U. PITTSBURGH (US)—Infants with irregular patterns of sleeping, eating, and playing were significantly more likely to experience symptoms of anxiety more than a decade later.

“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,” says Timothy Monk, professor of psychiatry at the University of Pittsburgh.

It is well known that certain psychiatric symptoms, particularly related to depression and anxiety, are associated with dysfunction of the 24-hour biological clock, known as the circadian system.

In the new study, researchers 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.

Details appear in the current issue of Psychiatry Research.

To measure babies’ lifestyle routines and sleep regularity, 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.

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, the researchers say.

More confident and perceptive parenting, in turn, supports the development of an infant’s emotional regulatory capacities. A baby’s 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,” says Linnea Burk, clinical assistant professor at the University of Wisconsin and a co-author of the study..

“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.

“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,” notes 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.”

Researchers from the University of California, Berkeley, contributed to the study, which was funded in part by the National Institute of Mental Health, the National Institutes of Health and the John D. and Catherine T. MacArthur Foundation.

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