Child's Self-Control Reflected in Adult Health, Wealth, and Crime

Children who scored lower on measures of self-control as young as at age 3 were more likely to have health problems, substance dependence, financial troubles, and a criminal record by the time they reached age 32.

That was the finding from a longitudinal study of more than 1,000 New Zealand children who were followed for more than 30 years. The study was published online January 24 in the Proceedings of the National Academy of Sciences.

The study measured childhood self-control using parent and teacher assessments and included a gradient from low self-control to high self-control.

"Self-control is a vital skill for scanning the horizon to be prepared for what might happen to you, for envisaging your own future possibilities, for planning ahead to get where you want to go, for controlling your temper when life frustrates you, for getting along with other people and attracting their help and support, and for waiting for the really good things that are worth waiting for, instead of jumping for short-term enticements," study author Avshalom Caspi, Ph.D., told Psychiatric News. "We all use it every day, but some of us use it more skillfully than others.

"We think the most novel information from our study is the self-control gradient," Caspi said. "A gradient means that the situation is not a few problem kids who should be targeted for treatment; instead it means all of us could benefit from improving our self-control."

Study participants were members of the Dunedin Multidisciplinary Health and Development Study. The longitudinal cohort consisted of all individuals who were born between April 1972 and March 1973 in Dunedin, New Zealand, and who lived in the surrounding province and participated in the first follow-up assessment at age 3.

Assessments were carried out at ages 3, 5, 7, 9, 11, 13, 15, 18, 21, 26, and most recently 32, when 96 percent of the 1,015 study members still alive were assessed.

Children's self-control during their first decade of life was measured using observational ratings of children's lack of control at ages 3 and 5; and parent-, teacher-, and self-reports of the following factors at ages 5, 7, 9, and 11: impulsive aggression, hyperactivity, lack of persistence, inattention, and impulsivity.

The study found that children scoring lowest on those measures scored highest across a range of negative adult outcomes. These included health measures such as gum disease, sexually transmitted disease, obesity, and high cholesterol and blood pressure.

The same children were also more likely to be single parents, have a criminal conviction record, and be dependent on alcohol, tobacco, cannabis, and harder drugs.

To further corroborate the importance of self-control, Caspi and colleagues ran the same analysis on a sample of 500 pairs of fraternal twins in Great Britain and found that the sibling with lower self-control scores at age 5 was more likely than the other sibling to begin smoking, perform poorly in school, and engage in antisocial behaviors by age 12.

"This shows that self-control is important by itself, apart from all other factors that siblings share, such as their parents and home life," Caspi said.

"In our study, health, wealth, and crime outcomes followed a gradient across the full distribution of self-control in the population," Caspi told Psychiatric News. "If that gradient is correct, it would imply room for better outcomes even among the segment of the population whose childhood self-control skills were above average. Universal interventions that benefit everyone avoid singling out and stigmatizing anyone, and because of this, they often attract widespread citizen support. The gradient needs to be tested in population-representative samples from other countries beyond New Zealand."

Psychiatrist Sheppard Kellam, M.D., a long-time prevention researcher who reviewed the report, said it "enriches an existing literature on early interventions that have been tested systematically with long-term follow-up."

He is professor emeritus of psychiatry and past chair of the Department of Mental Health at the Johns Hopkins University Bloomberg School of Public Health.

Kellam was an editor of and contributing author to a supplemental issue of the journal Drug and Alcohol Dependence, published by the National Institute on Drug Abuse in 2008, describing longitudinal epidemiologic studies of the impact of one universal, school-based intervention, known as the Good Behavior Game, on a range of adult behavioral and social outcomes. Those outcomes included substance abuse and dependence disorders, smoking, and antisocial personality disorder (Psychiatric News, January 1, 2010).

The game is directed at socializing children to the role of student and focuses on one particular early behavior shown to be a consistent early antecedent to a broad set of adolescent and adult diagnoses involving externalizing behaviors—namely, early aggressive and disruptive classroom behavior.

The first study looked at the effect of the game in first- and second-grade classrooms in 19 Baltimore public schools beginning in the 1985-1986 school year. In five poor to lower-middle-class, mainly African-American urban areas, three or four schools were grouped, and within each set, schools were randomly assigned to one of three conditions: the Good Behavior Game, a curriculum-and-instruction program directed at reading achievement, or the standard program.

When assessed in young adulthood, male participants in the game, particularly those who in first grade were more aggressive and disruptive, showed significantly less prevalence of the externalizing outcomes.

"There is a broad literature that overlaps with the self-control measures that Caspi and colleagues report, and a growing number of studies that show early interventions have a considerable impact on development," Kellam said.