Michael Gradisar

• M.Psych.(Clin.) / PhD
• Professor at WINK Sleep Pty Ltd

The link between technology and sleep is more complex than originally thought. In this updated theoretical review, we propose a new model informed by the growing body of evidence in the area over the past 10 years. The main theoretical change is the addition of bi-directional links between the use of technology and sleep problems. We begin by revie...

Epidemiological studies show a high prevalence of "insomnia" in adolescents. However, insomnia symptoms are not specific for insomnia disorder. Puberty is associated with circadian delay, which may cause insomnia symptoms such as problems falling asleep and daytime impairments, but also difficulties rising in the morning which is not a hallmark of...

Adolescent sleep quality and quantity is commonly linked to worse emotion regulation. One maladaptive emotion regulation strategy that is on the rise is non-suicidal self-injury (NSSI), which includes burning, hitting, or scratching one’s own body tissue without suicidal intent. The aim of this study was to explore the frequency of NSSI among diffe...

This study explored the prospective associations between sleep patterns, mental health and registry‐based school grades among older adolescents. In the spring of 2019, 1st year high‐school students in Western Norway were invited to a survey assessing habitual sleep duration, insomnia, depression and anxiety. Sleep patterns, depression and anxiety w...

Alcohol is a significant contributor to the world's burden of disease. The COVID-19 pandemic saw many governments impose lockdowns yet list liquor stores as an essential service. Data from 2020 already show a rise in alcohol consumption and alcohol-related deaths. The present study evaluated an online 30-day program aimed at reducing alcohol consum...

Objective Sleep problems constitute a common and heterogeneous complaint in pediatric palliative care (PPC), where they often contribute to disease morbidity and cause additional distress to children and adolescents and their families already facing the burden of life-threatening and life-limiting conditions. Despite the significant impact of slee...

The COVID-19 pandemic has seen a rise in anxiety and depression among adolescents. This study aimed to investigate the longitudinal associations between sleep and mental health among a large sample of Australian adolescents and examine whether healthy sleep patterns were protective of mental health in the context of the COVID-19 pandemic. We used t...

Introduction: During adolescence, peers gain a central role and with the availability of technology, socializing can occur around the clock. Very few studies have focused on the role of peers in adolescents’ sleep using social network analyses. These analyses describe peer relationships and social positions in a defined context (e.g., school) based...

Background Insomnia and eveningness are common and often comorbid conditions in youths. While cognitive behavioural therapy for insomnia (CBT-I) has been suggested as a promising intervention, it remains unclear whether it is sufficient to also address circadian issues in youths. In addition, despite that light has been shown to be effective in pha...

The overall aim of the present study was to examine the daily patterns and relationships between sleep behavior, anxiety, mood (i.e., depression symptoms) and cognitive performance (i.e., reaction time) in esports athletes competing in an Oceanic Rocket League Championship Series regional event. Sixteen participants completed a daily sleep diary, e...

Infant sleep problems have been associated with a myriad of adverse child and parent outcomes, yet whether these problems may pose a risk for parents on the road has received little research attention. This study sought to test whether mothers of infants with insomnia are at an elevated risk for vehicular crashes, by comparing their objectively mea...

Introduction The COVID-19 pandemic has seen a rise in emotional problems among adolescents. Improving young people's mental health is a public health priority, and examining protective factors throughout the pandemic can offer insights on targets for prevention. This study aimed to investigate longitudinal trajectories of depressive and anxiety sym...

Background: Adolescents’ sleep does not occur in isolation from their social context. During adolescence, peers gain a central role and with the availability of technology, socializing can occur around the clock. Very few studies have focused on the role of the peer context in adolescents’ sleep problems using social network analyses (Mednick et al...

This study tested the efficacy of a 5 × 1.5 h/session, group-based, parent-focused, behavioural intervention (BI) targeting sleep problems in preschool children. Parents were randomised to either the BI (N = 62) or care as usual (CAU; N = 66) conditions. Outcomes included sleep, anxiety, behavioural problems, internalising and externalising symptom...

