London: A trial of 41 people over 60 years with mild cognitive impairment, a precursor to full-blown Alzheimer`s, found that the rate of mental decline was lower in the half given 150 mg of lithium daily, compared to those given a simulated medical intervention.
While all participants showed a decline in memory function and attention tasks over the years, the rate of decline among those on lithium was significantly less.
Levels of a biomarker for Alzheimer`s disease called phospho-tau concentrations also rose more slowly in those on lithium, said a research result published in the British Journal of Psychiatry.
Psychiatrists believe this is because it "may hamper mechanisms that lead to the formation of amyloid plaques and neurofibrillary tangles", microscopic brain structures linked to the most common form of dementia, the Telegraph reports.
Orestes Forlenza, who led the research, said: "This study supports the idea that giving lithium to a person who is at risk of Alzheimer`s disease may have a protective effect, and slow down the progression of memory loss to dementia."
Professor Allan Young, psychiatrist from Imperial College London, described the study as "encouraging" - and particularly interesting because no pharmaceutical company has a patent on lithium, meaning it is very cheap to prescribe.
He added: "This trial adds to the increasing evidence that lithium may have beneficial effects on the brain and begs to be replicated in further randomised trials."