Drugs to boost mental ability in people with Alzheimer’s disease may have been hiding in plain sight after scientists found that medication for Attention Deficit Hyperactivity Disorder (ADHD) brings significant improvements to thinking.
Researchers from Imperial College said there was “good evidence” that ADHD medicines such as atomoxetine and guanfacine may also treat Alzheimer’s, and have called for large clinical trials.
The drugs work by boosting levels of a neurotransmitter called noradrenaline, which is crucial for mental processes such as attention, learning, memory, readiness for action and the suppression of inappropriate behaviours.
Disruption of the system producing noradrenaline happens early in Alzheimer’s, leading researchers to believe that drugs targeting the problem could help.
Although small trials have been carried out in the past, they never involved enough patients to be sure.
To get around the small numbers, Imperial pooled an analysis of 10 small trials involving a total of 1,300 patients and found that ADHD drugs boosted cognitive scores by a “small but significant” amount while reducing apathy to a larger extent.
The results are so encouraging that Imperial is running a trial at Charing Cross Hospital, in London, to see whether the ADHD drug guanfacine can help Alzheimer’s patients.
Results ‘certainly show promise’
Dr Michael David, of the UK Dementia Research Institute’s Care Research and Technology Centre at Imperial, said: “Current medications have small effects on symptoms including cognition. However, they do not slow the progress of the disease itself.
“We looked at how these test scores changed between the beginning of the trials and at the end, and compared the change across those in the group given the active drug and those in the placebo group.
“Overall, those in the drug group seemed to improve, or decline less, in terms of these scores than those in the placebo group. I think these results certainly show promise with regard to the potential benefits in targeting this neurotransmitter system.”
There are 944,000 people with dementia in the UK, a number expected to increase to more than one million by 2030 and more than 1.6 million by 2050.
Drugs that are already known to be safe are particularly appealing to researchers because they can be trialled quickly for other conditions and are more likely to pass through regulation.
Report ‘should stimulate further trials’
Commenting on the findings, Sian Gregory, the research information manager at the Alzheimer’s Society, said: “This promising new research could help to improve the lives of people living with Alzheimer’s disease in the future, helping to reduce the effect of common symptoms such as memory and thinking problems and improving apathy.
“Because drugs that act on the chemical messenger noradrenaline are already commonly used to treat disorders like ADHD and depression, clinical trials to assess their benefit for people with Alzheimer’s disease should be straightforward.”
David Smith, professor emeritus of pharmacology at the University of Oxford, said: “The report should stimulate further trials, in particular with combinations of these drugs with other symptomatic treatments.”
The research was published in the Journal of Neurology, Neurosurgery and Psychiatry.