Uncertainties remain about the effect of a widely used medicine on attention deficit hyperactivity disorder symptoms, according to a review by a well-respected research organisation.
Methylphenidate, more commonly known by its brand names Ritalin, Concerta, Medikinet and Equasym has been used to treat ADHD for more than 50 years.
A team of researchers from the Cochrane Collaboration evaluated findings from all of the available trials on the widely used drug.
The review included data from 185 trials involving more than 12,000 children or adolescents. The studies were conducted mainly in North America and Europe, and all compared methylphenidate with either a placebo or no intervention.
The researchers found methylphenidate led to modest improvements in ADHD symptoms, general behaviour, and quality of life.
Analysis of adverse effects showed that children were also more likely to experience sleep problems and loss of appetite while taking methylphenidate, according to the review, which was published by the Cochrane Library.
However, the researchers said their confidence in the trial results was very low.
It was apparent that it would have been possible for people involved in the trials to have been aware of which treatment the children were taking. In addition, the reporting of results was not complete in many of the trials, and for some analyses there was variation 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 evidence is important for health professionals and parents of children with ADHD”
Lead study author Professor Ole Jakob Storebø, a clinical psychologist from Denmark, said: “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.”
Study co-author, Dr Morris Zwi, a consultant child and adolescent psychiatrist from the Islington Child and Adolescent Mental Health Service, added: “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,” he said.
“What we still need are large, well-conducted trials in order to clarify the risks versus the benefits for this widely used treatment,” he noted.
However, the researchers urged clinicians not to rush to discontinue using methylphenidate.
Dr Zwi added: “If a child or young person has experienced benefits without experiencing adverse effects, then there may be good clinical grounds to continue using it.”