We know that marriage problems can have a negative effect on families, especially children. Now a new study of more than 350 families has found that marital instability when children are 9 months old may also affect youngsters' sleep, predicting sleep problems when children are 18 months old. Specifically, instability in the parents' relationship when the children are 9 months old predicted difficulties falling asleep and staying asleep when they were 18 months old.
The findings appear in the journal Child Development. The study was conducted by researchers at the Oregon Social Learning Center, University of Leicester, Cardiff University, University of Pittsburgh, University of California at Davis, The Pennsylvania State University, University of New Orleans, and Yale Child Study Center.
The researchers sought to assess the relationship between marital instability—for example, parents who were contemplating divorce—and children's sleep problems—namely, difficulties getting to sleep or staying asleep. Their inquiry was based, in part, on the possibility that changes in the brain systems involved in how children develop and regulate their sleep patterns reflect the impact of family stress on children.
They followed more than 350 families starting when their babies were 9 months old and continuing over a nine-month period. The researchers chose to study adoptive families to rule out the possibility that any ties between parents' behavior and children's sleep were due to shared genes; previous studies into this issue have looked at families who were biologically related.
The researchers found that marital instability when the children were 9 months old predicted increases in children's sleep problems when they were 18 months old. This finding held true even after taking into consideration such factors as children's difficult temperaments, parents' anxiety levels, and birth order. But the researchers also found that the inverse wasn't true—that is, children's sleep problems didn't predict marital instability.
"Our findings suggest that the effects of marital instability on children's sleep problems emerge earlier in development than has been demonstrated previously," according to Anne M. Mannering, who was a research associate at the Oregon Social Learning Center when she worked on the study; she is currently with Oregon State University. "Parents should be aware that marital stress may affect the well-being of their children even in the first year or two of life."
The study was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute on Drug Abuse, and the Office of the Director of the National Institutes of Health.