Results showed that patients with primary insomnia had increased brain activation relative to good sleepers during the working memory task, particularly in areas responsible for visual-spatial attention and coordination of cognitive processes. This activation may explain how patients with primary insomnia maintain performance on the task despite their sleep difficulties. People with primary insomnia also were found to have decreased activation in visual and motor areas, suggesting they might have higher baseline activation in these regions relative to good sleepers.
According to principal investigator Henry Orff, MS, at the University of California, San Diego, these findings show that people with primary insomnia, similar to individuals who are acutely sleep-deprived, may be able to maintain performance on different tasks if they are able to compensate with increased brain activation.
“The good news is that patients with insomnia are probably able to function well in their daily lives and likely do not show significantly impaired performance,” said Mr. Orff. “That said, patients may have to work, concentrate, and attend more to tasks than people who sleep well.”
The authors stated that they do not know yet whether the findings suggest potential long-term implications for cognitive functioning if primary insomnia is left untreated.
Genetic Link Found Between Stress-Induced Sleep Loss and Intrusive Thinking
The genetic factors that cause increased sleep problems during times of stress seem to be the same as those that make people with intrusive and ruminative thoughts have a higher prevalence of insomnia, according to results of a twin study.
The study included 1,782 individual twins (1,059 females) between the ages of 18 and 30. Genetic analyses included 744 complete twin pairs (377 monozygotic and 367 dizygotic). Participants completed an online sleep survey and questionnaires that measured sleep response to stress, frequency of intrusive thoughts, and frequency and severity of three insomnia symptoms (difficulty falling asleep, staying asleep, and nonrefreshing sleep). Females included in the study had a higher prevalence of insomnia, more frequent intrusive thoughts, and higher sleep reactivity to stress. The degree to which genetics influenced each of these traits was not significantly different for males and females, and the relationships among these variables were similar for males and females.
Results indicated that sleep reactivity to stress mediates the genetic relationship between ruminative thoughts and insomnia. According to Naomi Friedman, PhD, Senior Research Associate at the Institute for Behavioral Genetics at the University of Colorado at Boulder, the findings of shared environmental influences on intrusive thinking, sleep reactivity to stress, and insomnia confirm previous research showing that it may be beneficial for people with higher reactivity to stress and/or ruminators to try and modify their environments to minimize their stress levels. Individuals with ruminative tendencies should attempt to determine the particularly stressful environmental influences that trigger thoughts that can interfere with their sleep.
“Identification of genes underlying the association between sleep reactivity to stress and intrusive thinking and ruminative tendencies may enable the development of more targeted pharmacologic interventions for insomnia,” said Dr. Friedman. “At the nonpharmacologic level, behavioral treatments could be designed to target specific aspects underlying a tendency toward rumination in the individual across many potential environmental triggers.”
A Bidirectional Relationship Is Observed Between Chronic Stress and Sleep Problems
Patients with chronic stress report shorter sleep duration, worse sleep quality, and more daytime functioning impairments. Conversely, daytime functioning impairments and shorter sleep duration demonstrated a predictive relationship with habitual stress complaints, reported Eric Powell, PhD, Director of Research at the Research Center, Clayton Sleep Institute, in St. Louis.
The study included data from 544 patients at the Midwestern metropolitan sleep center who received diagnostic polysomnograms. Participants ranged in age from 18 to 79, were not shift workers, and had no prior sleep disorder diagnosis. Subjects completed a brief estimate of their state and trait stress, and sleepiness was assessed subjectively; individuals were divided into low- and high-trait stress groups.
Results indicate that poor sleep may be a potential cause of stress, and individuals who report more fatigue and less total sleep are more likely to report more stress. According to Dr. Powell, the best predictors of high stress were daytime functioning and typical amount of sleep.
“The simplest, and likely best, advice for individuals with high stress and poor sleep is to look at some of the lifestyle choices they are making, and ensuring sufficient sleep is at the core of those choices,” said Dr. Powell.
A Link Is Found Between Poor Sleep Quality and Increased Risk of Death in Middle-Aged and Older Adults
Quality, in addition to quantity, is important for maintaining health, according to Alison Laffan, PhD, a postdoctoral fellow at the California Pacific Medical Center in San Francisco. Increasing evidence from a number of studies has shown that poor sleep increases risk for adverse health outcomes, she said.