control condition. Pre-post measurements included PSG sleep studies and subjectively reported sleep, residual depression symptoms. RESULTS: Compared to controls, the MBCT participants improved on both PSG and subjective measures of sleep. They showed a pattern of decreased wake time and increased sleep efficiency. Sleep depth, as measured by stage 1 and slow-wave sleep, did not change as a result of mindfulness training. CONCLUSIONS: MM is associated with increases in both objectively and subjectively measured sleep continuity in ADM users. MM training may serve as more desirable and cost-effective alternative to discontinuation or supplementation with hypnotics, and may contribute to a more sustainable recovery from depression.

Nonlinear dynamical systems effects of homeopathic remedies on multiscale entropy and correlation dimension of slow wave sleep EEG in young adults with histories of coffee-induced insomnia.

BACKGROUND: Investigators of homeopathy have proposed that nonlinear dynamical systems (NDS) and complex systems science offer conceptual and analytic tools for evaluating homeopathic remedy effects. Previous animal studies demonstrate that homeopathic medicines alter delta electroencephalographic (EEG) slow wave sleep. The present study extended findings of remedy-related sleep stage alterations in human subjects by testing the feasibility of using two different NDS analytic approaches to assess remedy effects on human slow wave sleep EEG. METHODS: Subjects (N=54) were young adult male and female college students with a history of coffee-related insomnia who participated in a larger 4-week study of the polysomnographic effects of homeopathic medicines on home-based all-night sleep recordings. Subjects took one bedtime dose of a homeopathic remedy (Coffea cruda or Nux vomica 30c). We computed multiscale entropy (MSE) and the correlation dimension (Mekler-D2) for stages 3 and 4 slow wave sleep EEG sampled in artifact-free 2-min segments during the first two rapid-eye-movement (REM) cycles for remedy and post-remedy nights, controlling for placebo and post-placebo night effects. RESULTS: MSE results indicate significant, remedy-specific directional effects, especially later in the night (REM cycle 2) (CC: remedy night increases and post-remedy night decreases in MSE at multiple sites for both stages 3 and 4 in both REM cycles; NV: remedy night decreases and post-remedy night increases, mainly in stage 3 REM cycle 2 MSE). D2 analyses yielded more sporadic and inconsistent findings. CONCLUSIONS: Homeopathic medicines Coffea cruda and Nux vomica in 30c potencies alter short-term nonlinear dynamic parameters of slow wave sleep EEG in healthy young adults. MSE may provide a more sensitive NDS analytic method than D2 for evaluating homeopathic remedy effects on human sleep EEG patterns.

Dismantling multicomponent behavioral treatment for insomnia in older adults: a randomized controlled trial.

STUDY OBJECTIVE: Recently, the use of multicomponent insomnia treatment has increased. This study compares the effect of single component and multicomponent behavioral treatments for insomnia in older adults after intervention and at 3 months and 1 yr posttreatment. DESIGN: A randomized, controlled study. SETTING: Veterans Affairs medical center. PARTICIPANTS: 179 older adults (mean age, 68.9 yr ± 8.0; 115 women [64.2%]) with chronic primary insomnia. INTERVENTIONS: Participants were randomly assigned to 6 wk of stimulus control therapy (SCT), sleep restriction therapy (SRT), the 2 therapies combined into a multicomponent intervention (MCI), or a wait-list control group. MEASUREMENTS AND RESULTS: Primary outcomes were subjective (daily sleep diary) and objective (actigraphy) measures of sleep-onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), time in bed (TIB), and sleep efficiency (SE). Secondary outcomes were clinical measures including response and remission rates. There were no differences between the single and multicomponent interventions on primary sleep outcomes measured by diary and actigraphy. All treatments produced significant improvement in diary-reported sleep in comparison with the control group. Effect sizes for sleep diary outcomes were medium to large. Treatment gains were maintained at follow-up for diary and actigraph measured SOL, WASO, and SE. The MCI group had the largest proportion of treatment remitters. CONCLUSIONS: For older adults with chronic primary insomnia, the findings provide initial evidence that SCT, SRT, and MCI are equally efficacious and produce sustainable treatment gains on diary, actigraphy, and clinical outcomes. From a clinical perspective, MCI may be a preferred treatment due to its higher remission rate. CLINICAL TRIAL INFORMATION: Behavioral Intervention for Insomnia in Older Adults. NCT01154023. URL: http://clinicaltrials.gov/ct2/show/NCT01154023?term=Behavioral+Intervention+for+Insomnia+in+Older+Adults&rank=1.

