Category: Insomnia

The potentially lasting implications of day-to-day couple conflict on physical and mental well-being are revealed in a study published in the journal Personal Relationships.

Until now research has concentrated on the immediate effects of romantic conflict, typically in controlled laboratory settings. In one of the first studies to look at the longer term, Professor Angela Hicks investigated the physiological and emotional changes taking place in couples the day after conflict occurred, specifically taking into account the differing styles of emotional attachment between participating partners.

"We are interested in understanding links between romantic relationships and long term emotional and physical well-being," said Professor Hicks. "Our findings provide a powerful demonstration of how daily interpersonal dealings affect mood and physiology across time."

Hicks' study involved a sample of 39 participants in established co-habiting relationships, who were tested for the association between conflict (assessed with end-of-day diaries) and sleep disturbance, next-morning reports of negative affect on mood, and cortisol awakening response. Prior to testing, the emotional attachment styles of all participants were measured according to how anxious they were in their relationship, and to what degree they avoided emotional attachment.

The study found that all participants across the sample as a whole experienced sleep disruption after conflict, bearing out the adage "don't go to bed angry." There was however the greatest degree of sleep disruption amongst individuals who were highly anxious in their relationship. The lowest degree of sleep disruption was found amongst individuals who strongly avoided emotional attachment.

Conflict was also found to have repercussions for next-day mood. However, some participants found their mood negatively affected more than others. Individuals more at ease with emotional attachment found their mood was affected more than did individuals less comfortable being intimate with others.

The researchers found no general association between conflict and the next morning cortisol awakening response (a physiological, stress-related preparation for the day ahead). Their findings showed a particular association only, amongst women who were highly anxious in their relationships, whose cortisol response was significantly dampened on days after conflict.

The results of this study have significant implications for the greater understanding of how routine relationship experiences influence emotional and physical health over time. "We already know from prior research that people in stable, happy marriages experience better overall health than do those in more conflicted relationships," said Professor Hicks. "We can now further conclude from our current research that individuals who are in insecure relationships are more vulnerable to longer-term health risks from conflict than are others."

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Journal Reference:

1. Angela M. Hicks, Lisa M. Diamond. Don't go to bed angry: Attachment, conflict, and affective and physiological reactivity. Personal Relationships, 2011; 18 (2): 266 DOI: 10.1111/j.1475-6811.2011.01355.x

— Researchers at the University of Toronto are the first to identify a potential cause for a severe sleep disorder that has been closely linked to Parkinson's disease and other neurodegenerative diseases.

"Our research is the first to establish a potential genetic link to human REM sleep behaviour disorder (RBD). That's important because between 60 and 80 per cent of people diagnosed with human RBD develop Parkinson's disease or other neurodegenerative disorders later in life," says Dr. John Peever, lead author of the study that recently appeared in The Journal of Neuroscience.

Rapid-eye-movement sleep behaviour disorder (RBD) is most often characterized by violent movements that occur during dreaming sleep, also called rapid-eye-movement sleep. People who suffer from RBD do not experience normal muscle paralysis that prevents them from enacting their dreams and they often hurt themselves or their bed partners with their rapid, forceful movements. In some cases, patients need to be tied to their bed to prevent serious injury to themselves or their bedpartners.

Peever's team focused on investigating a genetic cause of RBD because the underlying cause of this disorder is unknown. There is evidence indicating that reduced brain inhibition could cause RBD, so Peever's team genetically reduced brain inhibition in mice and then recorded their sleep and muscle activity.

"We found that mice with reduced brain inhibition acted just like human RBD patients and they moved violently during REM sleep," says Peever. "This link strongly suggests that patients with RBD may also have impaired brain inhibition."

They also found that RBD symptoms in mice could be alleviated by giving them clonazepam — a drug used to treat human RBD.

Peever's research underscores the importance of identifying a cause of RBD as 60 — 80 per cent of RBD sufferers subsequently develop Parkinson's.

"Treating RBD could have direct implications for understanding and perhaps treating Parkinson's disease," says Peever.

