Young children who have attention-deficit/hyperactivity disorder (ADHD) appear to be at greater risk for adolescent depression and/or suicide attempts five to 13 years after diagnosis, according to a new study.

Researchers investigated 125 children between the ages of four and six years who met medically diagnosed criteria for ADHD, and 123 demographically matched children without ADHD in Chicago and Pittsburgh to determine if young children diagnosed with ADHD face a higher risk of depression and attempted suicide.

Children in both groups underwent follow-up assessments until the age of 18 years. The study’s authors found that children diagnosed with ADHD between the ages of four and six years were at greater risk for depression between the ages of nine and 18 years.

Additionally, 17 of 248 children had reported having a specific suicidal plan at least once during this same time-period, which included 12 per cent of children and adolescents with ADHD and 1.6 per cent of children and adolescents in the comparison group.

“A total of 18.4 per cent of children and adolescents with ADHD and 5.7 per cent of comparison children and adolescents made at least one suicide attempt by assessment year 14.

“Our findings indicate that young children with ADHD are at high risk for both single and recurrent episodes of adolescent depression and for suicidal behaviour, even controlling for a history of major depression in their mothers and other demographic and methodologic predictors of these outcomes,” the researchers commented.

Maternal depression, combined with child emotional and behavioural problems at four-to-six years, predicted depression and suicidal behaviours in children with ADHD. Additionally, the findings have indicated that girls are at a greater risk for depression and suicide attempts.

The authors also categorised ADHD into three subtypes and found that each one – inattentiveness, hyperactivity and/or a combination of the two – predicted somewhat different outcomes.

While children who have a combination of inattention and hyperactivity predicted both depression and attempted suicide, children who experience only inattentiveness predicted only depression. Children showing only hyperactivity predicted suicide attempts but not depression.

“These findings suggest that it is possible to identify children with ADHD at very young ages who are at very high risk for later depression and suicidal behaviour,” the study’s authors concluded. “Considered in light of what is already known about the antisocial outcomes of childhood ADHD and their risk for unintentional injury, it would not be premature to test early prevention programmes designed to reduce both serious behavioural and affective sequelae of ADHD in early childhood.”