Do drugs for attention deficit hyperactivity disorder (ADHD) help steer kids away from cigarettes? Or do they actually make youngsters with ADHD more likely to smoke? In a new report, researchers say they might have found some signs of the former, but they also acknowledge that the evidence is extremely weak.
"The idea of whether treatment for ADHD affects the risk for other conditions is a really interesting thing and there is a lot of back and forth," said Dr Paul Hammerness of Harvard Medical School in Boston, who led the research.
About 2.7 million children and teens in the US take stimulants for ADHD, such as Novartis' Ritalin, Shire's Adderall and Janssen's Concerta.
Studies in rats have shown that giving the animals stimulants might whet their appetite for cocaine later on. But there have been mixed findings on the link between stimulants, substance abuse and smoking in humans.
How the study was done
In the new study, which was funded by Janssen, Dr Hammerness analysed 154 adolescents with ADHD who used Concerta (extended-release methylphenidate). At a mean follow-up of 10 months, about 7% of the teens or pre-teens reported smoking.
That was a smaller proportion than the 20% smoking rate seen in a nonsimultaneous cohort of adolescents with ADHD who were not taking stimulants.
But when the researchers accounted for differences is behavioural problems between the two groups, the gap in smoking rates disappeared.
Dr Hammerness, who has ties to several manufacturers of ADHD medications, said no firm conclusions could be drawn from his study, which was published online in The Journal of Pediatrics.
"You can't conclude anything from the study, nope," he said. "This is the nature of the beast."
But he also said that placebo-controlled studies are hard to do because not treating children with ADHD for extended periods could be considered unethical.
(Reuters Health, August 2012)
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