The physiological processes governing sleep regulation show maturational changes during adolescent development. To date, data are available to specify when delays in circadian timing occur; however, no longitudinal data exist to characterize the maturation of the accumulation of sleep pressure across the evening. The aim of this longitudinal study...

Introduction Despite the efficacy of cognitive behavioural therapy for insomnia (CBT-I) for treating youth insomnia, there remain individual differences in treatment outcomes. Previous studies found that demographic (e.g., age) and clinical features (e.g., depression, anxiety) could potentially affect treatment responses in adults but there has bee...

This study investigated how changing or maintaining parent-set bedtimes over time relates to adolescents’ sleep timing, latency, and duration. Adolescents (n = 2509; Mage = 12.6 [0.5] years; 47% m) self-reported their sleep patterns, and whether they had parent-set bedtimes on two separate occasions in 2019 (T1; 12.6 years) and 2020 (T2; 13.7 years...

Study objectives: Infant sleep problems are one of the most common complaints of new parents. Research to date has demonstrated a relationship between low parental cry tolerance and infant sleep problems. The aim of this study was to explore whether three emotion regulation strategies could increase parental cry tolerance. Methods: This study ut...

Background Previous studies have suggested that parental cognitions about child's sleep may be an important factor underlying pediatric sleep problems. The current study aimed to (a) develop an assessment tool measuring parental understanding and misperceptions about baby's sleep (PUMBA‐Q); (b) validate the questionnaire using self‐report and objec...

The present study investigated the influence and perspective of esports coaches and support staff on the sleep habits of esports athletes competing at professional and semiprofessional levels. Eighty-four esports coaches and support staff from 19 countries completed an online questionnaire. The first section obtained demographic information. The se...

This White Paper addresses the current gaps in knowledge, as well as opportunities for future studies in pediatric sleep. The Sleep Research Society's Pipeline Development Committee assembled a panel of experts tasked to provide information to those interested in learning more about the field of pediatric sleep, including trainees. We cover the sco...

Study Objectives The aim of this study was to; 1) explore whether adolescents use technology as distraction from negative thoughts before sleep, 2) assess whether adolescents who perceive having a sleep problem use technology as distraction more compared to adolescents without sleep complaints, 3) collect qualitative information about which devices...

Objectives To compare the real-world frequency, timing, duration, difficulty, and helpfulness of three infant Behavioral Sleep Intervention (BSI) approaches: Unmodified Extinction, Modified Extinction, and Parental Presence, and to examine the effectiveness and safety of these approaches by comparing infant sleep, parent sleep, daytime sleepiness,...

Background. Changing lifestyles and the widespread use of artificial lighting have contributed to the disruption of circadian rhythms in modern society. As various aspects of affect and cognition are also controlled by circadian rhythms, this is of concern. Thus, circadian phase assessment is increasingly applied in the diagnostic process in clinic...

One of the most prevalent sleep disorders in children and adolescents is "insomnia," which can be briefly described as problems with initiating and/or maintaining sleep with associated daytime consequences. These are typical insomnia symptoms, and when experienced for long enough and when they interfere with an important area of the young person's...

Objective: This study tested the efficacy of a group-based, parent-focused, behavioural sleep intervention (BI) targeting insomnia in preschool children. Methods: Parents of children in the year prior to formal schooling were randomized to either the BI condition or a care as usual (CAU) condition. Outcomes included sleep, anxiety, behavioural prob...

Light is a potent circadian entraining agent. For many people, daily light exposure is fundamentally dysregulated with reduced light during the day and increased light into the late evening. This lighting schedule promotes chronic disruption to circadian physiology resulting in a myriad of impairments. Developmental changes in sleep-wake physiology...

This study investigated the associations between adolescent evening use of technology devices and apps, night time sleep, and daytime sleepiness. Participants were 711 adolescents aged 12–18 years old (46% Female, Mage = 15.1, SD = 1.2). Time spent using technology devices and apps in the hour before bed, and in bed before sleep onset, was self-rep...

