[A version of this item appears in: Dementia and Elderly Care: the Latest Evidence Newsletter (RWHT), Volume 3 Issue 3, October 2012].
Benzodiazepines (sedatives / sleeping pills prescribed for sleeping problems and anxiety) taken by millions of people appear to be linked to dementia. A French study followed over one thousand elderly adults, free from dementia initially, for 15 years. Those who took benzodiazepines after the first three years of the study were 60% more likely to develop dementia.
This study does not “prove” the causal link between benzodiazepines and dementia, because there may – just hypothetically – be underlying conditions or biological processes which cause people to be prescribed sleeping tablets. Similarly, disturbed sleep could be an initial sign of dementia; although the researchers tried to offset this confounding factor of any pre-symptoms (“prodrome”) of dementia by selecting recruits who did not start taking sleeping tablets until at least the third year of the study.
This research demonstrates an association between the uptake of benzodiazepine use among elderly adults and the risk of developing dementia. Some potential limitations of this study are:
- The actual number of new users of benzodiazepines after the third year of study was small (95), hence limiting the ability to detect significant differences in dementia risk between users and non-users.
- While the researchers attempted to adjust for confounding variables, it is difficult to exclude them all; it is hypothetically possible that the apparent dementia risk may reflect underlying conditions or biological processes in the brain. This study did not investigate other mental health problems such as anxiety. Reverse causation may be at work, such that the early symptoms of dementia cause the use of sleeping pills.
Given the risks, it has been concluded that benzodiazepines should be a “treatment of last resort” for severe acute insomnia or anxiety, and should be taken for no longer than two-to-four weeks.
Widely used sleeping pill ‘increases dementia’ risk. London: NHS Choices, Behind the Headlines, September 28th 2012.
Billioti de Gage, S. Bégaud, B. [and] Bazin, F. [et al] (2012). Benzodiazepine use and risk of dementia: prospective population based study. BMJ. September 27th 2012. 345: e6231.