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Journal Reference:

1. P. L. Brooks, J. H. Peever. Impaired GABA and Glycine Transmission Triggers Cardinal Features of Rapid Eye Movement Sleep Behavior Disorder in Mice. Journal of Neuroscience, 2011; 31 (19): 7111 DOI: 10.1523/JNEUROSCI.0347-11.2011

Sleeping less at night may increase the expression of genetic risks for obesity, while getting plenty of sleep may suppress genetic influences on body weight, suggests an abstract being presented in Minneapolis, Minn., at SLEEP 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

Results of a study of 1,811 pairs of twins show that the heritability of sleep duration was 32 percent, and shared environmental influences on sleep duration were negligible. Longer sleep duration was associated with decreased body mass index, which is a measure of body fat based on height and weight.

Behavioral genetic modeling found significant interactions between self-reported, habitual sleep duration and both genetic and shared environmental influences on BMI. The heritability of BMI when sleep duration equaled seven hours was more than twice as large as the heritability of BMI when sleep duration equaled nine hours.

"The heritability of body weight decreased as sleep duration increased," said principal investigator Dr. Nathaniel Watson, associate professor of neurology at the University of Washington and co-director of the UW Medicine Sleep Center. "There appears to be something about short sleep that creates a permissive environment for expression of obesity-related genes."

The study involved a population-based sample of 1,811 pairs of identical and fraternal twins from the University of Washington Twin Registry. They had a mean age of about 37 years. Height, weight and habitual sleep duration were collected by self-report surveys. Participants were slightly overweight with a mean BMI of 25.4, and they had a mean sleep duration of about seven hours and 11 minutes per night. Data were analyzed using behavioral genetic interaction models.

According to Watson, the study is an important addition to the existing body of research on the relationship between sleep duration and BMI.

"Epidemiological and experimental studies have shown short sleep is associated with obesity," said Watson. "Our work takes this a step further, showing that short sleep facilitates expression of obesity-related genes."

The authors concluded that future research aiming to identify specific genotypes for BMI may benefit from considering the moderating role of sleep duration.

In a smaller study of 612 twin pairs published in the Journal of Clinical Sleep Medicine in 2010, Watson found that short sleep was associated with elevated BMI following careful adjustment for genetics and shared environment. In a study published in JAMA in 2010, the CDC estimated that 68 percent of U.S. adults were overweight or obese in 2007 — 2008.

Performance deteriorates when sleep is restricted to six hours per night for a week and does not improve after two nights of recovery sleep. However, women may be less affected than men by this workweek pattern of sleep loss, suggests a research abstract being presented in Minneapolis, Minn., at SLEEP 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

Results show that, in both men and women, performance decreased significantly after six nights of sleep restriction and did not improve after two nights of recovery sleep, suggesting that complete performance recovery may require more than just two nights of extended sleep. Sleep restriction also caused subjective and objective sleepiness to increase significantly; however, sleepiness did improve after recovery.

"After one workweek of mild sleep deprivation, two recovery nights were adequate in improving sleepiness but not performance," said principal investigator Dr. Alexandros N. Vgontzas, professor of psychiatry and endowed chair in sleep disorders medicine at the Penn State College of Medicine and director of the Sleep Research and Treatment Center at the Penn State Milton S. Hershey Medical Center in Hershey, Pa. "The usual practice of extending sleep during the weekend after a busy workweek associated with mild sleep loss is not adequate in reversing the cumulative effects on cognitive function resulting from this mild sleep deprivation."

The study also found significant gender differences. Compared with men, women were found to have less subjective sleepiness and less performance deterioration during sleep restriction, as well as greater improvements after recovery. These differences were associated with increased amounts of slow-wave sleep, or "deep sleep," in women at baseline.

"In women, but not in men, deep sleep appeared to have a protective effect," said Vgontzas. "Women with a higher amount of deep sleep can handle better the effects of one workweek of mild sleep deprivation, and their recovery is more complete after two nights of extended sleep."

According to the American Academy of Sleep Medicine, slow-wave sleep, or deep sleep, is one of the sleep stages that make up a sleep cycle. Each complete cycle lasts about 90 to 110 minutes. Most adults will go through four to six cycles in a full night of sleep. During slow-wave sleep, there is an increase in high-amplitude, slow-wave brain activity, known as delta waves.