The postpartum period may pose a considerable challenge for both parent sleep and sexual activity. This study assessed the links between partnered sexual frequency and satisfaction postpartum and parent sleep, infant sleep, parent nighttime caregiving, and parent-infant room sharing. Participants were 897 parents of infants aged 1-18-months (M = 8....

Study Objectives. During adolescence, an interplay between biological and environmental factors leads to constrained sleep duration and timing. The high prevalence of sleep deprivation during this developmental period is a public health concern, given the value of restorative sleep for mental, emotional, and physical health. One of the primary cont...

Study objectives The day-to-next day predictions between physical activity (PA) and sleep are not well known, although they are crucial for advancing public health by delivering valid sleep and physical activity recommendations. We used Big Data to examine cross-lagged time-series of sleep and PA over 14 days and nights. Methods Bi-directional cro...

Sleep restriction therapies likely drive improvement in insomnia in middle childhood via increases in homeostatic sleep pressure (e.g., evening sleepiness). Increased evening sleepiness may also dampen comorbid anxiety symptoms; and reduced wakefulness in bed may reduce worry. However, sleep restriction therapies have never been evaluated as a stan...

Two adolescent mental health fields — sleep and depression — have advanced largely in parallel until about four years ago. Although sleep problems have been thought to be a symptom of adolescent depression, emerging evidence suggests that sleep difficulties arise before depression does. In this Review, we describe how the combination of adolescent...

Study Objectives We examined how adolescents’ sleep patterns (i.e., insomnia symptoms and sleep duration) change from early- to mid-adolescence and whether adolescents follow different trajectories. Further, we also examined the characteristics of adolescents within different trajectories, with a specific focus on the role of school-related stress....

Study Objectives We examined how adolescents’ sleep patterns (i.e., insomnia symptoms and sleep duration) change from early- to mid-adolescence and whether adolescents follow different trajectories. Further, we also examined the characteristics of adolescents within different trajectories, with a specific focus on the role of school-related stress....

There is limited evidence surrounding the relationship between parent-set technology rules and adolescent sleep. This study had two aims: 1) to investigate the relationship between presence of and compliance to parent-set technology rules and adolescent sleep outcomes and daytime sleepiness; 2) to investigate if compliance, non-compliance, or the a...

This study evaluated a brief sleep intervention designed to improve the sleep, mood, and cognitive performance of professional electronic sports (esports) athletes from three major esports regions (i.e., Asia, North America, and Oceania). Fifty-six esports athletes from South Korea (N = 34), the United States (N = 7), and Australia (N = 15) complet...

The current Russian war against Ukraine is of global concern. It builds on the annexation of Crimea in 2014 and subsequently the war in the Donbas region of Ukraine, and has become a large-scale Russian invasion of Ukraine from three directions, Crimea in the south, Russia in the east, and Belarus in the north. Despite the geopolitical background t...

Background Adolescents with a late chronotype are at greater risk for mood disorders, risk-taking behaviors, school absenteeism, and lower academic achievement. As there are multiple causes for late chronotype, the field lacks studies on the relationship between mood, circadian phase, and phase angle of entrainment in late chronotype adolescents. T...

Study Objectives Recurrent nightmares in childhood may have a range of detrimental effects for both the child and parents. This randomized controlled trial evaluated the efficacy of a novel parent-based intervention for childhood nightmares, using a new device called the “Dream Changer.” Methods A total of 56 children aged 3–10 years (M = 7.1 ± 2....

Professional and colloquial sleep hygiene guidelines advise against evening physical activity, despite meta-analyses of laboratory studies concluding that evening exercise does not impair sleep. This study is the first to investigate the association between objectively measured evening physical activity and sleep within a real-world big-data sample...

Inadequate sleep and excessive exposure to media screens have both been linked to poorer mental health in youth. However, the ways in which these interact to predict behaviour problems have yet to be examined using objective sleep measurement. The lack of objective evidence for these relationships in young children has recently been defined by the...

