SECTION 6 - PEDIATRICS

Adolescent Sleep

Background

Sleep and the unique features of physical, cognitive, and social-emotional development that take place in adolescence must be considered separately and in relationship to sleep in children and in adults. Not only do the biological changes associated with puberty profoundly affect sleep and wakefulness, but many environmental and social factors are also implicated. Several sleep disorders are particularly prevalent (delayed sleep phase syndrome) or emergent (narcolepsy) in adolescence. Finally, the public health consequences of inadequate sleep (academic failure, drowsy driving) and the potential for primary and secondary prevention in this age group are important.

Progress In The Last 5 Years

- Studies of normal sleep and sleep patterns in adolescents have identified important issues regarding the basic developmental physiology of sleep and circadian rhythms in adolescence. The role of pubertal/hormonal influences on circadian sleep-wake cycles and melatonin secretion has been recognized, and the effects include development of a relative phase delay (later sleep onset and wake times) in early puberty and the development of a physiologically based decrease in daytime alertness levels in mid- to late- puberty. The genotypic expression in adolescence of delayed circadian phase preference has also been explored as an important factor determining the timing of sleep/wake cycles.

- Studies of homeostatic regulation of sleep and wakefulness have demonstrated that sleep needs in adolescence do not decline significantly, and that optimal sleep amounts remain about 9 hours into late adolescence. However, epidemiological research on "normal" sleep patterns and amounts suggests that adolescents only average 7 to 7 1/2 hours of sleep per night, resulting in the accumulation of a considerable sleep debt over time. These data suggest that chronic partial sleep deprivation is a serious problem in this age group and that particular subgroups may be at relatively higher risk.

- Environmental and social factors also impact significantly upon delayed sleep onset in adolescents. For example, many adolescents have highly irregular sleep/wake patterns from weekday to weekend. Another important factor potentially contributing to insufficient sleep is the early start time of many middle and high schools in the United States.

- Chronic sleep restriction in adolescents leads to significant neurobehavioral consequences related to decline in alertness levels. These include a negative impact on mood, vigilance and reaction time, attention, memory, behavioral control and motivation. These impairments may in turn be associated with significant declines in school and work/occupational performance, increased risk-taking behaviors (use of alcohol, illicit drugs, nicotine, caffeine, stimulants), and injuries. Adolescent males, for example, are one of the highest risk groups for fall-asleep motor vehicle crashes.

Research Recommendations

- Ascertain the impact of chronic partial sleep deprivation on health outcomes, including susceptibility to infection, metabolic consequences, immune function, and use of potentially harmful alertness-promoting agents such as caffeine and stimulant medications. Delineate the effects of chronic partial sleep deprivation and sleepiness in adolescents on higher level cognitive or '"executive" functions, such as verbal creativity, and working memory, on motivation, and on affect regulation. The assessment of health outcomes should also include occupational and sports injuries, and motor vehicle crashes, and should determine scope of the problem, high risk groups, and interactions with other high-risk behaviors and substances (alcohol, marijuana, etc.).

- Define the specific neurophysiologic mechanisms involved in the relationship between sleep and circadian timing and puberty.

- Determine the extent, patterns, and psychosocial factors responsible for chronic sleep restriction in adolescence. These studies should include cross-cultural analyses and should also include special and high-risk populations such as adolescents with co-morbid psychiatric conditions, mood disorders, attention deficit hyperactivity disorder (ADHD), and chronic illness.

- Determine the impact of interventions to address chronic sleep restriction in adolescents, including later school start times and high school sleep education programs.

- Determine the biopsychosocial and genetic factors that result in delayed sleep phase syndrome in adolescents, and assess the safety and efficacy of various treatment modalities, including administration of exogenous melatonin, chronotherapy, and bright light therapy.