Genetics wakes up for human sleep

Sleep patterns and problems among chinese adolescents

OBJECTIVES

Little is known about sleep patterns and problems in Chinese adolescents. This study was designed to examine sleep/wake patterns and problems and their associations with parent sleep among adolescents in China.

METHODS

This report represents part of an epidemiological study of sleep and health in 6 high schools in Jinan city, China. A total of 1056 adolescents and 838 parents completed a questionnaire in March or April 2005. Participants consisted of 625 boys and 441 girls, 557 seventh-graders (mean age: 13.5 +/- 0.6 years) and 509 tenth-graders (mean age: 16.4 +/- 0.7 years), and 603 mothers and 235 fathers. Adolescents and parents reported their own sleep/wake patterns and problems.

RESULTS

Average morning rising time (5:56 am vs 8:13 am) and sleep duration (7.5 hours vs 9.4 hours) differed significantly between weekdays and weekends. Compared with seventh-graders, 10th-graders went to bed later and awoke earlier, resulting in approximately 1 hour of sleep less. Of the adolescents, 18.8% reported their sleep quality as poor, 26.2% were not satisfied with their sleep, 16.1% had insomnia, and 17.9% had daytime sleepiness. Significant but low adolescent-parent correlations were observed for sleep/wake patterns and perceived sleep quality. Difficulty initiating sleep in adolescents was significantly associated with history of insomnia in mothers and fathers.

CONCLUSIONS

Sleep insufficiency, insomnia, and daytime sleepiness are prevalent in Chinese adolescents. Sleep insufficiency on weekdays may be attributable to earlier morning rising to meet school schedules. Parental history of insomnia is associated with elevated risk for insomnia symptoms in adolescent offspring, although adolescent-parent correlations in sleep/wake patterns are relatively low.

Sleep and COMT polymorphism in ADHD children: preliminary actigraphic data

OBJECTIVE

To examine whether COMT (catechol-O-methyltransferase) polymorphism modulates aspects of sleep in children diagnosed with attention-deficit/hyperactivity disorder (ADHD).

METHOD

Nightly sleep actigraphic recordings during a double-blind, placebo-controlled, crossover clinical study (1 week of 0.5 mg/kg MPH; 1 week of placebo) were obtained for 34 children, 7.4 to 12 years old, diagnosed with ADHD (DSM-IV). Diagnosis was generated by the Diagnostic Interview Schedule for Children and was confirmed by multidisciplinary consensus.

RESULTS

Children who were Val allele carriers had poorer sleep continuity compared with children with the Met-Met genotype while receiving a placebo and while receiving methylphenidate.

CONCLUSIONS

The findings of the present study support the hypothesis that sleep disturbances in children with ADHD are related to the underlying pathophysiology of the disorder.