Children with chronically elevated externalizing symptoms, such as behavioral problems, or internalizing symptoms, such as mental health concerns, have an increased risk for poor economic and social outcomes in adulthood, data from a new study suggest.
Children with comorbid externalizing and internalizing symptoms were especially vulnerable to long-term economic and social exclusion.
“Research has mostly studied the outcomes of children with either behavioral problems or depression-anxiety problems. However, comorbidity is the rule rather than the exception in clinical practice,” senior author Massimilliano Orri, PhD, an assistant professor of psychiatry at McGill University and clinical psychologist with the Douglas Mental Health University Institute, both in Montreal, said in an interview.
“Our findings are important, as they show that comorbidity between externalizing and internalizing problems is associated with real-life outcomes that profoundly influence a youth’s chances to participate in society later in life,” he said.
The study was published in JAMA Network Open.
Dr. Orri and colleagues analyzed data for 3,017 children in the Quebec Longitudinal Study of Kindergarten Children, a population-based birth cohort that enrolled participants in 1986-1987 and 1987-1988 while they were attending kindergarten. The sample included 2,000 children selected at random and 1,017 children who scored at or above the 80th percentile for disruptive behavior problems.
The research team looked at the association between childhood behavioral profiles and economic and social outcomes for ages 19-37 years, including employment earnings, receipt of welfare, intimate partnerships, and having children living in the household. They obtained the outcome data from participants’ tax returns for 1998-2017.
During enrollment in the study, the children’s teachers assessed behavioral symptoms annually for ages 6-12 years using the Social Behavior Questionnaire. Based on the assessments, the research team categorized the students as having no or low symptoms, high externalizing symptoms only (such as hyperactivity, impulsivity, aggression, and rule violation), high internalizing symptoms only (such as anxiety, depression, worry, and social withdrawal), or comorbid symptoms. They looked at other variables as well, including the child’s sex, the parents’ age at the birth of their first child, the parents’ years of education, family structure, and the parents’ household income.
Among the 3,017 participants, 45.4% of children had no or low symptoms, 29.2% had high externalizing symptoms, 11.7% had high internalizing symptoms, and 13.7% had comorbid symptoms. About 53% were boys, and 47% were girls.
In general, boys were more likely to exhibit high externalizing symptoms, and girls were more likely to exhibit high internalizing symptoms. In the comorbid group, about 82% were boys, and they were more likely to have younger mothers, come from households with lower earnings when they were ages 3-5 years, and have a nonintact family at age 6 years.
The average age at follow-up was 37 years. Participants earned an average of $32,800 per year at ages 33-37 years (between 2013 and 2017). During the 20 years of follow-up, participants received welfare support for about 1.5 years, had an intimate partner for 7.4 years, and had children living in the household for 11 years.
Overall, participants in the high externalizing and high internalizing symptom profiles – and especially those in the comorbid profile – had lower earnings and a higher incidence of annual welfare receipt across early adulthood, compared with participants with low or no symptoms. They were also less likely to have an intimate partner or have children living in the household. Participants with a comorbid symptom profile earned $15,031 less per year and had a 3.79-times higher incidence of annual welfare receipt.