It is well known that certain psychiatric symptoms, particularly related to depression and anxiety, are associated with dysfunction of the 24-hour biological clock, also known as the circadian system. In this study, the research teams followed 59 children for 13 years, starting at age 1 month, to determine if the regularity of their daily behaviors in infancy could predict depression and anxiety symptoms when the children were older.
“We found that a baby’s daily routine and sleep patterns at 1 month were predictive of the amount of anxiety shown more than 10 years later while the child was attending school, but we did not find a significant correlation with depression,” said Timothy H. Monk, Ph.D., D.Sc., lead co-author of the study, professor of psychiatry and director of the Human Chronobiology Research Program at the University of Pittsburgh School of Medicine.
To measure lifestyle routines and sleep regularity in babies, the researchers used a diary tool they created called the Baby Social Rhythm Metric (SRM), which parents used to document very young babies’ routines a week at a time. In 1990 and 1991, the Baby SRM diary was completed by 59 couples for two consecutive weeks when their infant was 1 month old. The diary tracked the baby’s sleep times, as well as feeding, playing, diaper changing and receiving comfort.
The researchers suggest that greater regularity in daily activities may increase the predictability of an infant’s demands, leading to enhanced parental perception of the baby’s cues and increased parental confidence in meeting the infant’s needs. They argue that more confident and perceptive parenting, in turn, supports the development of an infant’s emotional regulatory capacities. The ability to self-soothe and self-regulate are important emotional regulatory skills.
“Further, cognitive skills, such as directed-attention, or the ability to concentrate, also are likely involved in emotion regulation. These attention-directed processes may help to adjust emotional arousal and aid children in managing overt behavior when emotions are less well-regulated by other means,” noted Linnea R. Burk, Ph.D., clinical assistant professor at the University of Wisconsin and a co-author of the study. “Children with a well-developed ability to direct attention in a variety of situations likely use less cognitive effort, and therefore may have more cognitive resources available to aid in regulatory processes.”
The study supports the potential importance of the circadian system and its development in the life of the child, and possibly suggests a genetic basis that the researchers will explore in future work. “For many years, experts have believed that regularity in an individual’s daily lifestyle might be associated with better mental health,” noted Dr. Monk.
“By being able to follow these children from birth to the 9th grade, we can show that greater regularity, even in very early life, can be associated with less school-age anxiety later on.”
Other co-authors of the study include David J. Kupfer, M.D., University of Pittsburgh School of Medicine; Marjorie H. Klein, Ph.D., and Marilyn J. Essex, Ph.D., a lead co-author, University of Wisconsin-Madison; and Adriane M. Soehner, B.S., University of California, Berkeley.
This study was supported in part by funding provided by the National Institute of Mental Health, the National Institutes of Health and the John D. and Catherine T. MacArthur Foundation.
Megan Grote Quatrini