Scientists from Canada and France published in the May 2015 issue of The Lancet that the use of benzodiazopines was linked to an increased risk of developing Alzheimer's disease. They reviewed health insurance records of about 1800 patients who were recently diagnosed with Alzheimer's disease. They then determined those patients who had been on benzos 5-10 years prior to their diagnosis and compared them to 7100 healthy controls who did not have Alzheimer's disease.
They found a 50% increase in the risk of developing Alzheimer's disease in those people who were taking benzos for three months and a doubling of the risk for those who took benzos for 6 months. There was a dose dependent association as well as the lenght of time these patients were treated.

