The authors propose that broad aspects of lateral relationships, conceptualized as coworker support and coworker antagonism, are linked to important individual employee outcomes (role perceptions, work attitudes, withdrawal, and effectiveness) in a framework that synthesizes several theoretical predictions. From meta-analytic tests based on 161 independent samples and 77,954 employees, the authors find support for most of the proposed linkages. Alternative explanations are ruled out, as results hold when controlling for leader influences and mediation processes. The authors also observe differential strengths of coworker influence based on its valence, content, and severity, and on the social intensity of the task environment. The authors conclude with a call for more comprehensive, complex theory and investigation of coworker influences as part of the social environment at work.

Do Peers Make the Place? Conceptual Synthesis and Meta-Analysis of Coworker Effects on Perceptions, Attitudes, OCBs, and Performance

Do peers make the place? Conceptual synthesis and meta-analysis of coworker effects on perceptions, attitudes, OCBs, and performance.

Jet lag: trends and coping strategies

Many processes in the human body — including brain function — are regulated over the 24-hour cycle, and there are strong associations between disrupted circadian rhythms (for example, sleep–wake cycles) and disorders of the CNS. Brain disorders such as autism, depression and Parkinson disease typically develop at certain stages of life, and circadian rhythms are important during each stage of life for the regulation of processes that may influence the development of these disorders. Here, we describe circadian disruptions observed in various brain disorders throughout the human lifespan and highlight emerging evidence suggesting these disruptions affect the brain. Currently, much of the evidence linking brain disorders and circadian dysfunction is correlational, and so whether and what kind of causal relationships might exist are unclear. We therefore identify remaining questions that may direct future research towards a better understanding of the links between circadian disruption and CNS disorders.

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Rhythms of life: circadian disruption and brain disorders across the lifespan.

Societal costs of insomnia.

Job stress, social support, and prevalence of insomnia in a population of Japanese daytime workers.

A cross-sectional study was conducted to evaluate the contribution of daily sleep habits and depressive symptoms to sickness absences of shift workers. A self-administered questionnaire that solicited answers about sleep, symptoms of depression, sickness absence, diseases/injuries, and lifestyle factors was submitted to a sample of 522 rotating shift workers between the ages of 18–59 (mean 27) yrs of an electric equipment manufacturing company. The seven features of sleep queried were daily hours of sleep, time to fall asleep, awakening during sleep, early morning awakening, sleep well at night, sufficiency of sleep, and excessive daytime sleepiness at work. The responses were assessed over the subject's previous 1-yr period. Each sleep feature, except daily sleeping hours, was dichotomized by the following responses: (1) taking more than 30 min to fall asleep (difficulty initiating sleep; DIS), (2) awakening during sleep almost every day (difficulty maintaining sleep; DMS), (3) early morning awakening al...

Association of sickness absence with poor sleep and depressive symptoms in shift workers.

A worksite study was conducted to examine whether a 15-min nap during a post-lunch rest period would affect subsequent alertness, performance, and nocturnal sleep in eight factory workers under a 3-week protocol. Subjects were asked to take the nap at 12:30 h on a reclining chair during the nap week, and to remain awake during the no-nap week. The order of these 2 weeks was counterbalanced between the subjects. During the third, follow-up week, each subject determined whether or not she/he would nap. Alertness on the job and nocturnal sleep were assessed using a sleep diary. Wrist activity was also recorded during sleep at night. Choice reaction time task (RT) was performed at 10:00 and 15:00 h every day of the nap week and every other day of the no-nap and follow-up weeks. Perceived alertness was significantly higher in the afternoon after nap than after no nap at the end of the week. Similar effects were observed during the follow-up week where almost half of the subjects napped. No significant differences between the three weeks were found for RT performance or nocturnal sleep. Workers' attitudes toward the nap were favourable. Although further intervention research is required, our results suggest that post-lunch napping may have the potential to promote daytime alertness at work.

Post-lunch nap as a worksite intervention to promote alertness on the job

A cross-sectional study was conducted to clarify the contribution of psychological job stress to insomnia in shift workers. A self-administered questionnaire concerning job stress, sleep, depressive symptoms and lifestyle factors was submitted to a sample of 530 rotating shift workers of age 18-59 years (mean age 27) in an electric equipment manufacturing company. Perceived job stress, i.e., job demands, job control and social support at work, was assessed using the Japanese version of the Job Content Questionnaire. Insomnia was regarded as prevalent if the workers had at least one of the following symptoms in the last year; less than 30 minutes to fall asleep, difficulty in maintaining sleep, or early morning awakening almost everyday. Overall prevalence was 37.8%. Logistic regression analyses while adjusting relevant factors showed that lower social support at work was significantly associated with a greater risk of insomnia than the higher social support (adjusted OR 2.5). Higher job strain with lower social support at work increased the risk, compared to lower strain with higher support at work (crude OR 1.8; adjusted OR 1.5). Our findings suggest the low social support at work independently associated with insomnia in shift workers.

Job stress, social support at work, and insomnia in Japanese shift workers.

Objectives. To examine variations in sleep and wakefulness associated with international travel. Methods. Ten academics in Japan were studied while traveling abroad to participate in conferences. Wrist activity and a daily log were recorded continuously for 1 week before, during, and for 1 week after travel. Destinations included the USA and Canada to the east (8 to 11-h time difference; mean stay of 6.8 days) and Europe to the west (7 to 8-h time difference; mean stay of 6.0 days). Results. For eastward-traveling subjects, the total sleep time was shorter and the mean activity during sleep was greater at the destinations than before departure. These sleep disruptions persisted until the 2nd day after the subjects had returned home. The sleep patterns then recovered in a zigzag manner. No significant disruptions in the main sleep were found in westward travelers, although these subjects took a longer nap immediately after their return. The beginning and end of sleep occurred earlier until the 2nd day after the subjects had returned from eastward trips, but occurred later until the 5th day after return from westward trips. Conclusions. In academics, short-term international travel causes sleep disturbances both during and at home after eastward travel and a delay in the sleep timing at home after westward travel. Although the subjects in this study might be atypical of business travelers, the current data suggest that strategies are needed to facilitate recovery from disturbed sleep–wake patterns at home after travel, i.e., redesign of post-travel work schedules.

Heihachiro Arito

Papers

Job stress, social support, and prevalence of insomnia in a population of Japanese daytime workers.

Association of sickness absence with poor sleep and depressive symptoms in shift workers.

Post-lunch nap as a worksite intervention to promote alertness on the job

Job stress, social support at work, and insomnia in Japanese shift workers.

Disturbed sleep-wake patterns during and after short-term international travel among academics attending conferences.