BMJ. 2012 Sep 27;345:e6231. doi: 10.1136/bmj.e6231.
Does using benzodiazepines make it more likely that you will develop dementia? The answer according to this French study is yes. They followed 1063 people in their 70’s over 15 years – 95 began using benzodiazpeines during the follow up and 968 did not use these drugs.
At the end of follow up 30 (32%) of the benzodiazepine group had developed dementia compared to 223 (23%) non-users which translates into a hazard ratio of about 1.6. However the devil here is in the detail - as all clinicians know one of the early signs of dementia can be poor sleep or anxiety for which benzodiazepines are prescribed.
Unfortunately the authors did not control for these problems as possible confounders meaning what they have described is an association, rather than causation, which could be explained by the co-existence of sleep or anxiety problems. A good example of confounding factors in an etiological study. Despite this in my experience there are still good reasons for not prescribing benzodiazepines in the elderly which are the large increased risk of falls and the immediate cognitive confusion they often cause.