K-complexes are not preferentially evoked to combat sounds in combat-exposed Vietnam veterans with and without post-traumatic stress disorder.

The primary objective was to compare the evoked K-complex response to salient versus non-salient auditory stimuli in combat-exposed Vietnam veterans with and without post-traumatic stress disorder (PTSD). Three categories of auditory stimuli (standard 1000Hz tones, trauma-related combat sounds, and affectively neutral environmental sounds) were presented during stage 2 sleep utilizing an oddball paradigm with probabilities of occurrence of 60%, 20% and 20% respectively. Twenty-four combat-exposed Vietnam veterans, 14 with PTSD and 10 without PTSD were studied in a sleep laboratory at the National Center for PTSD in Menlo Park, CA. While significantly fewer K-complexes overall were elicited in patients, there were no differences in the proportion of K-complexes elicited by tones and combat stimuli within either group. Patients produced significantly more K-complexes to neutral stimuli than to tone or combat stimuli. Examination of the N550 component of the evoked K-complex revealed significantly longer latencies in the patient group. Across the entire sample, N550 latencies were longer for combat stimuli relative to tone neutral stimuli. There were no group or stimulus category differences for N550 amplitude. The results suggest that salient information, as defined by trauma-related combat sounds, did not preferentially elicit K-complexes in either the PTSD group or the control group, suggesting that K-complexes function to protect sleep more than to endogenously process meaningful stimuli.

Circadian rhythms, sleep, and substance abuse.

Substance abuse is linked to numerous mental and physical health problems, including disturbed sleep. The association between substance use and sleep appears to be bidirectional, in that substance use may directly cause sleep disturbances, and difficulty sleeping may be a risk factor for relapse to substance use. Growing evidence similarly links substance use to disturbances in circadian rhythms, although many gaps in knowledge persist, particularly regarding whether circadian disturbance leads to substance abuse or dependence. Given the integral role circadian rhythms play in regulating sleep, circadian mechanisms may account in part for sleep-substance abuse interactions. Furthermore, a burgeoning research base supports a role for the circadian system in regulating reward processing, indicating that circadian mechanisms may be directly linked to substance abuse independently of sleep pathways. More work in this area is needed, particularly in elucidating how sleep and circadian disturbance may contribute to initiation of, and/or relapse to, substance use. Sleep and circadian-based interventions could play a critical role in the prevention and treatment of substance use disorders.

Examination of insomnia and insomnia treatment in psychiatric inpatients.

Despite the high comorbidity of insomnia with psychiatric illness, few studies have examined insomnia or insomnia treatments in psychiatric inpatients. The present study had two overall goals. First, we sought to describe insomnia symptoms in 76 US veterans hospitalized for a wide-range of psychiatric illnesses. Next, we sought to examine whether participation in one session of group therapy for insomnia was associated with improvement in Insomnia Severity Index (ISI) scores for a subset of these inpatients (n = 19). Data were extracted from the clinical charts of 140 inpatients admitted into the 26-bed psychiatric ward at the New Mexico VA Healthcare System. The majority of the veterans had clinical insomnia in the moderate-to-severe range, and only 18% of the sample reported no clinically-significant insomnia. There was a significant reduction in ISI scores approximately 1 week after attendance at the group therapy session, which appears to be unrelated to the length of hospitalization, but might be related to psychiatric stabilization. This is the first study to examine insomnia symptoms in a mixed, psychiatric inpatient population. Group therapy for insomnia might be a particularly useful treatment option given polypharmacy and substance dependency issues often arising in this population.

Understanding and treating insomnia.

