Little scientific proof Ritalin effective, researchers discover
Studies played down negative side effects and role of placebos
OTTAWA - After a painstaking analysis of 62 studies of Ritalin treatment for attention deficit disorder, a team of Canadian researchers says it has found little scientific evidence the drug lives up to its reputation.
More than 200,000 Canadian schoolchildren take methyl-phenidate, the generic name for Ritalin, a stimulant drug prescribed to help them concentrate and control their impulsive behaviour. Many parents, teachers and doctors praise the drug for turning around the tumultuous lives of millions of young children.
Yet a meta-analysis published today in the Canadian Medical Association Journal says the clinical trials of the drug have often been biased and poorly constructed. For example, although patients may take Ritalin for years, most trials comparing the drug with a placebo lasted three weeks, with none lasting longer than seven months. In some cases, scientists studying Ritalin ignored or downplayed the impressions of schoolteachers, who thought children taking the drug were no better off than those taking a placebo. Finally, such adverse side effects as insomnia and loss of appetite have not been carefully measured.
"Collectively, these observations likely reflect a less than an ideal state of affairs given the long history of extensive, and ever increasing, use of methylphenidate for ADD particularly in North America for groups that now include pre-schoolers and adults," conclude the researchers, from the Children's Hospital of Eastern Ontario and the University of Ottawa.
For a disease that didn't officially exist before 1987, attention deficit disorder has been remarkably catching. An estimated 5% of children are affected.
Several years ago, the definition was expanded to the new name, attention deficit/hyperactivity disorder [AD/HD]. The symptoms include trouble concentrating, talking constantly, running around in a disruptive way, fidgeting and acting impulsively.
Surprisingly, little is known about how Ritalin tames these symptoms, but scientists agree it clearly works in the short term. A positive response to Ritalin, however, does not mean a child has AD/HD; stimulants can temporarily sharpen anyone's focus. Also, the drug does not raise IQ or remove the learning disabilities that often accompany AD/HD.
"Short-term managed behaviour -- that's important for a lot of kids, but it's not going to give them the skills that they need to manage for the rest of their lives, because when the medication wears off, they're back at square one and, in some cases, maybe a little worse off," says Toronto psychologist Lynda Thompson, co-author of The A.D.D. Book.
As a result, many people are seeking alternatives, including biofeedback and nutritional regimens. These have less dramatic results than Ritalin, but they make parents more comfortable.
Indeed, a University of British Columbia study, also published today in the CMAJ, raises concerns that many children who are prescribed Ritalin don't need it.
Download the studies on ritalin