The latest research from the U.S. says the long-term use of drugs such as Ritalin and Concerta for the treatment of children with Attention Deficit Hyperactivity Disorder (ADHD) is not effective.
The study also suggests that the long-term use of the powerful drugs could in fact stunt children's growth and says the benefits of the drugs have been exaggerated.
The study called the 'Multimodal Treatment Study of Children with ADHD' has been monitoring the treatment of 600 children across the U.S. since the 1990s; it reveals that drugs such as Ritalin are no more effective than therapy over a three year treatment period.
In 1999, the study concluded that after one year medication worked better than behavioural therapy for ADHD and that finding influenced medical practice on both sides of the Atlantic, and prescription rates multiplied.
Professor William Pelham of the University of Buffalo, the study's co-author, says the beneficial impact of the medications were exaggerated in the first study and the idea that if children were medicated longer they would have better outcomes was not the case.
Professor Pelham says in the long run there are "no beneficial effects" of medication and the impact was instead seemingly negative as the children had a substantial decrease in their rate of growth.
The National Institute for Clinical Excellence (NICE) in Britain is currently revising the treatment guidelines for ADHD and are devising new strategies which will involve training for parents as well as "behavioural interventions".