Mainly used to treat anxiety and insomnia, benzodiazepines are widely used in developed countries, particularly among the elderly. Because of strong withdrawal symptoms, and because long-term effectiveness of the benzodiazepines remains unproved, international guidelines recommend only short-term use of the drugs.
The study found that benzodiazepine use for 3 months or more was associated with an increased risk of Alzheimer's disease of up to 51%. The longer the exposure to benzodiazepines, the greater the risk of Alzheimer's. Long-acting benzodiazepines were also found to increase risk more than short-acting benzodiazepines.
The researchers report that adjusting for symptoms that might suggest dementia onset - such as anxiety, depression or sleep disorders - "did not meaningfully alter the results."