Benefits and harms of methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD)

This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library 2015, Issue 11

Review question:
We reviewed the evidence of the effects of methylphenidate on the behavior of children and adolescents with ADHD.
Background:
ADHD is one of the most commonly diagnosed and treated childhood psychiatric disorders. Children diagnosed with ADHD find it hard to concentrate. They are often hyperactive (fidgety, unable to sit still for long periods) and impulsive (doing things without stopping to think). ADHD can make it difficult for children to do well at school, because they find it hard to follow instructions and to concentrate. Their behavioral problems can interfere with their ability to get on well with family and friends, and they often get into more trouble than other children. Methylphenidate is the drug most often prescribed to treat children and adolescents with ADHD.

Study characteristics:
We found 185 randomized controlled trials(RCTs; studies in which participants are randomly assigned to one of two or more treatment groups), involving12,245 children or adolescents with a diagnosis of ADHD.  Most of the trials compared methylphenidate to a placebo - something designed to look and taste the same as methylphenidate but with no active ingredient. Most trials were small and of low quality. Treatment generally lasted an average of 75 days (range 1 to 425 days), making it impossible to assess the long-term effects of methylphenidate. Seventy-two of the 185 included trials (40%) were funded by industry.

The evidence is current to February 2015.

Key results:
Findings suggest that methylphenidate might improve some of the core symptoms of ADHD - reducing hyperactivity and impulsivity, and helping children to concentrate. Methylphenidate might also help to improve the general behavior and quality of life of children with ADHD. However, we cannot be confident that the results accurately reflect the size of the benefit of methylphenidate.

The evidence in this review of RCTs suggests that methylphenidate does not increase the risk of serious (life threatening) harms when used for periods of up to six months. However, taking methylphenidate is associated with an increased risk of non-serious harms such as sleeping problems and decreased appetite.

Quality of the evidence
The quality of the evidence was very low for all outcomes. It was possible for people in the trials to know which treatment the children were taking, the reporting of the results was not complete in many trials and for some outcomes the results varied across trials. These considerations limit our confidence in the overall results of the review.