The study involved 34 normal sleepers: 16 men and 18 women. They had a mean age of 24.5 years. Participants spent 13 consecutive nights in a sleep lab, sleeping eight hours per night for the first four nights as a baseline measurement. Then sleep was restricted to six hours per night for six nights, followed by three recovery nights of 10 hours of sleep.

Sleepiness was measured subjectively using the Stanford Sleepiness Scale and objectively using the Multiple Sleep Latency Test. Performance was measured using the Psychomotor Vigilance Task. Measurements were taken on the fourth day for baseline data, on day 10 after one week of sleep restriction, and on day 13 after two nights of recovery sleep.

Declines in sleep hygiene across the college years are associated with declines in grade-point average. Although students who are "evening types" initially experience the greatest decline in GPA from high school to college, their grades improve as they shift toward a morning chronotype, suggests a research abstract being presented in Minneapolis, Minn., at SLEEP 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

Results show that poor sleep hygiene was associated with a lower grade-point average in high school. Sleep hygiene worsened upon entering college, and poor sleep hygiene tended to persist through the senior year. Students whose sleep hygiene worsened during college also showed a greater decline in their GPA during college.

According to the American Academy of Sleep Medicine, sleep hygiene involves habits and behaviors that promote healthy sleep. Common examples include establishing a relaxing bedtime routine, and avoiding caffeine in the afternoon and at night.

"Sleep hygiene is a set of voluntary behaviors that you can change," said principal investigator and lead author Jennifer Peszka, PhD, associate professor of psychology at Hendrix College in Conway, Ark. "If they are related to college performance, then students could make small changes that help them do better. It makes sense and we can tell students they need good sleep to help them do well in college, but I think being able to point to empirical data is more convincing."

The study also found differences according to "chronotype," which reflects the time of day when a person prefers to be awake. Students who are "evening types," meaning that they have a natural preference to stay up later at night, showed greater declines in GPA transitioning from high school to college and had a lower freshman GPA (2.84) compared with morning and intermediate types combined (3.18). These night owls shifted significantly more toward a morning chronotype by the senior year of college, when there were no longer significant GPA differences between chronotypes.

"We found that these owls were shifting their clocks during their time in college to be more like morning larks and regular robins," said Peszka. "Perhaps that shift helped their academic performance improve."

Peszka, along with co-authors David Mastin, PhD, from the University of Arkansas at Little Rock and John Harsh, PhD, from the University of Southern Mississippi, studied 89 students who gave access to their high school and college academic records. During the summer before their freshman year of college, they completed a series of questionnaires about their sleep preferences, sleep habits and how they slept in high school.

Thirty-four participants completed the same questionnaires at the end of their freshman year in college, and 43 participants completed the questionnaires after their senior year. Chronotype was identified using the Horne-Ostberg criteria.

The authors concluded that students may be able to improve their academic performance by understanding their chronotype and following sleep hygiene recommendations.

Last year at SLEEP 2010, Peszka, Mastin, Harsh and colleagues reported that poor sleep hygiene was related to higher scores on a measure of perceived stress among college students. Poor sleep hygiene also was associated with higher scores on both the exhaustion and cynicism subscales of a tool that measured "burnout," a state of global exhaustion marked by excessive fatigue, reduced job efficiency and depressed mood.

Short sleep duration may contribute to the development or worsening of hyperactivity and inattention during early childhood, suggests a research abstract that will be presented on June 14, in Minneapolis, Minn., at Sleep 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

Results show that less sleep in preschool-age children significantly predicted worse parent-reported hyperactivity and inattention at kindergarten. In contrast, hyperactivity and inattention at preschool did not predict sleep duration at kindergarten. The sample consisted of approximately 6,860 children, and analyses controlled for gender, ethnicity and family income.

"Children who were reported to sleep less in preschool were rated by their parents as more hyperactive and less attentive compared to their peers at kindergarten," said lead author Erika Gaylor, PhD, senior researcher for SRI International, an independent, nonprofit research institute in Menlo Park, Calif. "These findings suggest that some children who are not getting adequate sleep may be at risk for developing behavioral problems manifested by hyperactivity, impulsivity, and problems sitting still and paying attention."