Abstract Background. Growing evidence supports a link between late chronotype and increased risk for affective disorders. Yet, the tendency toward a late chronotype and the onset of mood disorders often emerge during adolescence. Few studies have examined the relationship among school-aged adolescence. Therefore, the present study aimed to investi...

Background With the outbreak of the COVID‐19 pandemic, pediatric experts called attention to the potential adverse effects of living restrictions (e.g., lockdown) on child well‐being, but at the same time– acknowledged their possible benefits. To date, only few data‐driven reports have been published on child sleep during COVID‐19, and all have bee...

Study Objectives. During adolescence, an interplay between biological and environmental factors leads to constrained sleep duration and timing. Given the importance of restorative sleep for cognitive, emotional, and physical health during this developmental period, the high prevalence of sleep deprivation is a public health concern. One of the prim...

Study objectives To investigate circadian typology in a large, representative sample of Norwegian adolescents, and its implications for sleep health. Methods The sample included 3920 1st year high school students aged 16–17 years. Respondents completed a web-based survey, including the short version of the Horne-Ostberg Morningness-Eveningness Que...

Circadian dysregulation and depressed mood commonly co-occur in young people, yet mechanisms linking Delayed Sleep-Wake Phase Disorder (DSWPD) with depression are poorly understood. This study aimed to examine the role of repetitive negative thinking (RNT), by comparing sleep, RNT and depressive symptomology between 40 good sleeping youth and 63 yo...

Objective The COVID-19 pandemic has profoundly impacted families, yet studies on its effects on infants and their parents have thus far been sparse and based mostly on retrospective parent reporting. This study aimed to prospectively evaluate the impact of COVID-19 living conditions on infant and parent sleep, as well as infant screen exposure, par...

Behavioural sleep interventions (e.g., extinction-based methods) are among the most efficacious evidence-based techniques in the treatment of infant sleep problems. However, behavioural sleep interventions can be challenging for families to successfully implement. This review aims to summarise current research surrounding the potential barriers tha...

Objective: This study aimed to investigate self-reported sleep duration, sleep quality and sleep problems in a Mexican adult population by considering age, sex, geographical regions and urban/rural residency. Design/Measurements: Cross-sectional national adult survey based on the 2016 Mexican National Halfway Health and Nutrition Survey data. Set...

Objective: This study aimed to provide the first estimate of sleep knowledge, practices, and attitudes regarding paediatric sleep in Australian health professionals. Methods: 263 Australian health professionals (medical practitioners, nurses, psychologists, social workers, occupational therapists, pharmacists, dentists and sleep coaches) completed...

Esports is becoming increasingly professionalized, yet research on performance management is remarkably lacking. The present study aimed to investigate the sleep and mood of professional esports athletes. Participants were 17 professional esports athletes from South Korea (N = 8), Australia (N = 4), and the United States (N = 5) who played first pe...

Background and Objective Although sleep is a potentially important determinant of performance in esports, there have been no published data on the sleep behavior of professional esports athletes. The aim of this study is to investigate sleep aspects and sleep risk factors in esports athletes. Methods Thirty-four esports athletes were compared with...

The aim of the present study was to describe sleep patterns in a large and representative sample of Norwegian adolescents. The sample included 4,010 first‐year high school students, aged 16–17 years (54% female), who completed a web‐based survey on sleep patterns. The process of going to sleep was addressed as a two‐step sequence of (a) shuteye lat...

Objectives This study longitudinally compared the sleep of infants in the United States whose mothers were in home confinement to those whose mothers were working as usual throughout the COVID-19 pandemic. Methods Mothers of 572 infants (46% girls) aged 1-12 months (M = 5.9, standard deviation = 2.9) participated. Assessments were conducted on 4 o...

Introduction Perfectionism is an often overlooked yet consistent construct related to insomnia in the scientific literature. Perfectionism and insomnia are both highly prevalent in adolescence. However, there is a dearth of research examining mechanisms linking perfectionism with insomnia, particularly in young people. The current study aimed to in...

