A new Cochrane review has found 7 randomised controlled trials that investigate the efficacy of amphetamine derivatives against placebo or an active intervention.
Attention Deficit Hyperactivity Disorder (ADHD) is a childhood onset psychiatric disorder that can persist into adulthood in up to 50% of patients. From a clinical point of view, ADHD is characterized by hyperactivity, mood instability, irritability, difficulties in maintaining attention, lack of organization and impulsive behaviours. The presence of other disorders occurring at the the same time is also common, especially mood disorders and substance abuse. It seems that amphetamines could reverse the underlying neurological problems that feature in ADHD, and so improve ADHD symptoms.
The review found seven studies, which enrolled 1091 patients. These studies compared amphetamines to placebo and three of them also compared amphetamines with other drugs: guanfacine, modafinil and paroxetine. Three amphetamine derivatives were investigated: dexamphetamine, lisdexamphetamine and mixed amphetamine salts (MAS). Treatment length ranged from two to 20 weeks.
All amphetamines improved ADHD symptoms but overall they did not make people more likely to stay in treatment and were associated with a higher risk of treatment ending early due to adverse events. One type of amphetamine, mixed amphetamine salts, did, however, increase retention in treatment. The review found no evidence that higher doses worked better than lower ones. The review did not find any difference in effectiveness between immediate-release and sustained-release formulations. Therefore, it appears that short-term treatment with amphetamines reduces ADHD symptoms, but studies assessing the effects of amphetamines for longer periods of time are needed.
The reviewers conclude:
Amphetamines improved short-term ADHD symptom severity. Mixed amphetamine salts also increased retention in treatment. Amphetamines were associated with higher attrition due to adverse events. The short study length and the restrictive inclusion criteria limit the external validity of these findings. Furthermore, the possibility that the results of the included studies were biased was high, which could have led to an overestimation of amphetamine efficacy.
Castells X, Ramos-Quiroga JA, Bosch R, Nogueira M, Casas M. Amphetamines for Attention Deficit Hyperactivity Disorder (ADHD) in adults. Cochrane Database of Systematic Reviews 2011, Issue 6. Art. No.: CD007813. DOI: 10.1002/14651858.CD007813.pub2.
Dear Elf,
It is worth noting some very serious issues with this review.
Firstly, one has to agree that it is appropriate to label certain individuals as “mentally ill” and suffering from “ADHD”.
I don’t agree and neither does the British Psychological Society, as noted in its response to the DSM-V development: (free on the web as a PDF and written in June 2011).
Extracts from the response (page 4):
“We believe that classifying these problems [which include ADHD] as ‘illnesses’ misses the relational context of problems and the undeniable social causation of many such problems.
For psychologists, our well-being and mental health stem from our frameworks of
understanding of the world, frameworks which are themselves the product of the
experiences and learning through our lives”. “We are very
concerned at the increasing use of this diagnosis [ADHD] and of the increasing use of
medication for children, and would be very concerned to see these increase further”.
Secondly, amphetamine is a drug of addiction and abuse, I question the ethics of any doctor who prescribes any amphetamine derivative or other psychostimulant.
Thirdly, 3/7 of the studies considered valid and therefore included in this review were carried out by one or more of the following people: Joseph Biederman, Thomas J. Spencer, and Timothy E. Wilens. These Harvard psychiatrists were disciplined by Harvard in 2011. They were found to not to have declared significant funding (totalling $4.2 million) received from pharmaceutical companies in 7 years up to 2008.
Fourthly, 4/5 of the reviewers have been funded by pharmaceutical companies, something they disclosed in the review.
Best Wishes,
Patricia