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Dive into the research topics where Michael Gradisar is active.

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Featured researches published by Michael Gradisar.


Sleep Medicine | 2010

Electronic media use and sleep in school-aged children and adolescents: A review

Neralie Cain; Michael Gradisar

Electronic media have often been considered to have a negative impact on the sleep of children and adolescents, but there are no comprehensive reviews of research in this area. The present study identified 36 papers that have investigated the relationship between sleep and electronic media in school-aged children and adolescents, including television viewing, use of computers, electronic gaming, and/or the internet, mobile telephones, and music. Many variables have been investigated across these studies, although delayed bedtime and shorter total sleep time have been found to be most consistently related to media use. A model of the mechanisms by which media use may affect sleep is presented and discussed as a vehicle for future research.


Sleep | 2011

Time for Bed: Parent-Set Bedtimes Associated with Improved Sleep and Daytime Functioning in Adolescents

Michelle A. Short; Michael Gradisar; Helen Wright; Leon Lack; Hayley Dohnt; Mary A. Carskadon

STUDY OBJECTIVES To determine the proportion of adolescents whose bedtime is set by their parents and to evaluate whether parent-set bedtimes are associated with earlier bedtimes, more sleep, and better daytime functioning. PARTICIPANTS 385 adolescents aged 13-18 years (mean = 15.6, SD = 0.95; 60% male) from 8 socioeconomically diverse schools in South Australia. MEASUREMENTS AND METHODS Adolescents completed the School Sleep Habits Survey during class time and then completed an 8-day Sleep Diary. The Flinders Fatigue Scale was completed on the final day of the study. RESULTS 17.5% of adolescents reported a parent-set bedtime as the main factor determining their bedtime on school nights. Compared to adolescents without parent-set bedtimes, those with parent-set bedtimes had earlier bedtimes, obtained more sleep, and experienced improved daytime wakefulness and less fatigue. They did not differ significantly in terms of time taken to fall asleep. When parent-set bedtimes were removed on weekends, sleep patterns did not significantly differ between groups. CONCLUSIONS Significant personal and public health issues, such as depression and accidental injury and mortality, are associated with insufficient sleep. Converging biological and psychosocial factors mean that adolescence is a period of heightened risk. Parent-set bedtimes offer promise as a simple and easily translatable means for parents to improve the sleep and daytime functioning of their teens.


Sleep Medicine Reviews | 2014

A meta-analysis and model of the relationship between sleep and depression in adolescents: Recommendations for future research and clinical practice

Nicole Lovato; Michael Gradisar

The purpose of this review was to quantify the strength of evidence for a directional relationship between sleep disturbance and depression in adolescents. A literature search was conducted to identify research investigating the relationship between sleep disturbance and depression in adolescent samples (12-20 y). Twenty-three studies were identified; 13 explored associations between depression and sleep disturbance; seven examined the prospective role of sleep disturbance in the development of depression; and three investigated the role of adolescent depression in the development of subsequent sleep disturbance. Average weighted mean differences in sleep/depression-related outcome variables were calculated between adolescents with depression, and non-clinical adolescents, or those in remission. Adolescents with depression experienced significantly more wakefulness in bed (sleep onset latency, wake after sleep onset, number of awakenings and sleep efficiency), lighter sleep (more stage 1), and reported more subjective sleep disturbance. Overall effect sizes from longitudinal and treatment studies suggest sleep disturbance acts as a precursor to the development of depression. At follow-up, depressed adolescents had significantly longer sleep onset, more wake after sleep onset, and lower sleep efficiency compared to adolescents who were non-clinical, or had undergone remission. Little support was found for a predictive role of depressive symptoms in the development of sleep disturbance. Based on these findings we propose a model to understand the development of depression from initial sleep disturbance, provide recommendations for clinicians and recommendations for future research.