Background Delayed sleep–wake phase disorder (DSWPD) during adolescence has been linked to impaired health and poor functioning. However there is a dearth of knowledge about DSWPD in young adulthood. We seek to contribute knowledge on the prevalence and correlates of DSWPD in this age group. Methods Data were drawn from a 2018 national survey of s...

‘Hippocrates flagged the value of sleep for good health’ was the first line of the Annual Research Review (ARR) by Gregory and Sadeh (2016) in this journal, titled Sleep problems in childhood psychiatric disorders – a review of the latest science. Where Hippocrates has been referred to as the ‘Father of Medicine’, Professor Avi Sadeh has been respe...

Study Objectives Evidence for the association between screen time and insufficient sleep is bourgeoning, and recent findings suggest that these associations may be more pronounced in younger compared to older children, and for portable compared to non-portable devices. However, these effects have yet to be investigated within the beginning of life....

Background: Co-occurring insomnia and symptoms of depression, anxiety and stress pose difficult diagnostic and treatment decisions for clinicians. Cognitive Behavioral Therapy for Insomnia (CBTi) is the recommended first-line insomnia treatment, however symptoms of depression, anxiety and stress may reduce the effectiveness of CBTi. We examined the...

Background Sleep problems are common in adolescence, and frequently comorbid with both anxiety and depression. Research studies have suggested a bidirectional relationship between sleep and psychopathology, which includes evidence that sleep interventions can alleviate symptoms of anxiety and depression. However, little is known about the nature of...

Introduction Esports is becoming increasingly professionalized, yet research on performance management is remarkably lacking. The present study aimed to investigate sleep and mood in professional esports athletes. Methods Participants were 17 professional esports athletes from South Korea (8), Australia (4) and the US (5) who played First Person S...

Objective The present study investigated the relationship between difficulty initiating sleep and depressed mood and whether it is mediated by repetitive negative thinking. A moderating role of perfectionism was also examined. Methods We surveyed 393 adolescents aged 14 to 20 years (M = 17.32, SD = 1.90) via an online questionnaire that assessed d...

Esports is a booming global industry and has been officially included in the lead-up to the 2020 Olympics in Tokyo. Given that esports is a cognitive based activity, and sleep is well known to be critical for optimal cognitive functioning, our research group recently proposed that sleep might be an important determinant of esports performance. The...

Growing evidence shows a link between mood and chronotype. The majority of studies measure chronotype as a preference for morning/evening activities, rather than actual sleep behavior (i.e., midsleep) or biological markers of sleep timing (e.g., dim light melatonin onset). Most studies show an association between chronotype and mood and identify ev...

Background: Development induces changes in sleep, and its duration has been reported to change as a function of aging. Additionally, sleep timing is a marker of pubertal maturation, where during adolescence, the circadian rhythm shifts later. Typically, this is manifested in a later sleep onset in the evening and later awakening in the morning. Th...

Insomnia is one of the most prevalent sleep disorders in school-aged children and adolescents. Although cognitive behavioral therapy for insomnia (CBT-i) is the first-line treatment for adults, and existing studies show promising effects also for children and adolescents, the number of randomized controlled trials in younger age groups is rather sm...

Objectives: Recent evidence indicates that adolescents' motivation to change sleep-wake patterns is low, despite significant impact of adolescent sleep problems on many areas of daytime functioning. The aim of the present study is to evaluate components of adolescents' motivation, and subsequent changes in behaviour. Methods: Fifty-six adolescen...

Objective: To determine whether the main reason for bedtime is associated with sleep and adaptive functioning in adolescents. Methods: Participants were 1374 adolescents (X age = 16.8 years, SD = 0.58; 33.6% male) from Helsinki, Finland. Adolescents completed a questionnaire battery including the Munich Chronotype Questionnaire, Strengths and Di...

