Drugs to treat attention deficit hyperactivity disorder (ADHD) have provided “good evidence” that they could also help some symptoms of Alzheimer’s disease, such as cognitive symptoms and apathy.
A British study published in the Journal of Neurology Neurosurgery & Psychiatry focuses on noradrenergic drugs, including antidepressants and compounds that treat ADHD.
These drugs target the neurotransmitter norepinephrine, also called norepinephrine, which is released by a network of specialized neurons and is essential for many cognitive processes, such as attention, learning, memory, or preparing for action.
In a very early phase of Alzheimer’s, noradrenergic alteration occurs, which contributes to the cognitive and neuropsychiatric symptoms that characterize the disease, suggesting that the noradrenergic system would be a good target for pharmacological treatment.
The Imperial College London-led team reviewed some twenty clinical trials between 1980 and 2021 in which noradrenergic drugs were used to potentially improve cognitive and/or neuropsychiatric symptoms in people with neurodegenerative diseases.
Results from ten of these trials were pooled for global cognition: orientation/attention, memory, verbal fluency, language, and visuospatial ability.
“This demonstrated a small but significant positive effect of noradrenergic drugs on general cognition,” measured on the Adas scale, which is used to assess the severity of cognitive impairment in Alzheimer’s, the publication notes.
Results from eight trials were pooled for behavioral and neuropsychiatric symptoms, agitation and apathy, and showed a “large positive effect” of noradrenergic drugs on apathy.
“It is very likely that the retrofitting of established noradrenergic drugs will offer an effective treatment in Alzheimer’s disease for general cognition and apathy,” according to the team, which considers that “there are compelling reasons” to conduct more specific clinical trials.
But he cautions that several factors must be taken into account, such as appropriate selection of certain patient groups and understanding the dose effects of individual drugs and their interactions with other treatments. (YO)