Children with attention-deficit hyperactivity disorder are two to three times more likely than children without the disorder to develop serious substance abuse problems in adolescence and adulthood, according to a study by UCLA psychologists and colleagues at the University of South Carolina.
"This greater risk for children with ADHD applies to boys and girls, it applies across race and ethnicity — the findings were very consistent," said Steve S. Lee, a UCLA assistant professor of psychology and lead author of the study. "The greater risk for developing significant substance problems in adolescence and adulthood applies across substances, including nicotine, alcohol, marijuana, cocaine and other drugs."
Lee and his colleagues analyzed 27 long-term studies that followed approximately 4,100 children with ADHD and 6,800 children without the disorder into adolescence and young adulthood — in some cases for more than 10 years. These carefully designed, rigorous and lengthy studies, Lee said, are the "gold standard" in the field.
The research by Lee and his colleagues, the first large-scale comprehensive analysis on this issue, is published online this week in the journal Clinical Psychology Review and will appear in a print edition later this year.
The researchers combined all the published studies that met rigorous criteria and analyzed them together. They found that children with ADHD were at greater risk for serious problems such as addiction, abuse and trying to quit but being unable to, Lee said.
"Any single study can be spurious," he said, "but our review of more than two dozen carefully designed studies provides a compelling analysis."
ADHD is common, occurring in approximately 5 percent to 10 percent of children in the U.S., and figures in many other industrialized countries with compulsory education are comparable, according to Lee.
Symptoms of the disorder are common in children and include being easily distracted, fidgeting, being unable to complete a single task and being easily bored. However, to receive a diagnosis of ADHD, a child must have at least six of nine symptoms of either hyperactivity or inattention, and the child's behavior must be causing problems in his or her life. The vast majority of children with ADHD have at least six symptoms in both categories, Lee said.
In addition, the symptoms must have started before age seven, must be present in multiple settings — at home and school, for example — and must be adversely affecting functioning. They must not be explainable by any medical condition or any other mental disorder.
As children with ADHD enter adolescence and adulthood, they typically fall into three groups of roughly equal size, Lee said: one-third will have significant problems in school and socially; one-third will have moderate impairment; and one-third will do reasonably well or have only mild impairment.
Parents should monitor their children, said Lee, who noted that early intervention with a mental health professional is often helpful. A diagnosis of ADHD must be made by a mental health professional such as a child psychologist or psychiatrist and not by a parent or teacher.