Author
Sakari Lemola
Other affiliations: University of Helsinki, University of Basel, University of Warwick
Bio: Sakari Lemola is an academic researcher from Bielefeld University. The author has contributed to research in topics: Medicine & Slow-wave sleep. The author has an hindex of 29, co-authored 87 publications receiving 2796 citations. Previous affiliations of Sakari Lemola include University of Helsinki & University of Basel.
Topics: Medicine, Slow-wave sleep, Sleep disorder, Low birth weight, Sleep onset
Papers published on a yearly basis
Papers
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TL;DR: Electronic media use was negatively related with sleep duration and positively with sleep difficulties, which in turn were related to depressive symptoms, and sleep difficulties were the more important mediator than sleep duration.
Abstract: Adolescence is a time of increasing vulnerability for poor mental health, including depression. Sleep disturbance is an important risk factor for the development of depression during adolescence. Excessive electronic media use at night is a risk factor for both adolescents’ sleep disturbance and depression. To better understand the interplay between sleep, depressive symptoms, and electronic media use at night, this study examined changes in adolescents’ electronic media use at night and sleep associated with smartphone ownership. Also examined was whether sleep disturbance mediated the relationship between electronic media use at night and depressive symptoms. 362 adolescents (12–17 year olds, M = 14.8, SD = 1.3; 44.8 % female) were included and completed questionnaires assessing sleep disturbance (short sleep duration and sleep difficulties) and depressive symptoms. Further, participants reported on their electronic media use in bed before sleep such as frequency of watching TV or movies, playing video games, talking or text messaging on the mobile phone, and spending time online. Smartphone ownership was related to more electronic media use in bed before sleep, particularly calling/sending messages and spending time online compared to adolescents with a conventional mobile phone. Smartphone ownership was also related to later bedtimes while it was unrelated to sleep disturbance and symptoms of depression. Sleep disturbance partially mediated the relationship between electronic media use in bed before sleep and symptoms of depression. Electronic media use was negatively related with sleep duration and positively with sleep difficulties, which in turn were related to depressive symptoms. Sleep difficulties were the more important mediator than sleep duration. The results of this study suggest that adolescents might benefit from education regarding sleep hygiene and the risks of electronic media use at night.
602 citations
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TL;DR: The findings show that great day-to-day variability in sleep duration – more than averageSleep duration – is related to poor subjective sleep quality and poor subjective well-being.
Abstract: While there is a large body of evidence that poor subjective sleep quality is related to lower subjective well-being, studies on the relation of objective sleep measures and subjective well-being are fewer in number and less consistent in their findings. Using data of the Survey of Mid-Life in the United States (MIDUS), we investigated whether duration and quality of sleep, assessed by actigraphy, were related to subjective well-being and whether this relationship was mediated by subjective sleep quality. Three hundred and thirteen mainly white American individuals from the general population and 128 urban-dwelling African American individuals between 35 and 85 years of age were studied cross-sectionally. Sleep duration, variability of sleep duration, sleep onset latency, and time awake after sleep onset were assessed by actigraphy over a period of 7 days. Subjective sleep quality was assessed with the Pittsburgh Sleep Quality Index, positive psychological well-being and symptoms of psychological distress were assessed with the Satisfaction with Life Scale and the Mood and Anxiety Symptom Questionnaire. In both white and African Americans high day-to-day variability in sleep duration was related to lower levels of subjective well-being controlling age, gender, educational and marital status, and BMI. By contrast, sleep duration, sleep onset latency, and time awake after sleep onset were not related to subjective well-being controlling covariates and other sleep variables. Moreover, the relationship between variability in sleep duration and well-being was partially mediated by subjective sleep quality. The findings show that great day-to-day variability in sleep duration – more than average sleep duration – is related to poor subjective sleep quality and poor subjective well-being.
232 citations
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TL;DR: Consistent across the two samples, mental toughness mitigated the relationship between high stress and depressive symptoms, and the interaction between stress and mental toughness explained 2% of variance in the adolescent sample and 10%" of variance among young adults.
Abstract: Mental toughness has been explored predominantly within sport contexts. Nevertheless, it is difficult to conceive mental toughness as only applicable to athletes. This study examines whether mentally tough participants exhibit resilience against stress. This is a cross-sectional study based on two different samples: Sample 1 consisted of 284 high school students (99 males, 185 females, M = 18.3 years). Sample 2 consisted of 140 first through fifth semester undergraduate students (53 males, 87 females, M = 20.0 years). Participants provided information about their level of perceived stress (10-item Perceived Stress Scale), mental toughness (48-item Mental Toughness Questionnaire) and depressive symptoms (Beck Depression Inventory). Consistent across the two samples, mental toughness mitigated the relationship between high stress and depressive symptoms. The interaction between stress and mental toughness explained 2% of variance in the adolescent sample and 10% of variance among young adults. The promotion of protective factors that foster resilient adaptation is a relevant issue. Mental toughness may appeal to individuals that are typically difficult to be reached with health interventions. Because mental toughness is part of young people's daily speech, it may serve as a less academic resource than other health psychology concepts.
