Actigraphy An Actigraph (Micro-mini-Motion logger, Ambulatory Monitoring Inc., Ardsley, New York , USA) is a wrist-watch sized motion detector that has been shown to be highly valid and reliable for differentiating sleep from wakefulness, as well as recording total sleep time (r=97 compared to polysomnography). Participants will wear an actigraph for 5 consecutive nights on their nondominant wrist. Sleep patterns will be estimated using the validated Sadeh scoring algorithm developed for adolescents. Actigraph sleep measures included: (a) sleep onset/ bedtime; (b) sleep offset/wake time, (c) time in bed (minutes from sleep onset to sleep offset), (d) actual sleep time (number of sleep minutes between sleep onset and sleep offset), (e) sleep efficiency (actual sleep time divided by time in bed, expressed as a percent), (f) longest sleep period (longest consecutive period scored as sleep without any identified awakening), (g) median number of nighttime wakings (at least 5 consecutive minutes), and (h) median length of nighttime waking.