Over the past four years, around 40 per cent more children are being given a powerful stimulant drug, such as Ritalin, for ADHD (attention-deficit/hyperactivity disorder). But now, the experts fear that parents are being deliberately misled regarding the efficacy and safety of these drugs.
The explosion in the ADHD drugs market can be traced back to 1999, with the publication of the Multi-modal Treatment Study of Children with ADHD (MTA). This study, which tracked 485 children diagnosed with ADHD, concluded that drugs were an effective long-term therapy and better than other approaches such as talk therapy. Within weeks of MTA publi-cation, the manufacturers of drugs such as Ritalin, Adderall and Concerta were circulating copies of the report to doctors across the US and Europe.
Since then, ADHD drug prescriptions have grown dramatically year after year, with nearly 40 million prescriptions written in the US alone last year.
Yet, there are growing concerns that doctors-and parents-have been misled by members of the MTA research team who have been accused of putting an overly optimistic spin on their findings and downplaying the drugs' safety issues.
Chief critic of the MTA study is psychologist William Pelham, from the State University of New York in Buffalo, who was involved in the field-work. Dr Pelham says: "The stance the group took in the first paper was so strong that [they] are embarrassed to say they were wrong . . ."
In effect, the MTA had no data to justify the claim that ADHD drugs offer a long-term solution; at the time, they had only just started the follow-ups and had tracked the children for less than a year. The full, eight-year, follow-up ended last year, by which time, the MTA researchers could find no differences in behaviour between children receiving medication (since 1999) and those who weren't.
Despite this, the highly influential US National Institute of Mental Health (NIMH) continues to stand by the initial view that the drugs offer long-term help. Last year, it issued a press release with the headline "Improvement Following ADHD Treat-ment Sustained in Most Children", a claim unsupported by the latest data, which the NIMH had already seen.
The MTA study's eight-year follow-up data have now been published (J Am Acad Child Adolesc Psychiatry, 2009 Mar 23; Epub ahead of print), and confirm the initial announcement made last year: any benefits of drug therapy disappear within 14 months and, even at that time, led to no differences in behav-iour and ability to concentrate between those taking an ADHD drug and those who never had.
Dr Pelham is concerned that some of his colleagues in the MTA study knew early on-possibly as early as 1999-that the drugs offered no long-term benefit. In one interview, he said that his colleagues had "repeatedly sought to explain away evidence that challenged the long-term usefulness of medication. When their explana-tions failed to hold up, they reached for new ones" (Washington Post, March 27, 2009; page A01).
The latest MTA report also suggests that the drugs could be harming the children's physical development. The children who took an ADHD drug for 36 months or more were, on average, 1 inch (2.5 cm) shorter and 6 lb (2.7 kg) lighter. But this, too, has been reinterpreted by the NIMH. In the above-mentioned 2008 press release, it said that the children not on medication "grew somewhat larger".
Dr Pelham has been attacked by co-author Dr Peter Jensen, a former director of the NIMH who continues to speak on its behalf. He claims that Pelham was the only MTA researcher to take away "the silly message" that the study questioned the long-term effectiveness of the drugs.
But this is not true. Brooke Molina, associate professor of psychiatry and psychology at the University of Pitts-burgh, says the data don't "support that children who stay on medication longer than two years have better outcomes than children who don't". In an e-mail to Dr Pelham and others, she said that the academic reviewers "thought we were bending over backward (inappropriately) to dismiss the failure to find medication effects at eight years".
Instead of seeking a drugs approach, parents should be looking to improve their ADHD child's levels of essential fatty acids (EFAs). EFAs play an essential role in brain structure and function. Two of them-arachidonic acid (AA) and docosahexaenoic acid (DHA)-play a major role in the brain and eye, constituting 20 per cent of brain dry weight and more than 30 per cent of the retina. Two other EFAs-eicosapentaenoic acid (EPA) and dihomo-gamma-linolenic acid (DGLA)-are crucial for normal brain development, but also have a minor structural role.
These absolutely essential EFAs cannot be synthesized by the body, so must be supplied in the diet: DGLA and AA are omega-6 fatty acids; EPA and DHA are omega-3 fats. Both AA and DHA are termed 'long-chain polyunsaturated fatty acids' (LC-PUFAs) and can usually be synthesized from their EFA precursors. These fatty acids are critically important as they contribute to a complex group of highly biologically active compounds such as prostanoids (prostaglandins, thromboxanes and prostacyclins, among others) and leukotrienes. These compounds perform numerous regulatory functions in both the brain and body.