136 citations
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TL;DR: This study is the first to provide empirical evidence that the German version of the Insomnia Severity Index has good psychometric properties and satisfactory convergent and factorial validity across various age groups and both men and women.
Abstract: A variety of objective and subjective methods exist to assess insomnia. The Insomnia Severity Index (ISI) was developed to provide a brief self-report instrument useful to assess people’s perception of sleep complaints. The ISI was developed in English, and has been translated into several languages including German. Surprisingly, the psychometric properties of the German version have not been evaluated, although the ISI is often used with German-speaking populations. The psychometric properties of the ISI are tested in three independent samples: 1475 adolescents, 862 university students, and 533 police and emergency response service officers. In all three studies, participants provide information about insomnia (ISI), sleep quality (Pittsburgh Sleep Quality Index), and psychological functioning (diverse instruments). Descriptive statistics, gender differences, homogeneity and internal consistency, convergent validity, and factorial validity (including measurement invariance across genders) are examined in each sample. The findings show that the German version of the ISI has generally acceptable psychometric properties and sufficient concurrent validity. Confirmatory factor analyses show that a 1-factor solution achieves good model fit. Furthermore, measurement invariance across gender is supported in all three samples. While the ISI has been widely used in German-speaking countries, this study is the first to provide empirical evidence that the German version of this instrument has good psychometric properties and satisfactory convergent and factorial validity across various age groups and both men and women. Thus, the German version of the ISI can be recommended as a brief screening measure in German-speaking populations.
127 citations
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TL;DR: Examination of the relationship of sleep duration with positive attitude toward life and academic achievement in a sample of 2716 adolescents in Switzerland found students who started school 20 min later received reliably more sleep and reported less tiredness.
127 citations
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TL;DR: This article summarizes the research on the positive effects of playing video games, focusing on four main domains: cognitive, motivational, emotional, and social, and proposes some candidate mechanisms by which playing videoGames may foster real-world psychosocial benefits.
Abstract: Video games are a ubiquitous part of almost all children's and adolescents' lives, with 97% playing for at least one hour per day in the United States. The vast majority of research by psychologists on the effects of "gaming" has been on its negative impact: the potential harm related to violence, addiction, and depression. We recognize the value of that research; however, we argue that a more balanced perspective is needed, one that considers not only the possible negative effects but also the benefits of playing these games. Considering these potential benefits is important, in part, because the nature of these games has changed dramatically in the last decade, becoming increasingly complex, diverse, realistic, and social in nature. A small but significant body of research has begun to emerge, mostly in the last five years, documenting these benefits. In this article, we summarize the research on the positive effects of playing video games, focusing on four main domains: cognitive, motivational, emotional, and social. By integrating insights from developmental, positive, and social psychology, as well as media psychology, we propose some candidate mechanisms by which playing video games may foster real-world psychosocial benefits. Our aim is to provide strong enough evidence and a theoretical rationale to inspire new programs of research on the largely unexplored mental health benefits of gaming. Finally, we end with a call to intervention researchers and practitioners to test the positive uses of video games, and we suggest several promising directions for doing so.
1,546 citations
01 Jan 2008
TL;DR: This work reviews the literature regarding short sleep duration as an independent risk factor for obesity and weight gain and suggests sleep deprivation may influence weight through effects on appetite, physical activity, and/or thermoregulation.
Abstract: Objective: The recent obesity epidemic has been accompanied by a parallel growth in chronic sleep deprivation. Physiologic studies suggest sleep deprivation may influence weight through effects on appetite, physical activity, and/or thermoregulation. This work reviews the literature regarding short sleep duration as an independent risk factor for obesity and weight gain.
1,172 citations
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TL;DR: High frequency of mobile phone use at baseline was a risk factor for mental health outcomes at 1-year follow-up among the young adults, and the risk for reporting mental health symptoms at follow- up was greatest among those who had perceived accessibility via mobile phones to be stressful.
Abstract: Background
Because of the quick development and widespread use of mobile phones, and their vast effect on communication and interactions, it is important to study possible negative health effects of mobile phone exposure. The overall aim of this study was to investigate whether there are associations between psychosocial aspects of mobile phone use and mental health symptoms in a prospective cohort of young adults.
929 citations