Research by scientists in France and Canada suggests that there may be a link between use of benzodiazepine drugs and increased risk of developing Alzheimer’s disease. Benzodiazepines are commonly prescribed to treat anxiety and sleep disturbance. The study is published on 9 September in the British Medical Journal.
The researchers studied the prescription records of nearly 9,000 older people living in the Quebec area of Canada. They used these records to determine the number of people who were diagnosed with Alzheimer’s, as well as the number who had been prescribed benzodiazepines.
Of the people studied, 1796 had a diagnosis of Alzheimer’s and nearly 50% of these had been given benzodiazepines at some point within a five to 10 year window prior to diagnosis. Of the people who were not affected by Alzheimer’s, 40% had also been prescribed the drugs. About 60% of the people studied were still being actively prescribed the drugs at the time of the analysis.
The study found that treatment with benzodiazepines was associated with an increased risk of developing Alzheimer’s. This risk was higher in people who were prescribed benzodiazepines for more than six months. The result was the same after the researchers adjusted their statistical analysis to account for symptoms such as anxiety, depression and sleep disturbances, which may themselves be early indicators of Alzheimer’s or other forms of dementia.
Dr Eric Karran, Director of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“This study shows an apparent link between the use of benzodiazepines and Alzheimer’s disease although it’s hard to know the underlying reason behind the link.
“One limitation of this study is that benzodiazepines treat symptoms such as anxiety and sleep disturbance, which may also be early indicators of Alzheimer’s disease. We know that the processes that lead to Alzheimer’s could start more than a decade before any symptoms show. This study looks at benzodiazepine use five to ten years before diagnosis, and so the disease is likely to have already been present in some people.
“Benzodiazepines have been shown to cause memory problems as part of their side effects and so it is difficult to tease out cause and effect in studies such as this. We need more long-term research to understand this proposed link and what the underlying reasons behind it may be.”