ADHD affects 13.5% of boys in the US.
Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed childhood disorders, involving difficulty with focusing attention and remaining "on task," excessively impulsive behavior and extreme hyperactivity.
The Centers for Disease Control and Prevention (CDC) estimate that ADHD affects about 9.5% of children aged 3-17 in the US and can continue into adulthood. Diagnosis is based on clinical judgement rather than objective diagnostic markers.
Methylphenidate, the most commonly used medication, is more commonly known by its brand names Ritalin, Concerta, Medikinet and Equasym, among others. It has been used to treat ADHD for over 50 years, but the new research, which focuses on the benefits and harms, encourages caution in use.
A team led by Prof. Ole Jakob Storebø, clinical psychologist from the Psychiatric Research Unit in Region Zealand, Denmark, evaluated and summarized the findings from all of the available randomized trials of the drug.
Methylphenidate use has advantages and drawbacks
The study included data from 185 randomized controlled trials involving more than 12,000 children or adolescents. The studies were conducted mainly in the US, Canada and Europe, included males and females aged 3-18, and all compared methylphenidate with either a dummy pill or no intervention.
Methylphenidate was found to cause modest improvements in ADHD symptoms, general behavior and quality of life. There was strong evidence that methylphenidate improved teacher-rated behavior.
Analysis of adverse effects showed that children were more likely to experience sleep problems and loss of appetite while taking methylphenidate.
There was no evidence that methylphenidate was linked to serious - for example, life-threatening, adverse effects 0 but there was a 29% increase overall in non-serious effects, a 60% higher risk of sleep problems and a 266% greater risk of decreased appetite.
Fast facts about ADHD
- Around 5.9 million children in the US are estimated to have ADHD
- 13.5% of boys in the US have ADHD
- 5.4% of girls in the US have the disorder.
Weaknesses of the trials that were reviewed included the fact that the people involved could have been aware of which treatment the children were taking. There was also incomplete reporting of results in many cases, 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.
In Prof. Storebø's view, the results indicate a need to carry out long-term, large, better-quality randomized trials in order to determine the average effect of the drug more reliably.
Coauthor Dr. Camilla Groth points to a lack of clarity about who the drug will benefit and the poor quality of the evidence. She calls for this to be taken into consideration when prescribing methylphenidate. She recommends that doctors balance the pros and cons of prescribing it, and wants treatment to be monitored carefully.
Another coauthor Dr. Morris Zwi, consultant child and adolescent psychiatrist, adds:
"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. What we still need are large, well-conducted trials in order to clarify the risks versus the benefits for this widely used treatment."
The researchers urge clinicians and families not to rush to stop using methylphenidate, because if patients experience benefits without adverse effects, then there may be good clinical grounds to continue using it.
They call on patients and parents not to stop treatment or make any changes before discussing the issue with their health professional.
Earlier this year, Medical News Today reported on research linking ADHD with traumatic brain injury.