Benzodiazepines, drugs which are used to treat insomnia and anxiety, can increase the patient's risk to develop Alzheimer's disease when taken on longer-term. Older patients who have relied on the drugs are mostly found in developed countries.

The drug is retailed under various names such as Klonopin, Seresta, Dalmane, Versed, Mogadon, Restoril, Halcion, Ativan, Valium and Xanax. All have been widely used to treat agitation, insomnia and anxiety which can be the early signs of Alzheimer's disease among the elderly.

Researchers of the study compared the pattern of using benzodiazepine by elderly people with 1,796 that have been studied to be diagnosed with Alzheimer's while the other 7,184 had no diagnosis of the disease. The study cannot be used solely in establishing that an increased use of the drugs can cause Alzheimer's disease. However, it does give the researchers a stronger basis to suspect on the drug's connection to Alzheimer's.

The study, which was conducted in Quebec for a period of six years, found out that past use of benzodiazepines is linked with a fifty-one percent increase in the risk of Alzheimer's. The link is also found to be stronger when a patient has been exposed to the drugs in a longer period or has been using long-acting versions of it.

According to Professor Malaz Boustani of the Indiana University Centre for Aging Research and Professor Kristine Yaffe of the University of California at San Francisco, the American Geriatrics Society placed benzodiazepines in 2012 in their list of drugs that should not be prescribed to older people. The reason is the drug's side effects content in the functioning of the brain. However, almost 50 percent of older adults continue to use the drugs.

"This work provides yet another reason to avoid prescription of benzodiazepines for anything other than very short term relief of insomnia or anxiety," said Dr. Liz Coulthard who works as a Consultant Senior Lecturer in Dementia Neurology at University of Bristol.

Coulthard adds that while the use of benzodiazepine has been associated with falls, car accidents and short term cognitive impairments, the study further hints that the drugs may increase the risk of developing Alzheimer's disease.

Boustani and Yaffe suggest that it may be necessary to conduct a formal monitoring system in order to predict the long-term consequences of the drugs on the patient's brain health.

Physicians are also encouraged to carefully balance between the benefits and risks involved when prescribing or renewing a treatment with benzodiazepines in elderly patients.