ADHD drugs might also treat Alzheimer's disease

There is "good evidence" that drugs to treat attention deficit hyperactivity disorder (ADHD) might also successfully treat key aspects of Alzheimer's disease, finds a pooled data analysis of the available research, published online in the Journal of Neurology Neurosurgery & Psychiatry.

Noradrenergic disruption occurs early in Alzheimer's disease and contributes to the cognitive and neuropsychiatric symptoms that characterise the condition, suggesting that the noradrenergic system would be a good target for drug treatment.

The researchers therefore looked 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 disease.

They included a total of 19 randomised controlled trials focusing on Alzheimer's disease and mild cognitive impairment, involving 1811 patients: six of these trials were judged to be 'good' quality, seven as 'fair', and six as 'poor'.  The results of 10 of these trials, involving 1300 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 overall 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 behaviour 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 intended outcomes.

Repurposing of established noradrenergic drugs is most likely to offer effective treatment in Alzheimer's disease for general cognition and apathy, ended the researchers.

Reference: "Cognitive and neuropsychiatric effects of noradrenergic treatment in Alzheimer's disease: systematic review and meta-analysis" BMJ- Journal of Neurology, Neurosurgery & Psychiatry. DOI:10.1136/jnnp-2022-329136