Do toddler language skills predict ADHD later?

Children in low-income families hear about 20 million fewer words by age 3 than children in more affluent families. "Children who lack strong language skills are less able to regulate their behavior and ultimately more likely to develop behavior problems," says Issac Petersen. (Credit: Sarah Ross/Flickr)

Children who have poor language skills during their toddler years may also be unable to control their behavior—which can lead to ADHD and other disorders of inattention and hyperactivity.

“Young children use language in the form of private or self-directed speech as a tool that helps them control their behavior and guide their actions, especially in difficult situations,” says Isaac Petersen of the clinical science program in the psychological and brain sciences department at Indiana University.


“Children who lack strong language skills, by contrast, are less able to regulate their behavior and ultimately more likely to develop behavior problems.”

Early childhood development has increasingly become a focus for public policy—in debates over universal preschool, recognition of a “word gap” between rich and poor children, and new pediatric recommendations on reading to infants.

“Children’s brains are most malleable earlier on, especially for language,” says John Bates, professor in the psychological and brain sciences department and coauthor of the study.

“Children are most likely to acquire skills in language and self-regulation early on. Many of the states are starting to focus on preschool, edging toward universal preschool. But early development specialists are not necessarily available. I would have programs more readily available to families—and focused on children most at risk as early as possible.”

Self-regulation is key

Many previous studies have shown a correlation between behavior problems and language skill. Children with behavior problems, particularly those with attention deficits and hyperactivity, such as in ADHD, often have poor language skills.

Whether one of these problems precedes the other and directly causes it was until recently an open question. But in a longitudinal study published last year, researchers concluded that the arrow points decisively from poor language ability to later behavioral problems, rather than the reverse.

The current study, published in the journal Development and Psychology, shows that it does this by way of self-regulation, a varied concept that includes physical, emotional, cognitive, and behavioral control.

Self-regulation is integral to children’s capacity to adapt to social situations and to direct their actions toward future goals. The absence of self-regulation abilities is a key predictor and component of future behavior problems.

A number of studies have sought to explain the role of language in the development of self-regulation in terms of the cognitive and neurological mechanisms by which they are linked. This study traces the way they unfold over time and the role of self-regulation in this process.

To do this, the researchers followed a group of 120 toddlers for a year, beginning when they were age two and a half and following up when they were 36 months and 42 months old. At each of these points they tested the children’s language skills and behavioral self-regulation, using tests for verbal comprehension and spoken vocabulary, as well as three tasks measuring self-regulating abilities.

They also used parent and secondary caregiver assessments of behavioral problems. The findings suggest that language skill predicted growth in self-regulation, and self-regulation, in turn, predicted behavioral adjustment.

20 million more words

The study lends renewed force to the argument that early childhood may offer a pathway for reducing social inequality. For what makes the “developmental cascade” from language to behavior particularly troubling, the researchers point out, is that children most at risk for a deficit in language ability, those from lower-income households, are often the least likely to get the services needed to remedy the problem.

Studies, for example, have shown a “word gap” between children of low income and those in affluent families, who hear 20 million more words by age three than their low-income counterparts. This gap results in less developed verbal and reading skills. If, as this study suggests, poor language skills lead to problems with self-regulation and behavior, this can in turn contribute to the less easily reversible and more costly social or academic problems in adolescence and later, adulthood.

“Don’t expect all children to be at the same level early on. If their language is slow to develop and self-regulation is lacking, they are likely to catch up with proper supports,” Petersen says.

“Among those who are slow, some could develop problems. If, by the age of three and a half, a child is still lagging, it may be worth pursuing treatment for language and self-regulation skills—the earlier the better.”

Angela Staples, research assistant professor at University of Virginia, is a coauthor of the study. The National Institute of Mental Health and the Eunice Kennedy Shriver National Institute of Child Health and Human Development supported the research.

Source: Indiana University