Sleep disturbance is intricately entwined with our sense of well-being, health, emotion regulation, performance and productivity, memory and cognitive functioning, and social interaction. A longitudinal perspective underscores the conclusion that persistent sleep disturbance, insomnia, at any time during the life span from infancy to old age has a lasting impact. We examine how insomnia develops, the evidence for competing explanations for understanding insomnia, and the evidence about psychological and behavioral treatments that are used to reduce insomnia and change daytime consequences. There are new directions to expand access to treatment for those who have insomnia, and thus a critical analysis of pathways for dissemination is becoming increasingly important.

Effects of homeopathic medicines on polysomnographic sleep of young adults with histories of coffee-related insomnia.

BACKGROUND: Homeopathy, a common form of alternative medicine worldwide, relies on subjective patient reports for diagnosis and treatment. Polysomnography offers a modern methodology for evaluating the objective effects of taking homeopathic remedies that clinicians claim exert effects on sleep quality in susceptible individuals. Animal studies have previously shown changes in non rapid eye movement sleep with certain homeopathic remedies. METHODS: Young adults of both sexes (ages 18-31) with above-average scores on standardized personality scales for either cynical hostility or anxiety sensitivity (but not both) and a history of coffee-induced insomnia participated in the month-long study. At-home polysomnographic recordings were obtained on successive pairs of nights once per week for a total of eight recordings (nights 1, 2, 8, 9, 15, 16, 22, 23). Subjects (N=54) received placebo pellets on night 8 (single-blind) and verum pellets on night 22 (double-blind) in 30c doses of one of two homeopathic remedies, Nux Vomica or Coffea Cruda. Subjects completed daily morning sleep diaries and weekly Pittsburgh sleep quality index scales, as well as profile of mood states scales at bedtime on polysomnography nights. RESULTS: Verum remedies significantly increased PSG total sleep time and NREM, as well as awakenings and stage changes. Changes in actigraphic and self-rated scale effects were not significant. CONCLUSIONS: The study demonstrated the feasibility of using in-home, all-night sleep recordings to study homeopathic remedy effects. Findings are similar though not identical to those reported in animals with the same remedies. Possible mechanisms include initial disruption of the nonlinear dynamics of sleep patterns by the verum remedies.

Insomnia treatments: moving from efficacy to effectiveness.

This issue of the Journal of Clinical Psychology: In Session focuses on the treatment of insomnia and sleep disturbances in a variety of populations. Over the past decade, there has been an increased recognition of the importance of sleep to health and well-being. Despite this recognition, there continues to be a shortage of practitioners with experience in insomnia therapies. In this article, the authors identify and refute commonly held myths that might hinder the treatment of sleep problems. They conclude by introducing the seven articles that constitute this special issue.

Polysomnographic and subjective profiles of sleep continuity before and after mindfulness-based cognitive therapy in partially remitted depression.

OBJECTIVES: To examine whether mindfulness meditation (MM) was associated with changes in objectively measured polysomnographic (PSG) sleep profiles and to relate changes in PSG sleep to subjectively reported changes in sleep and depression within the context of a randomized controlled trial. Previous studies have indicated that mindfulness and other forms of meditation training are associated with improvements in sleep quality. However, none of these studies used objective PSG sleep recordings within longitudinal randomized controlled trials of naïve subjects. METHODS: Twenty-six individuals with partially remitted depression were randomized into an 8-week Mindfulness-Based Cognitive Therapy (MBCT) course or a waitlist control condition. Pre-post measurements included PSG sleep studies and subjectively reported sleep and depression symptoms. RESULTS: According to PSG sleep, MM practice was associated with several indices of increased cortical arousal, including more awakenings and stage 1 sleep and less slow-wave sleep relative to controls, in proportion to amount of MM practice. According to sleep diaries, subjectively reported sleep improved post MBCT but not above and beyond controls. Beck Depression Inventory scores decreased more in the MBCT group than controls. Improvements in depression were associated with increased subjective sleep continuity and increased PSG arousal. CONCLUSIONS: MM is associated with increases in objectively measured arousal during sleep with simultaneous improvements in subjectively reported sleep quality and mood disturbance. This pattern is similar to the profiles of positive responders to common antidepressant medications.