“The importance of this study is simply that it confirms that ADHD in children is not something to take lightly,” says Benjamin B. Lahey, PhD, a professor of epidemiology at the University of Chicago in Illinois, in an email.
The study is published in the October issue of the Archives of General Psychiatry.
ADHD is a behavioral disorder characterized by difficulty paying attention, impulsive behaviors, and hyperactivity. Up to 37% of adults with ADHD are also depressed, and studies have shown that when major depression occurs with ADHD, it starts earlier, lasts longer, and is often more severe than when it occurs on its own.
The new study comprised 125 kids diagnosed with ADHD when they were 4 to 6 years old and 123 ADHD-free kids for comparison. Researchers followed the children until they turned 18.
Children diagnosed with ADHD between the ages of 4 and 6 were at greater risk for depression between the ages of 9 and 18. Additionally, 12% of children and adolescents with ADHD and 1.6% of the ADHD-free kids said they had a specific suicide plan at least once during this time period.
More than 18% of children and adolescents with ADHD and 5.7% of their counterparts without ADHD attempted suicide at least once during the follow-up period.
Kids with ADHD who were most at risk for suicide or depression were girls, children, or adolescents whose mom was depressed, and those who displayed a lot of anxiety and behavioral issues.
Researchers categorized ADHD into three subtypes: inattentiveness, hyperactivity, and/or a combination of both. Those children with ADHD who exhibited a combination of inattention and hyperactivity were at increased risk for depression and attempted suicide, while children who experienced only inattentiveness were at risk for depression. ADHD marked by hyperactivity only was a risk factor for 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 behavior," the researchers conclude.