Sunday, July 22, 2007

Sleep pattern linked with teen's behavior: Scientific American

Sleep pattern linked with teen's behavior: Scientific American

NEW YORK (Reuters Health) - New study findings suggest that a preference for nighttime over daytime activities may be associated with antisocial behavior in adolescences, even in children as young as 8 years old.

Those who prefer later bedtimes appear to exhibit more antisocial behavior than those who like to wake early and participate in daytime recreational activities, researchers report.

"A preference for evening activities and staying up late is related to problem behavior and is evident even in preteens," study co-author Dr. Elizabeth J. Susman, of Pennsylvania State University, told Reuters Health.

[...]

Boys who experienced prolonged high levels of cortisol -- smaller decreases in cortisol levels from the time of awakening until 4 pm -- tended to have more behavior problems than did their peers, the report indicates. The association was not true for girls, however.

Normally, levels of cortisol, the stress hormone associated with circadian rhythms, peak in the morning upon awakening and plateau during the afternoon and evening hours.

Abnormalities in cortisol secretion, have also been associated with clinical depression and antisocial behavior in earlier studies, the researchers note.

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