Powerful stimulant drugs such as Ritalin work for only the first few months on children with ADHD (attention deficit, hyperactivity disorder).
At best, the good effects last for 14 months, at which point the drugs should be stopped, a major new study has concluded.
The MTA (Multimodal Treatment Study of Children with ADHD) tracked 485 children for eight years, and those who were still taking a stimulant drug at the end of that period were showing the same levels of inattention and hyperactivity as those who had never taken a drug. Most of the children had taken the drugs for only the first 14 months, and had then stopped.
The MTA researchers conclude that their finding raises "questions about whether medication treatment beyond two years continues to be beneficial or needed at all."
The latest conclusion is very different from the very positive one the same research group reached in 1999 when it advocated the long-term use of ADHD drugs such as Ritalin, Adderall and Concerta.
A critic of the MTA research is William Pelham, of the State University of New York Buffalo, who took part in the field work.
He said this week: "The stance the group took in the first paper was so strong that the people are embarrassed to say they were wrong and we led the whole field astray. If 5 per cent of families in the country are giving a medication to their children, and they don't realize it does not have long-term benefits, but might have long-term risks, why should they not be told?"
(Source: Journal of the American Academy of Child & Adolescent Psychiatry, 2009, March 23; published online: doi: 10.1097/CHI.0b013e31819c23d).