Despite large amounts of research, some experts remain uncertain about the effectiveness of methylphenidate (Ritalin, Concerta, Medikinet and Equasym), a widely used ADHD medication. Based on evidence of increased sleeplessness and loss of appetite in children, researchers are encouraging more caution in the use of this medication.
A team of Cochrane researchers has carefully evaluated and summarized the findings from all of the available randomized trials of this widely used drug. Their confidence in the trial findings, however, was very low, and they report that better-conducted studies are needed.
“This evidence is important for health professionals and parents of children with ADHD. Our expectations of this treatment are probably greater than they should be, and whilst our review shows some evidence of benefit, we should bear in mind that this finding was based on very low-quality evidence,” said co-author Dr. Morris Zwi, consultant child and adolescent psychiatrist.
“What we still need are large, well-conducted trials in order to clarify the risks versus the benefits for this widely used treatment.”
ADHD is estimated to affect about 5 percent of children, and diagnosis is based on clinical judgement rather than objective diagnostic markers. Symptoms include difficulty focusing attention and remaining “on task,” excessively impulsive behavior, and extreme hyperactivity.
The review included data from 185 randomized controlled trials involving more than 12,000 children and teens. The studies, which were conducted mainly in the U.S., Canada, and Europe, compared methylphenidate with either a dummy pill or no intervention.
According to the trials, methylphenidate led to modest improvements in ADHD symptoms, general behavior, and quality of life. On the other hand, the analysis showed that children were more likely to experience sleep problems and loss of appetite while taking methylphenidate.
But the researchers’ confidence in all the trial results was very low. After assessing the details of the various trials, it was apparent that it would have been possible for people involved in the studies to have known which treatment the children were taking.
In addition, the reporting of results was not complete in many of the trials, and there were some conflicting conclusions among trial results.
Based upon this information, the researchers urge clinicians to be cautious in prescribing methylphenidate, and to weigh up the benefits and risks more carefully.
“This review highlights the need for long-term, large, better-quality randomized trials so that we can determine the average effect of this drug more reliably,” said Professor Ole Jakob Storebø, clinical psychologist from the Psychiatric Research Unit in Region Zealand, Denmark.
Co-author Camilla Groth, M.D., added, “This review shows very limited quality evidence for the effects of methylphenidate on children and adolescents with ADHD. Some might benefit, but we still don’t know which patients will do so.
“Clinicians prescribing methylphenidate must take account of the poor quality of the evidence, monitor treatment carefully, and weigh up the benefits and adverse effects.”
The researchers also suggest that doctors and families not rush to discontinue using methylphenidate. “If a child or young person has experienced benefits without experiencing adverse effects, then there may be good clinical grounds to continue using it. Patients and their parents should discuss any decision to stop treatment with their health professional before doing so,” said Zwi.
An abridged version of the Cochrane Review is published in the journal BMJ.