In the JAMA journal of Internal Medicine, (Jan 26th, 2015) researchers have linked higher doses and prolonged use of common over-the-counter drugs to a higher risk of dementia.
The list of OTC drugs includes common hay-fever, insomnia and other anticholinergic-type drugs that block a neurotransmitter called acetylcholine.
Professor Dr. Shelly Gray and colleagues from the University of Washington followed the health of 3,434 people aged 65 and older who had no signs of dementia at the start of the study. The researchers found the increased risk appeared when people took drugs every day for three years or more.
Drugs in the study included tricyclic antidepressants for treating depression, and antihistamines used to treat hay-fever and allergies.