Objective: To systematically investigate whether cognitive “insomnia” processes are implicated in adolescent Delayed Sleep–Wake Phase Disorder (DSWPD) and to examine whether these processes are responsive to chronobiological treatment. Method: Sixty-three adolescents (M = 15.8 ± 2.2 years, 63.5% f) diagnosed with DSWPD and 40 good sleeping adolesce...

Introduction Fragmented REM sleep may impede overnight resolution of distress and increase depressive symptoms. Furthermore, both fragmented REM and depressive symptoms may share a common genetic factor. We explored the associations between REM sleep fragmentation, depressive symptoms, and a polygenic risk score (PRS) for depression among adolescen...

Study Objectives Provide actigraphic reference values for motor activity during sleep for children and adolescents ages 8–17 years. Methods Participants were 671 healthy community-dwelling children and adolescents (52% female, mean age 13.5+2.4 years) from the United States (64%) and Australia (36%). All participants wore an Ambulatory-Monitoring...

Difficult early morning awakening is one of the defining symptoms of delayed sleep–wake phase disorder. It is accompanied by low cognitive arousal and drowsiness resulting in difficulty concentrating and focusing attention upon awakening. We designed the current study to quantitate cognitive performance (i.e. omissions, commissions, reaction time [...

Shuteye latency (SEL) refers to the time spent performing activities in bed before attempting sleep. This study investigates (a) the prevalence, duration and predictors of SEL, (b) its association with insomnia symptoms (sleep onset latency [SOL], sleep quality and fatigue), and (c) the activities engaged in during SEL. A representative sample of 5...

Highlights. •Adolescents typically restrict their sleep, and this may impact on sleep spindle activity. •Experimental sleep restriction leads to changes in sleep architecture and spindle activity. •Fast spindle amplitude decreases and fast duration increases during severe sleep restriction. Abstract. Background. The tendency for adolescents to hav...

Higher sleep spindle activity generally relates to better cognitive performance in adults, while studies in children often show the opposite. As children become young adults, there is rapid brain maturation and development of higher-order cognitive functions, and therefore investigations within this age group may elucidate the relationship between...

Evidence of night‐to‐night variation in adolescent sleep spindle characteristics is lacking. Twelve adolescents (M = 15.8 ± 0.8 years, eight males) participated in a laboratory study involving 9 nights with 10 hr sleep opportunity. Sleep electroencephalograph was analysed and intra‐class coefficients calculated to determine the reliability of sleep...

The present study aimed to investigate whether Australian adolescents with Delayed Sleep-Wake Phase Disorder have impaired cognitive performance and whether chronobiological treatment for Delayed Sleep-Wake Phase Disorder improves adolescents' sleep, daytime functioning and cognitive performance. Adolescents with Delayed Sleep-Wake Phase Disorder (...

Study Objectives To examine the relationship between pre-sleep cognitions and sleep-onset difficulties in an adolescent sample. Methods Participants were 385 students (59% male) from grades 9 to 11, between 13 and 18 yrs old (M=15.6, SD=1.0), from 8 co-educational high schools of varied socio-economic status in metropolitan Adelaide, South Austral...

Study objectives: To evaluate the efficacy of bedtime fading to reduce sleep disturbances in preschool aged children by using a group parent education format. Design: A repeated-measures design (pretreatment, treatment, post-treatment and two year follow-up). Setting: Flinders University Child and Adolescent Sleep Clinic, Adelaide, South Austr...

Difficulties falling asleep are common among adolescents, especially during times of stress. Adolescents may thus benefit from brief techniques (15 min) that decrease pre-sleep cognitive-emotional arousal and sleep-onset latency. The present study used a 3 (intervention: mindfulness bodyscan mp3, constructive worry, control) by 3 (time: baseline, w...

A randomised controlled trial evaluated bright light therapy and morning activity for the treatment of Delayed Sleep-Wake Phase Disorder (DSWPD) in young people. 60 adolescents and young adults (range= 13-24 years, mean= 15.9±2.2 y, 63% f) diagnosed with DSWPD were randomised to receive three weeks of post-awakening Green Bright Light Therapy (∼507...