百分之三十的儿童在4岁内均有睡眠紊乱问题。睡眠紊乱最常发生在1～2岁的年龄组儿童。研究人员检查了308名有睡眠问题的婴儿,他们的母亲大多数是英国中产阶级的白人妇女。当婴儿在8个月和3岁时,通过询问这些妇女,了解婴儿的睡眠和行为问题,并了解妇女本人精神上的问题。一个婴儿被认为有睡眠问题,即在醒后一个多小时才能恢复睡眠,或一夜醒3次以上。研究人员发现18％的8个月婴儿均有睡眠问题。母亲的社会阶层、年龄、婴儿性别、出生时体重或上呼吸道感染次数似 Thirty percent of children have sleep disorders at age 4 years. Sleep disorders most often occur in children aged 1-2 years. Researchers examined 308 sleep-deprived infants, mostly mothers of white middle-class British women. When infants at 8 months and 3 years old, by asking these women, to understand the baby’s sleep and behavior problems, and to understand the woman’s own mental problems. A baby is considered to have a sleep problem, that is, more than an hour after waking to resume sleep or wake up more than 3 times a night. Researchers found that 18% of 8-month infants had sleep problems. Mother’s social class, age, baby’s sex, weight at birth, or number of upper respiratory tract infections