OBJECTIVETo investigate the effects of sleep deprivation on intelligence development in primary school students.

METHODSBetween June 2009 and April 2010, 316 grade 5 students aged 10-11 years were selected from four primary schools in four administrative districts of Changsha, China by stratified random sampling. The intelligence characteristics of children with varying degrees of sleep deprivation were investigated using the Chinese Wechsler Intelligence Scale for Children.

RESULTSA total of 286 valid questionnaires were received, with a response rate of 90.5%. The survey was comprised of a sleep deprivation group (sleep time <8 hours per night; n=180) and a control group (sleep time ≥8 hours per night; n=106). The sleep deprivation group had significantly lower subtest scores, verbal intelligence quotient (IQ) (VIQ), performance IQ (PIQ) and full scale IQ (P<0.05) and significantly lower verbal comprehension factor score and memory/attention factor score compared with the control group (P<0.05). Compared with the control group, the moderate sleep deprivation subgroup had significantly decreased VIQ and full scale IQ as well as verbal comprehension factor score and memory/attention factor score (P<0.05), and the severe sleep deprivation subgroup showed decreases in all scores (P<0.05). The sleep deprivation group and moderate and severe sleep deprivation subgroups had significantly higher proportions of children with VIQ-PIQ imbalance than the control group.

CONCLUSIONSSleep deprivation adversely affects intelligence development, especially VIQ, in primary school students, and the adverse effects of sleep deprivation are mainly seen in students with moderate and severe sleep deprivation.