According to the authors, attention-deficit/hyperactivity disorder is not generally diagnosed until the school-age years. However, the onset of developmentally inappropriate inattention, hyperactivity and impulsivity is often much younger. Sleep problems, particularly difficulty falling asleep and staying asleep, are frequently reported in children and adolescents with ADHD. However, the direction of causation, if any, has been difficult to determine. Longitudinal studies may provide a window into the direction of this complex relationship.

The analyses used data from the preschool and kindergarten waves of the Early Childhood Longitudinal Study — Birth Cohort. The dataset includes a contemporary, representative sample of children and their families living in the U.S. and followed longitudinally from birth through kindergarten entry. Total nighttime sleep duration was calculated using parent-reported bedtimes and wake times, which were obtained via interview at both time points. Parents also rated their children's behavior on brief measures of attention/task persistence and hyperactivity/impulsivity.

Last year at Sleep 2010, Gaylor reported that having a regular bedtime was the most consis¬tent predictor of positive developmental outcomes at 4 years of age. Having an earlier bedtime also was predictive of higher scores for most developmental measures.

 Although a class schedule with later start times allows colleges students to get more sleep, it also gives them more time to stay out drinking at night. As a result, their grades are more likely to suffer, suggests a research abstract that was presented on June 14, in Minneapolis, Minn., at SLEEP 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

Results show that later class start times were associated with a delayed sleep schedule, which led to poorer sleep, more daytime sleepiness, and a lower grade-point average. Students with later class start times also consumed more alcohol and reported more binge drinking. Students who were "night owls" with a natural preference to stay up later were more likely than "morning types" to have a delayed sleep schedule and to consume more alcohol.

"Later class start times predicted more drinking, more sleep time and modestly lower grades, overall," said co-lead author Pamela Thacher, PhD, associate professor in the Department of Psychology at St. Lawrence University in Canton, N.Y. "Later class start times seemed to change the choices students make: They sleep longer, and they drink more."

Thacher speculated that drinking more alcohol, which is known to disrupt sleep, may reduce the benefits of getting more sleep.

"The effects of later class start times might include more sleep," she said. "But this might be offset by lower quality sleep, which in turn might affect their ability to engage, intellectually, with their coursework."

Thacher, co-author Serge Onyper, PhD, and their research team studied 253 college students. Participants completed cognitive tasks and a one-week retrospective sleep diary, as well as questionnaires about sleep, class schedules, substance use and mood. All data were collected on a weekday one month before the end of the semester. GPA was recorded from university records and self-reports.

Results also show that students were attempting to catch up on sleep on the weekends with later rise times and longer sleep durations. Average total sleep time for weekdays and weekends was 8.0 hours.

The authors noted that the results are much different from previous studies of school start times in middle and high school. Those studies show numerous benefits of later school start times, which tend to decrease truancy, improve mood and indirectly promote learning.

In a study published in 2008 in Behavioral Sleep Medicine, Thacher found that 60 percent of student participants at a liberal-arts college reported engaging in a single night of total sleep deprivation once or more since starting college. Statistical analyses found that pulling an "all-nighter" was associated with lower grades.

Treating sleep problems with cognitive-behavioral therapy for insomnia can reduce suicidal ideation, suggests a research abstract that was presented on June 14, in Minneapolis, Minn., at Sleep 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

Results show that about 21 percent of participants with insomnia (65 of 303) reported having suicidal thoughts or wishes during the past two weeks. Group cognitive-behavioral therapy for insomnia produced a statistically significant post-treatment reduction in suicidal ideation. Treatment sessions were conducted weekly until the final two sessions, which were conducted bi-weekly.

According to the authors, a growing body of evidence suggests that self-reported insomnia and poor sleep quality constitute modifiable risk factors for suicide. Sleep complaints also are listed among the top suicide warning signs by the Substance Abuse and Mental Health Service Administration. However, no previous studies had evaluated the impact of a sleep intervention on suicidal ideation.

"This is the first investigation to show that a sleep-targeted intervention has a therapeutic impact on suicide risk specifically," said lead author Rebecca Bernert, PhD, a fellow in the Department of Psychiatry and Behavioral Sciences at Stanford University in California. "This suggests that a treatment focus on sleep disturbances may have important implications for the prevention of suicidal behaviors."