Sleep Medicine | 2012

The discrepancy between actigraphic and sleep diary measures of sleep in adolescents

Michelle A. Short; Michael Gradisar; Leon Lack; Helen Wright; Mary A. Carskadon

OBJECTIVE To explore the discrepancy between sleep diary and actigraphic measures of sleep in adolescents and to ascertain whether these discrepancies may vary according to characteristics of the participant. METHODS Participants were 385 adolescents aged 13-18years (X=15.6, standard deviation [SD]=0.95; 60% male) from eight high schools in South Australia. Adolescents completed the School Sleep Habits Survey and Pediatric Daytime Sleepiness Scale during class time, followed by an 8-day sleep diary and wrist actigraphy. The Flinders Fatigue Scale was completed on the final day of the study. Parents completed a sleep, medical, education, and family history survey. RESULTS Actigraphic estimates of wake after sleep onset (WASO) were substantially greater than sleep diary estimates (74min actigraphy vs. 7min sleep diary) and actigraphic estimates of total sleep time were substantially less than sleep diary and parent report (6h 51min actigraphy vs. 8h 16min sleep diary vs. 8h 51 parent report). Actigraphy displayed no significant relationship with daytime functioning and weak relationships with concomitantly recorded sleep diary variables. Sex and puberty-related differences in actigraphic scoring were found, with more WASO and less sleep scored in boys compared to girls and more WASO scored amongst pubertally-mature boys than boys of less advanced pubertal development. CONCLUSIONS There may be differences in the sleep of adolescents that result in less actigraphic total sleep scored than perceived, particularly in boys, possibly because of increased sleep motor activity in adolescents that actigraphic algorithms score as wake. This is a significant concern that requires further examination with polysomnography.


Journal of Adolescence | 2013

The impact of sleep on adolescent depressed mood, alertness and academic performance

Michelle A. Short; Michael Gradisar; Leon Lack; Helen Wright

The present study developed and tested a theoretical model examining the inter-relationships among sleep duration, sleep quality, and circadian chronotype and their effect on alertness, depression, and academic performance. Participants were 385 adolescents aged 13-18 years (M = 15.6, SD = 1.0; 60% male) were recruited from eight socioeconomically diverse high schools in South Australia. Participants completed a battery of questionnaires during class time and recorded their sleep patterns in a sleep diary for 8 days. A good fit was found between the model and the data (χ(2)/df = 1.78, CFI = .99, RMSEA = .04). Circadian chronotype showed the largest association with on adolescent functioning, with more evening-typed students reporting worse sleep quality (β = .50, p < .001) and diminished alertness (β = .59, p < .001). Sleep quality was significantly associated with poor outcomes: adolescents with poorer sleep quality reported less sleep on school nights (β = -.28, p < .001), diminished daytime alertness (β = .33, p < .001), and more depressed mood (β = .47, p < .001). Adolescents with poor sleep quality and/or more evening chronotype were also more likely to report worse grades, through the association with depression. Sleep duration showed no direct effect on adolescent functioning. These results identified the importance of two lesser-studied aspects of sleep: circadian chronotype and sleep quality. Easy-to-implement strategies to optimize sleep quality and maintain an adaptive circadian body clock may help to increase daytime alertness, elevate mood, and improve academic performance.


Sleep Medicine | 2012

Is shortened sleep duration a risk factor for overweight and obesity during adolescence? A review of the empirical literature

Matthew Guidolin; Michael Gradisar

This paper reviews 15 adolescent (10-19 yrs) studies that have directly investigated the effects of shortened sleep duration on overweight and obesity. The research studies included in this review inconsistently found significant effects between shortened sleep duration and weight status. This heterogeneity in study findings largely resulted from variability in study design, gender, and the method used to measure sleep duration. Consequently, due to the conflicting research findings, it remains inconclusive as to whether shortened sleep is a risk factor for overweight or obesity during adolescence. This review also identified methodological limitations within the literature and presented alternative methodologies for future research. First, sleep duration measures were identified that had questionable reliability and were possibly less accurate than other recommended sleep measurements. Second, 92% of cross-sectional studies found a significant relationship, yet 0% of prospective studies did. Third, the vast majority of studies neglected to statistically adjust for co-contributions from depression, and approximately half of the studies considered the role of physical activity. Recommendations for future research directions are presented which may help to clarify the conflicting findings and address the methodological concerns identified within this topical area.


