A recent study attempted to determine whether children’s differences in adjustment might be associated with differences in sleep.
Researchers John E. Bates, Richard J. Viken and Douglas B. Alexander, Indiana University; Jennifer Beyers, University of Washington; and Lesley Stockton, University of Indianapolis, had observed in their work with families of young children with behavior problems that many of these children appeared to get inadequate sleep.
Previous research studies also found small but significant relations between low amounts of sleep and higher levels of aggressive and disruptive behaviors and
greater likelihood of psychiatric diagnoses. Many parents report sleep-deprivation “meltdowns.” Links were not found between sleep and internalizing adjustment problems such as anxiety and depression.
Head Start children
In the current study, Bates et al. studied predominantly low-income families whose children were enrolled in Head Start preschools. A university daycare center provided a comparison group. Their goal was to determine if ordinary variations in preschool children’s sleep was related to their adjustment to preschool and to differences in family functioning.
Most young children sleep nearly half of each day, but there are considerable differences between individuals. These differences appear to be related to genetic inheritance as well as environmental and developmental factors. Many children, especially young ones, have sleep problems such as bedtime resistance, delays in falling asleep, night waking and sleepwalking.
Forty-two percent of one-to-three-year-olds show problematic bedtime resistance, and 35 percent wake and demand attention at night. Bedtime struggles become increasing common from the second to the fifth year and are still common in 25 percent of children aged 5 to 12.
Sleep deprivation and relationships
Sleep loss appears to be a form of stress that creates greater emotional ups and downs and difficulties in attention management. Higher-order cognitive abilities, such as those needed to learn abstract concepts, have been shown to be impaired by sleep loss. A sleep-deprived child who is alone watching television is less likely to have difficulties than one who is playing in a more exciting and complex social situation such as a preschool classroom.
Sleep problems also appear to be incompatible with a comfortable family routine. Children with sleep disturbances had poorer relations with their parents and had parents with more strained relationships. Research reviewed by Bates et al. also shows that children’s sleep patterns are associated with adjustment problems and that these same sleep problems may be associated with family functioning and parenting. It remains possible, however, that sleep problems are linked to adjustment mainly as a by-product of family stress and parenting deficiencies. Contrarily, there is some research on treatment of sleep problems indicating that improving sleep patterns can result in substantial reductions of behavior problems.
Because it seems possible that daily variations in the sleep schedule might create stresses similar to jet lag, the current study considered not only the amount but the variability of sleep. These researchers considered how differences in daily patterns of sleep are related to the adjustment of children. They studied sleep variations in relation to family functioning and level of stress and measured the child’s adjustment in both the home and preschool settings. The goal of this study was to see whether sleep variations accounted for differences in adjustment, even after taking into account family factors traditionally associated with children’s behavior differences.
Data on life events
Data was collected from four groups of preschool children — three Head Start classes and one university daycare class. The Head Start families were more likely to have a single mother with less education and lower occupational standing than the university families. Information about children and families was collected from mothers through an initial two-hour interview, a one-hour follow-up interview and their daily logs of children’s sleep behavior. Teachers provided information through initial and follow-up questionnaires and daily behavior ratings.
Mothers were carefully trained to keep sleep logs. They recorded the times their children went to sleep and when they woke up each day. Sleep disruption was measured as the variability in the amount of sleep per night, the average amount of sleep across four weeks, and the average bedtime. Both nighttime sleep and total sleep (which included naps) were calculated.
Interviewers rated mothers on the quality of their data collection. Child-rearing practices and the climate in the family was measured with the Family Environmental Scale as well as through direct observation of mother-and-child interactions. In addition, each mother was asked to imagine her child acting aggressive or unfriendly in five different hypothetical situations and to describe how they would respond.
Each mother rated how hard 26 life events were for her child. Teachers’ ratings of behavior were collected using the Preschool Adjustment Questionnaire and the Preschool Behavior Questionnaire. In addition, the teachers completed daily reports on eight positive and four negative behaviors.
Impact on pre-school adjustment
Two interviewers independently rated mothers’ ability to keep accurate sleep records. Only participants who had complete data and whose sleep records were judged to be of medium or high quality were included in the study. Overall, the children were described by their mothers as getting, on average, only 10.63 hours of sleep per day, less than the norm of 12 hours of total sleep at age four and 11 hours at age five. Study children also went to bed at 9:30 p.m., one hour later than the average bedtime reported in 1987.
There was a consistent pattern of modest but statistically significant correlations between a child’s variability in amount of sleep and his or her preschool adjustment and family stress indexes. The same pattern held for a child’s bedtime variability. Lateness of bedtime or amount of sleep did not appear to be related to a child’s adjustment or family stress. These results suggest that children who are on a more regular sleep schedule are likely to adjust and behave better in preschool.
The importance of the quality of the mothers’ observations was demonstrated in comparisons between data from the whole sample versus only the high-quality data. Families that impressed interviewers as most conscientiously recording the sleep data provided the strongest evidence of a link between child sleep regularity and positive adjustment in school.
The irregularity of sleep exhibited by some children showed a tendency to predict behavior problems. This research demonstrates that children’s disrupted sleep patterns were associated with relatively poor adjustment in preschool, even after considering family stress and management practices. As expected, positive parenting practices predicted a child’s positive adjustment to school, and more highly stressed families tended to have less positive parenting practices.
Regularity of sleep more important than amount
This study demonstrates that children whose mothers reported variable sleep schedules had more negative adjustments to preschool. These results emphasize the importance of regularity of sleep rather than the total amount of sleep. Sleep irregularity accounted for variation in preschool adjustment independent of variation in family stress and management.
Bates et al. contend that children who are chronically variable in their sleep schedule may experience states similar to jet lag — fatigue and cognitive disorientation. Some children are probably less affected in their daily functioning by disrupted sleep rhythms than others. The average child, however, appears to be negatively affected. Fatigue from interrupted sleep interferes with attention focus and performance. Bates et al. speculate that sleep disruptions make it difficult for children to regulate their behavior.
Limitations of this study include that it was descriptive rather than experimental, that the measurements were not ideal, and that it focused on low-income, mostly European-American families and thus can not be applied to other populations. More extensive and precisely recorded direct observations would provide more accurate data.
In conclusion, previous research supports the assumption that sleep differences are associated with the behavioral adjustment of children. This study’s findings indicate that irregular sleep patterns affect children’s functioning in preschool, even when family functioning is taken into account.
“Sleep and Adjustment in Preschool Children: Sleep Diary Reports by Mothers Relate to Behavior Reports by Teachers” Child Development Volume 73, Number 1, February 2002 Pp. 62-74.
Published in ERN April 2002 Volume 15 Number 4