Early family intervention alters preschoolers' biological response to stress

Oct 2 2007

Children with older delinquent siblings are at high risk for becoming juvenile delinquents themselves.

Researchers have been studying family interventions that prevent young high-risk children from following in the footsteps of their older siblings. Now a new study shows that a non-medical early family intervention that improves caregiving also results in important changes in children's biological response to stress.

Delinquent adolescents and highly aggressive children have been shown to have abnormal stress responses, especially in social situations. They appear to be less tuned in to social cues and they are not as sensitive to positive reinforcement as normally developing children, explains Laurie Miller Brotman, Ph.D., the lead author of the study and the Corzine Family Associate Professor of Child and Adolescent Psychiatry at NYU School of Medicine.

A family intervention that results in an adaptive stress response in young high-risk children may prevent delinquency and psychiatric illness later in life.

“Our findings demonstrate the powerful influence of the caregiving environment on children's biology,” says Dr. Brotman. “We have known for some time that parents play an important role in how young children behave. We have shown that parents of delinquent youth can improve their parenting and these changes result in lower rates of problems in their young children. We have now documented that a program that improves parenting and children's behavior also leads to biological changes that are consistent with more adaptive non-delinquent behaviors.”

“We are really excited by these findings,” says Dr. Brotman, who is also Director of the Institute for Prevention Science at NYU Child Study Center “They suggest that antisocial behavior isn't hard wired and parents can be part of the solution.”

The new study is published in the October issue of Archives of General Psychiatry.

The connection between the stress response and the caregiving environment has been well established in animal studies. The amount of nurturing that rat pups receive from their mothers in the form of licking and grooming in infancy has been shown to alter the stress response with lasting effects over the life cycle. However, until now, no experimental studies in humans have established this connection.

“This was the first study to look for a cause-and-effect relationship between parenting and children's stress response, and the results tell us that there is such a relationship," says Daniel S. Pine, M.D., Chief of the Section on Development and Affective Neuroscience of the National Institute of Mental Health, and a co-author of the study. "It brings home the importance of early intervention with families of children at high-risk for antisocial behavior."

“The long-term consequences of the change in the cortisol response among the at-risk children in the study isn't known, but the results provide further evidence that early, intervention can have a profound effect on children,” says Dr. Brotman.

“We have already documented that an early family intervention leads to important benefits for children at very high risk for a multitude of negative outcomes. Findings from this new study show that the effects are even greater in scope than we had imagined,” says Dr. Brotman. “This means that we may be underestimating the potential benefits from investments in early family intervention for high-risk children. Policy makers should consider the possibility that by investing in evidence-based family interventions, they may have the potential to change children's biological make up as well as their mental health and behavior.”

Dr. Brotman and her colleagues evaluated whether a program designed to prevent antisocial behavior in high risk preschoolers could alter the children's biological response to a stressful social situation. Participating families had a preschooler and an adolescent who was adjudicated for a delinquent act in family court in New York City between 1997 and 2002.

Ninety-two families participated in the study. Nearly half of the parents had not completed high school and nearly 60 percent of the families had household incomes under $15,000. A majority of the parents had suffered with depression or anxiety and had experienced numerous negative life events in addition to the adjudication of their teenage child.

Families were randomized to a family intervention or a no-intervention condition. The family intervention included 22 group sessions for parents and preschoolers and 10 home visits delivered by mental health professionals over an 8-month period. Parents learned to use nonharsh, consistent, and appropriate disciplinary tactics, be less critical, and use positive reinforcement, among other strategies. Preschoolers learned to socialize with peers, to identify feelings and to follow rules.

Children's stress response was measured at home and before and after a socially stressful situation. Cortisol levels in saliva were measured before and after the children entered into an unfamiliar peer group. Normally developing, non-aggressive children are expected to show an increase in cortisol in anticipation of a social stressor.

For example, well-adjusted children show increased cortisol during the first few days of preschool. In this sample of high-risk children, as a group they did not show this expected pattern prior to intervention.

Following the family intervention, compared to children in the control group, children in the intervention group showed an increase in cortisol levels in anticipation of playing with a group of unfamiliar peers. As a result of the family intervention, children displayed a normal cortisol response relative to the control children who continued to show a pattern that resembles what has been found in older delinquent youth. Dr. Brotman and colleagues are studying these children and their older siblings during adolescence.