Patients over 65 years of age who take the popular insomnia and anxiety drug, benzodiazepine, have a 50% higher risk of developing dementia during the following 15 years compared to people of the same age who never took the medication, researchers reported in the BMJ (British Medical Journal).

The authors say that their findings indicate that widespread indiscriminate use of benzodiazepine should be cautioned against, given the extent to which this type of medication is prescribed. Benzodiazepines have a number of potential adverse effects.

Benzodiazepine is sold extensively to elderly patients throughout the world. 30% of people over 65 years of age in France are prescribed benzodiazepines, 20% in Canada and Spain, and 15% in Australia. Benzodiazepine usage in the USA and the UK as a percentage of seniors is lower than in the other countries mentioned; however, the total number of users is still high, given the size of the US population. Guidelines suggest that benzodiazepines should only be used for a few weeks.

The authors explained that some previous studies had pointed towards a possible association between benzodiazepine use and dementia risk. However, many of them were non-conclusive.

Sophie Billioti de Gage, a PhD student from the University of Bordeaux Segalen in Bordeaux, France, and team set out to determine what impact benzodiazepines might have on dementia risk. They performed a study involving 1,063 elderly males and females with an average age of 78 years. They were all French, they lived in France and none of them had any signs or symptoms of dementia at the start. The study, which began in 1987, continued with regular follow-ups for a period of 20 years.

During the first five years of follow-up, the scientists tried to identify what factors led to people starting on benzodiazepine in the first place. They evaluated the link between new use of benzodiazepine and dementia onset. They also wanted to find out what the association might be between further benzodiazepine usage during the follow-up period and subsequent dementia risk. They made adjustments for several factors which might affect dementia risk, such as age, gender, wine consumption, diabetes status, blood pressure readings, cognitive declines, symptoms of depression, marital status, and educational level.

Out of the 1,063 participants, 95 were prescribed benzodiazepine during the study. During the follow-up period there were 253 cases of confirmed dementia, of whom 30 were on benzodiazepines and 224 were not. The researchers worked out that people who started on benzodiazepine had a shorter dementia-free survival period.

They found that the risk of developing dementia during the 20 years that followed were:

  • 4.8 per 100 person years among those on benzodiazepine
  • 3.2 per 100 person years among those not on benzodiazepine

The researchers say that even though benzodiazepine is effective for the treatment of insomnia and anxiety, there is growing evidence that it is linked to a number of adverse outcomes among seniors, including serious falls and fractures caused by falls (however, a 2007 Harvard study found no link between benzodiazepine usage and hip fractures). Now there is another adverse outcome – the possibility of developing dementia.

If their data is backed up with further studies regarding benzodiazepine usage and dementia risk among elderly patients, this “would constitute a substantial public health concern”, the authors believe.

Not only should further studies be conducted to confirm their findings, but also mechanisms need to be examined to understand why this association exists, the researchers concluded.

Benzodiazepines are a type of drug known as tranquilizers, and more specifically minor tranquilizers. Familiar names include Valium (diazepam), Ativan (lorazepam), Klonopin (clonazepam) and Xanax (alprazolam). In the USA, they are one of the most widely prescribed medications, especially among elderly patients.

Benzodiazepines may be prescribed for the following medical conditions:

  • Insomnia
  • Anxiety
  • Alcohol withdrawal
  • Given before being administered an anesthetic, before a surgical procedure
  • Muscle relaxation
  • Seizure control

Benzodiazepine abuse is a serious public health concern.

Written by Christian Nordqvist