Older teens and adults with attention deficit disorder are much less likely to commit a crime while on ADHD medication, a provocative study from Sweden found.
It also showed in dramatic fashion how much more prone people with ADHD are to break the law — four to seven times more likely than others.
The findings suggest that Ritalin, Adderall and other drugs that curb hyperactivity and boost attention remain important beyond the school-age years and that wider use of these medications in older patients might help curb crime.
"There definitely is a perception that it's a disease of childhood and you outgrow your need for medicines," said Dr. William Cooper, a pediatrics and preventive medicine professor at Vanderbilt University in Nashville. "We're beginning to understand that ADHD is a condition for many people that really lasts throughout their life."
He has researched ADHD but had no role in the new study, which was led by Paul Lichtenstein of the Karolinska Institute in Stockholm. The findings were published in Thursday's New England Journal of Medicine.
About 5 percent of children in the U.S. and other Western countries have attention deficit hyperactivity disorder, which can cause impulsive behavior and difficulty paying attention. Many youngsters are given medication to help them sit still and focus in school. Some people have symptoms into adulthood.
"It's well known that individuals with ADHD have much higher rates of criminality and drug abuse than people without ADHD," but the effect of treatment on this is not well known, Lichtenstein said.
Using Swedish national registers, researchers studied about 16,000 men and 10,000 women ages 15 and older who had been diagnosed with ADHD. The country has national health care, so information was available on all drugs prescribed.
Court and prison records were used to track convictions from 2006 through 2009 and see whether patients were taking ADHD drugs when their crimes were committed. A patient was considered to have gone off medication after six months or more with no new prescription.