A recent Cochrane review has found that serious adverse events occur for about 1% of children and adolescents treated with the stimulant methylphenidate (brand name Ritalin)—a commonly used drug for children diagnosed with ADHD. Ole Jakob Storebø led the research at the Child and Adolescent Psychiatric Research Unit, Region Zealand, Roskilde, Denmark.
The adverse events rated as “serious” included psychotic symptoms, cardiac arrhythmia, and death. Storebø and the other researchers noted the high prevalence of other side effects as well, such as insomnia and appetite suppression, which occurred in more than half of the children taking the drug.
The authors also write that because the included studies were rated as having low methodological quality, it is difficult to estimate the number of children experiencing side effects—but it is likely to be even higher since the methodological bias in the included studies was to under-report side effects. According to the authors:
“We found that studies funded by pharmaceutical companies had a much lower proportion of both serious and non-serious adverse events. This is worrying, as it shows that adverse events are underestimated in industry-sponsored studies, conﬁrming ﬁndings from previous systematic reviews.”
The Cochrane Collaboration is a group of international researchers conducting rigorous reviews and analyses of published and unpublished data. The authors are required to be free of financial conflicts of interest (such as receiving money from the pharmaceutical industry) as a way of reducing bias. Cochrane reviews are considered to be the gold standard of analysis.
The current review synthesized the data from 260 studies and 2,283,509 participants. The included studies were of all types, including randomized and non-randomized designs. For instance, some of the included studies were longitudinal cohort studies, which examine large groups of people over long time periods.
As reported previously at Mad in America, children taking methylphenidate were also about twice as likely as those in the placebo group to experience hallucinations as a side effect of the drug. That study found that about 1-2% of children taking methylphenidate experienced hallucinations.
The evidence for the effectiveness of methylphenidate at treating ADHD has also been described in rigorous Cochrane reviews as being of “very low quality” and at “high risk of bias.” The authors of the current report urge that prescribers be more cautious about prescribing stimulants for ADHD, and closely monitor for adverse events.
Storebø, O. J., Pedersen, N., Ramstad, E., Kielsholm, M. L., Nielsen, S. S., Krogh, H.B. . . . Gluud, C. (2018). Methylphenidate for attention deficit hyperactivity disorder (ADHD) in children and adolescents – assessment of adverse events in non-randomised studies. Cochrane Database of Systematic Reviews, Issue 5, Art. No.: CD012069. DOI: 10.1002/14651858.CD012069.pub2. (Link)