Sleep, behavioral problems often linked in teens: study found increased cortisol near sleep onset and REM density were predictive of future depression.
This key phase of development has broad relevance to adolescent behavioral and emotional health, and should be viewed as a time of opportunity for early intervention.
Dr. Dahl and his colleagues at Western Psychiatric Institute and Clinic in Pittsburgh carried out a series of studies in children and adolescents, aged 8-16, with affective disorders that included several measures of sleep and hypothalamic-pituitary-adrenal (HPA) axis regulation.
The subjects included 128 children studied during an episode of depression, 102 children with anxiety disorders, and 102 age-matched controls who were medically and psychiatrically healthy and had negative family histories for depression.
Despite extensive subjective sleep complaints in depressed children and adolescents, younger prepubertal adolescents showed little or no objective evidence of sleep and cortisol dysregulation.
But midpubertal and older adolescents with major depressive disorder revealed evidence of EEG sleep and cortisol changes associated with adult depression, including increased sleep latency, decreased REM-latency, increased REM-density, and cortisol and growth hormone changes near sleep onset.
Increased cortisol near sleep onset and REM density were predictive of future episodes of depression, said Dr. Dahl, also the Staunton Professor of Psychiatry and Pediatrics at the University of Pittsburgh.
In contrast, children with anxiety disorders showed evidence of earlier EEG sleep and cortisol changes. The anxiety group took significantly longer to fall asleep, had less total sleep time, less slow-wave sleep, and higher levels of cortisol at bedtime, compared with the healthy controls and with children with depression.
Some changes in sleep regulation are biologic and linked to puberty; others are linked to social habits and environmental influences. Puberty is marked by increased daytime sleepiness, while changes in biologic timing systems related to the circadian system push adolescents toward more owl-like tendencies to stay up late and sleep in late.
At the same time, an increasing number of adolescents have access to stimulating activities in their bedrooms, such as MP3 players, electronic or video games, and cell phones. In addition, more are drinking caffeinated beverages. "Spiraling interactions between these domains can lead to vulnerability and spiral into serious clinical problems," Dr. Dahl said at the meeting, sponsored by the University of Pittsburgh and the American Neuroendocrine Society.
According to a National Science Foundation national sleep poll, 45% of adolescents and 62% of 9th-12th grade adolescents get an insufficient amount of sleep on school nights, averaging about 6.9 hours in the 12th grade. More than 10% of U.S. high school seniors must get up before 5:30 a.m. to catch buses.
Sleepiness and tiredness are well-known consequences of this school-sleep squeeze, he said. But sleep-deprived adolescents also suffer irritability, emotional lability, difficulties with affect regulation and cognitive-emotional integration, and deleterious direct effects on learning and memory consolidation.
A recently published study in incarcerated male juvenile and young offenders found that aggression was related to both quantity and quality of sleep (J. Adolesc. Health 2006;38:649-55).
Preliminary data from a second study indicate that inadequate sleep in substance-abusing adolescents may contribute to their experiencing aggressive thoughts and actions (Sleep 2006;29:512-20). Dr. Dahl called these results provocative not only because of the correlation between sleep and aggression but also because the study demonstrated that a 6-week integrative behavioral sleep intervention could decrease the frequency of reported aggressive thoughts and actions.
Such research raises compelling questions about specific mechanisms of sleep and affective changes, with the long-term goal of informing early intervention in high-risk populations at key points in development, Dr. Dahl said.
BY PATRICE WENDLING
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|Title Annotation:||Child/Adolescent Psychiatry|
|Publication:||Clinical Psychiatry News|
|Date:||Oct 1, 2006|
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