Journal of Clinical Psychology | 2012

Cognitive‐Behavioral Approaches to Outpatient Treatment of Internet Addiction in Children and Adolescents

Daniel L. King; Paul Delfabbro; Mark D. Griffiths; Michael Gradisar

Excessive and potentially addictive use of the Internet among children and adolescents has emerged as a major concern in recent times. Internet addiction is often conceptualized as an impulse control disorder, with features similar to pathological gambling. However, there remains considerable debate about the core components, etiological processes, course, and maintaining factors of the disorder. This article presents a case study of a 16-year-old male with generalized pathological Internet use. Critical issues relevant to case conceptualization, assessment, and choice of therapy are examined. Although the evidence base is limited in this emerging area of clinical psychology, we provide a summary of empirically supported cognitive-behavioral techniques for Internet addiction.


Nature and Science of Sleep | 2013

Estimating adolescent sleep patterns: parent reports versus adolescent self-report surveys, sleep diaries, and actigraphy

Michelle A. Short; Michael Gradisar; Leon Lack; Helen Wright; Alex Chatburn

Background In research and clinical contexts, parent reports are often used to gain information about the sleep patterns of their adolescents; however, the degree of concordance between parent reports and adolescent-derived measures is unclear. The present study compares parent estimates of adolescent sleep patterns with adolescent self-reports from surveys and sleep diaries, together with actigraphy. Methods A total of 308 adolescents (59% male) aged 13–17 years completed a school sleep habits survey during class time at school, followed by a 7-day sleep diary and wrist actigraphy. Parents completed the Sleep, Medical, Education and Family History Survey. Results Parents reported an idealized version of their adolescent’s sleep, estimating significantly earlier bedtimes on both school nights and weekends, significantly later wake times on weekends, and significantly more sleep than either the adolescent self-reported survey, sleep diary, or actigraphic estimates. Conclusion Parent reports indicate that the adolescent averages a near-optimal amount of sleep on school nights and a more than optimal amount of sleep on weekends. However, adolescent-derived averages indicate patterns of greater sleep restriction. These results illustrate the importance of using adolescent-derived estimates of sleep patterns in this age group and the importance of sleep education for both adolescents and their parents.


Journal of Adolescence | 2013

The Sleep Patterns and Well-Being of Australian Adolescents.

Michelle A. Short; Michael Gradisar; Leon Lack; Helen Wright; Hayley Dohnt

AIM Adolescent sleep patterns vary between countries, and these differences influence adolescent functioning and well-being. The present study provides data on the sleep and well-being of Australian adolescents. METHODS 385 adolescents aged 13-18 years were recruited from 8 South Australian schools spanning the socio-economic spectrum. Adolescents completed survey battery during class time at school, followed by a 7-day sleep diary. RESULTS Australian adolescents, on average, obtained inadequate sleep across the school week. Adolescents commonly reported difficulty initiating sleep, unrefreshing sleep, and the subjective feeling of restless legs. Problematic levels of sleepiness, fatigue, depressed mood and anxiety were highly prevalent. Later bedtimes, longer sleep onset latencies, and shorter sleep duration were significantly associated with aspects of poor daytime functioning. CONCLUSION These results add to our knowledge of adolescent sleep and well-being worldwide. They also highlight the need for greater attention to sleep during this phase of development, when future behaviors and outcomes are being shaped.


Behaviour Research and Therapy | 2009

The sleep patterns and problems of clinically anxious children

Jennifer L. Hudson; Michael Gradisar; Amanda L. Gamble; Carolyn A. Schniering; Ivone Rebelo

Childhood sleep problems have been associated with a range of adverse cognitive and academic outcomes, as well as increased impulsivity and emotional disorders such as anxiety and depression. The aim of the study was to examine subjective reports of sleep-related problems in children with anxiety disorders during school and weekend nights. Thirty-seven children with clinically-diagnosed anxiety disorders and 26 non-clinical children aged 7-12 years completed an on-line sleep diary to track sleep patterns across school nights and weekend nights. Anxious children reported going to bed significantly later (p=0.03) and had significantly less sleep (p=0.006) on school nights compared to non-anxious children. No significant differences in sleep onset latency, number of awakenings or time awake during the night, daytime sleepiness, or fatigue were found between the two groups. On the weekends, anxious children fell asleep quicker and were less awake during the night than on weeknights. School-aged anxiety disordered children showed a sleep pattern that differs from their non-anxious peers. Although the mean 30 min less sleep experienced by anxious children may initially seem small, the potential consequences on daytime performance from an accumulation of such a sleep deficit may be significant, and further investigation is warranted.

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