ADHD Drugs May Also Treat Alzheimer’s

There is “good evidence” that drugs to treat attention deficit hyperactivity disorder (ADHD) may also successfully treat key aspects of Alzheimer’s disease, according to an analysis of pooled data from available research, published online at the ‘Journal of Neurology Neurosurgery & Psychiatry’.

According to the researchers, clinical trials of noradrenergic drugs, including antidepressants and drugs to treat high blood pressure and ADHD, are now warranted.

Noradrenergic drugs target the neurotransmitter noradrenaline, also called norepinephrine, which is released by a network of specialized noradrenergic neurons. That network is critical for arousal and many cognitive processes, such as attention, learning, memory, preparing for action, and suppressing inappropriate behaviors.

The noradrenergic alteration occurs in the early phases of Alzheimer’s disease and contributes to the cognitive and neuropsychiatric symptoms that characterize it, suggesting that the noradrenergic system would be a good target for pharmacological treatment.

Therefore, the researchers searched for clinical trials published between 1980 and 2021 in which noradrenergic drugs, such as atomoxetine, methylphenidate, and guanfacine, had been used to potentially improve cognitive and/or neuropsychiatric symptoms in people with neurodegenerative diseases.

They included a total of 19 randomized controlled trials focusing on Alzheimer’s disease and mild cognitive impairment, involving 1811 patients: six of these trials were rated as ‘good’ quality, 7 as ‘fair’ and 6 as ‘poor’. .

Results from 10 of these trials, involving 1,300 patients, were pooled for global cognition — orientation/attention, memory, verbal fluency, language, and visuospatial ability. This showed a small but significant positive effect of noradrenergic drugs on global cognition, as measured by the Mini-Mental State Exam or the Alzheimer’s Disease Assessment Scale.

The results of 8 clinical trials, involving 425 patients, were then pooled for behavior and neuropsychiatric symptoms, agitation, and apathy. And this showed a large positive effect of noradrenergic drugs on apathy, even after removing outliers to account for differences in trial design and expected results.

The researchers state that “repurposing of established noradrenergic drugs is very likely to offer an effective treatment in Alzheimer’s disease for general cognition and apathy.”

And they add that “there are compelling reasons to carry out more specific clinical trials of noradrenergic treatments in Alzheimer’s disease”.

However, they warn, several factors must first be taken into account. These include appropriate selection of patient groups and understanding the dose effects of individual drugs and their interactions with other treatments to minimize the disadvantages and maximize the advantages of noradrenergic drugs, they say.