The study involved 303 community outpatients between 18 and 88 years of age who completed group cognitive behavioral therapy for insomnia. The Beck Depression Inventory, which includes a question about suicidal thoughts or wishes, was administered at both baseline and post-treatment.

According to the Centers for Disease Control and Prevention, the most recent data available indicate that the national suicide rate increased from 2008 to 2009, when suicide became the 10th-leading cause of death in the U.S. There were 36,547 deaths attributed to suicide in 2009, which was more than twice as many deaths as those that were attributed to homicide.

Last year at Sleep 2010, Bernert reported that highly variable sleep schedules predicted increases in suicidal risk at one week and three weeks. Sleep irregularity also predicted greater mood lability, which in turn predicted elevated suicidal symptoms.

Individuals experiencing emotional distress or a suicidal crisis are encouraged to call the toll-free National Suicide Prevention Lifeline, a 24-hour crisis hotline, at 1-800-273-TALK.

 Sleep can help college students retain and integrate new information to solve problems on a classroom exam, suggests a research abstract that was presented on June 14, in Minneapolis, Minn., at Sleep 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

Results show that performance by university undergraduates on a microeconomics test was preserved after a 12-hour period that included sleep, especially for cognitively-taxing integration problems. In contrast, performance declined after 12 hours of wakefulness and after a longer delay of one week.

According to the authors, recent sleep research has demonstrated that learned information is often replayed during sleep. This reactivation of learned information may help to consolidate, or stabilize, memories. The present study uniquely extends this area of research to a realistic task that students would encounter in a university classroom.

"Our findings demonstrate the importance of sleep to the ability to flexibly combine distinct concepts to solve novel problems," said lead author Michael Scullin, a doctoral candidate in the Behavior, Brain and Cognition program at Washington University in St. Louis, Mo. "This ability is critical to classroom learning."

The study involved 102 university undergraduates who had never taken an economics course. In the morning or evening they completed an introductory, virtual lecture that trained them on concepts and problems related to supply and demand microeconomics. They were tested on the material either immediately, after a 12-hour period that included sleep, after 12 hours without sleep, or after one week. The test included basic problems that they had been trained to solve, as well as "transfer" problems that required them to integrate their knowledge of supply and demand to solve novel, but related, problems.

"The most surprising finding of our study was that sleep, relative to an equal-length wake interval, benefited performance on the novel, 'transfer' integration problems without affecting performance on the basic, trained problems," said Scullin.

— Sleep duration has a significant association with feelings of external pressure to obtain or maintain a thin body among adolescent girls, especially those who are white, suggests a research abstract being presented in Minneapolis, Minn., at SLEEP 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

Results show that pressures to have a thin body from girlfriends and from the media significantly predict sleep duration and account for 4.5 percent of the variance in hours of sleep for adolescent girls. When results were divided and analyzed by ethnicity, these pressures to be skinny were significantly predictive of sleep duration for white girls, but not for black or Hispanic girls. Together, the two predictors shared six percent of the variance in hours of sleep among white adolescent girls, with the strongest predictor being pressure to be skinny from girlfriends.

"There is a significant amount of research in other areas regarding pressure on adolescent females to minimize body weight, but this pressure as it relates to sleep health is a less-explored topic and its consequences are mostly unknown," said principal investigator Katherine Marczyk, a doctoral student in clinical health psychology and behavioral medicine at the University of North Texas in Denton, Texas. "These results are important as this discovery could be one of the first steps in this research."

Marczyk and co-author Allison Wilkerson led the study, which is a secondary analysis from a larger study led by North Texas professor Trent Petrie, PhD. It involved 789 female middle-school students from a suburban school district in Texas. Their mean age was about 12 years. About 60 percent of participants were white, 26 percent were Hispanic and 10.5 percent were black.

Participants completed the Perceived Sociocultural Pressure Scale, which assesses how much pressure an individual has felt to lose weight and have a thin body. The scale also evaluates the potential sources of this pressure, including peers, friends, family and the media. Sleep was assessed using the Pittsburgh Sleep Quality Index, which is the most commonly used measure of sleep in epidemiological studies. A linear regression was used to assess the degree to which perceived sociocultural pressure predicts hours of sleep.

According to the authors, losing sleep could put adolescent girls at risk for other health problems. In particular, decreased sleep has been linked to increased anxiety and depression.