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.
For comparison purposes, researchers matched each ADHD patient with 10 similar people without the disorder from the general population.
•About 37 percent of men with ADHD were convicted of at least one crime during that four-year period, compared with just 9 percent of men without ADHD. For women, the crime rates were 15 percent with ADHD and 2 percent without it.
•Use of ADHD medicines reduced the likelihood of committing a crime by 32 percent in men and 41 percent in women.
The crimes were mostly burglaries or thefts. About 4,000 of more than 23,000 crimes committed were violent. ADHD medication use reduced all types of crime, Lichtenstein said.
Cooper called the results striking. “I was surprised by the magnitude of the effect of the medications and the fact that it was so consistent across all the analyses they did,” such as the type of drug being used and the types of crimes committed, he said.
The Swedish Research Council, the U.S. National Institute of Child Health and Human Development, the Wellcome Trust and other agencies paid for the research.
ADHD medicines may help people organize their lives better and reduce impulsive behavior. They also bring a patient into counseling and health care, said Philip Asherson, a professor at the Institute of Psychiatry at King’s College London.