Short-term use of amphetamines can improve ADHD symptoms in adults

Giving amphetamines to adults with Attention Deficit Hyperactivity Disorder (ADHD) can help them control their symptoms, but the side effects mean that some people do not manage to take them for very long. These conclusions were drawn by a team of five researchers working at Girona and Barcelona Universities in Spain, and published in a new Cochrane Systematic Review.

Attention Deficit Hyperactivity Disorder (ADHD) is a childhood onset disorder, but half of people with it find that the symptoms of hyperactivity, mood instability, irritability, difficulties in maintaining attention, lack of organization and impulsive behaviours persist into adulthood. "We wanted to see whether could reverse the underlying that feature in ADHD, and so improve ADHD symptoms," says Xavier Castells, who led the study and works in the Unit of at University of Girona.

After searching through medical literature, they identified seven studies, which had enrolled a total of 1091 participants in clinical trials. The three amphetamine based medicines they considered (dextroamphetamine, lisdexamphetamine and mixed amphetamine salts (MAS)) all reduced ADHD symptoms, although there was no evidence that higher doses worked better than lower ones. The researchers did not find any difference between in effectiveness between formulations that release the amphetamines rapidly, and those that have a sustained-release.

While there was evidence that people taking amphetamines drop out of treatment due to adverse events slightly more than those on placebo controls, the researchers were keen to point out that only 9% of people taking amphetamines withdrew from treatment. Looking at the different formulations of amphetamines, those on MAS had lower drop-out rates than those on other versions of the drug. Furthermore, most studies had a duration of between 2 and 7 weeks, therefore precluding the possibility of drawing conclusions regarding amphetamine's efficacy and safety in the long-term.

In many clinical trials, doctors randomly allocate some patients to 'treatment group' and give them the active medication, while others are placed in a 'control group' and receive a placebo – a treatment that looks and feels like the real thing, but has no active ingredient in it. The idea is that the patient doesn't know which one they are on. This helps researchers determine how much of any apparent treatment effect is actually due to the therapy, and how much is due to other factors unrelated to drug effects such as the person believes regarding the efficacy of the intervention or the natural history of the disease. This experimental system only works, though, if the patients have no idea which group they are in. "One of the problems with trying to make sense of this research is that you cannot do a properly controlled study because the amphetamines have such a distinct set of effects. Patients instantly know whether they are on the treatment or the placebo, so you have to be more cautious about the way you interpret the data," says Castells.

"Given that other drugs, like atomoxetine or methylphenidate, have also been shown to reduce ADHD symptoms in adults, it would be of great interest to compare the efficacy of amphetamines to these interventions," says Castells.

More information: 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

add to favorites email to friend print save as pdf

Related Stories

Adult ADHD linked with dopamine levels

Aug 09, 2007

Adults with attention-deficit/hyperactivity disorder have a reduced response to the drug Ritalin, U.S. government scientists have found.

Recommended for you

Suicide risk falls substantially after talk therapy

9 hours ago

Repeat suicide attempts and deaths by suicide were roughly 25 percent lower among a group of Danish people who underwent voluntary short-term psychosocial counseling after a suicide attempt, new Johns Hopkins Bloomberg School ...

Brains transform remote threats into anxiety

Nov 21, 2014

Modern life can feel defined by low-level anxiety swirling through society. Continual reports about terrorism and war. A struggle to stay on top of family finances and hold onto jobs. An onslaught of news ...

Mental disorders due to permanent stress

Nov 21, 2014

Activated through permanent stress, immune cells will have a damaging effect on and cause changes to the brain. This may result in mental disorders. The effects of permanent stress on the immune system are studied by the ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.