Behavioral Regularity in Infancy Predicts Lower Anxiety Years Later

Lack of regularity in sleeping, eating, and play routines in infancy appears to be associated with risk for anxiety in childhood.

Infants with irregular patterns of sleeping, eating, and playing were significantly more likely to experience symptoms of anxiety more than a decade later, according to a prospective study of 59 children followed for 13 years beginning at age 1 month. The report was published online in the July Psychiatry Research.

“The study indicates there are long-term implications for early behavioral regularity,” co-author Linnea Burk, Ph.D., of the Wisconsin Psychiatric Institute and Clinics, told Psychiatric News. “Clinicians have long advocated for predictable care and sleep schedules for children, and this study provides clear support that these steps are not only important in the short run, while the children are young, but also to long-term outcomes in adolescence.”

Beginning in 1990 and 1991 as part of the Wisconsin Study of Families and Work, parents of 59 infants completed a diary tool called the Baby Social Rhythm Metric (Baby SRM), devised by the researchers to document lifestyle routines and sleep patterns a week at a time. The diary was a structured instrument that required parents to write down the starting time for each of four other major daily events in the infant's life—feeding, playing, diaper changing, and receiving comfort. There were 30 baby girls and 29 baby boys.

(The Wisconsin Study of Families and Work is a much larger prospective study of child development that has yielded a number of published papers. Information about the study is posted at <www.wsfw.us>.)

Follow-up information was collected on “sociability” at ages 4 months and 12 months as measured by the Infant Behavior Questionnaire, and on symptoms of depression and anxiety in children up to age 13. A measure of children's “directed attention”—reflecting the ability to focus attention on specific tasks and environmental exploration—was obtained from videotaped observations of a two-hour home visit when children were 4.5 years of age.

Separately, and only after follow-up data were gathered, an algorithm was developed that cast the four specified events measured in the Baby SRM into 12 two-hour segments covering the 24-hour day. The resulting metric related to how spread out around the clock the events were (reflecting a low SRM score and a high degree of irregularity) or the extent to which particular times of day predominated for each of the events (reflecting a high SRM score and a high degree of regularity).

The Baby SRM score ranged from 0 (least regular) to 7 (most regular).

The researchers found that a higher SRM score was associated with lower overall levels of anxiety symptoms in childhood. There was no significant correlation of Baby SRM with childhood depression.

Timothy Monk, Ph.D., a professor of psychiatry and director of the human chronobiology research program at the University of Pittsburgh, noted that an extensive body of research in adults has shown circadian rhythm is associated with mental health.

“These new findings in infants reinforce this view,” he said. “In terms of treating patients both young and old, it is worth encouraging patients to adopt, to the extent that they can, a highly regular daily life style with predictable timing of bedtime, rise time, meals, and work.”

Moreover, sociability and directed attention were both correlated with Baby SRM scores and with school-age anxiety and may serve as mediating factors.

“Greater regularity to daily activities may increase the predictability of infant demands, leading to enhanced parental perception of need cues and increased parental confidence, which further strengthens caretaking routines,” the researchers stated. “Thus, greater regularity in daily activities may enhance early parent–infant relationships, improve infant regulatory capacity, and promote environmental exploration as internal resources are available.”

This study was supported in part by funding from the National Institute of Mental Health, the National Institutes of Health, and the John D. and Catherine T. MacArthur Foundation.

Child psychiatrist and APA Treasurer David Fassler, M.D., said the results of the study are consistent with previous reports and with general clinical experience. “We're well aware that young infants display a range of distinct temperaments,” he said. “We also know that many of these early characteristics persist throughout childhood and into adulthood. The present study demonstrates that anxiety in childhood correlates with specific behavior patterns observed during infancy.

“The behavior of infants clearly affects and alters the nature of their interaction with their parents and other caregivers, which could easily influence emotional development from an early age,” Fassler said. “We also know that the expression of anxiety has a significant genetic component, elements of which could conceivably influence behavioral regularity during infancy.”

“Behavioral Circadian Regularity at Age 1 Month Predicts Anxiety Levels During School-Age Years” is posted at <www.sciencedirect.com/science/journal/01651781>.