A new Open Access study published in the prestigious BMJ journal finds indication that use of benzodiazepines, widely prescribed drugs for treatment of anxiety and insomnia, is associated with an increased risk of developing Alzheimer’s disease, particularly for long-term users.

These drugs, medically referred to as benzodiazepine receptor agonists, work by increasing the effectiveness of a neurotransmitter called gama-amniobutryic acid (GABA) that impedes sending alert fullness signals to other nerve cells. This action has the complimentary effects of reducing anxiety, increased sedation and muscle relaxation, and benzodiazepines are commonly prescribed to treat general anxiety, panic attacks, insomnia, seizures (including status epilepticus), muscle spasms (such as in tetanus cases), restless legs syndrome, alcohol withdrawal, opiate withdrawal syndrome, withdrawal from benzodiazepines themselves, and Ménière’s disease. They may also be used for sedation in certain medical procedures such as endoscopies to reduce tension and anxiety, and impart pain tolerance, and in some surgical procedures to induce amnesia or to reduce anesthesia dose requirements or as the sole agent when IV anesthesia is not available or is contraindicated.

However, a Wikipedia entry notes that concerns about long-term effects of benzodiazepines have been raised since at least 1980, and remain to be fully answered, and cites a 2006 metanalysis of the literature on use of benzodiazepine and nonbenzodiazepine hypnotics, concluding that more research is needed to evaluate long-term effects of hypnotic drugs.
The majority of benzodiazepine problems have been related to long-term as opposed to short-term use, and the article says there is a growing body of evidence of harm resulting form long-term use (ie: longer than 2-4 weeks to three months depending on whose definition of “long term”) of benzodiazepines, especially at higher doses.

 The article says long-term effects of benzodiazepine use are very similar to long-term effects of alcohol abuse (with the exception of organ toxicity with the latter) and of other sedative-hypnotics, and that withdrawal effects and dependence are almost identical, citing a 1987 report by the Royal College of Psychiatrists in Great Britain determining that any benefits of long-term use of benzodiazepines are likely to be far outweighed by the risks of long-term use. Nevertheless, benzodiazepines continue to be widely prescribed, and use of these drugs for treatment of anxiety has been found to significantly increase healthcare costs due to accidents and other adverse effects associated with their long-term use.
 When they first came on the market in 1961, benzodiazepines were initially regarded as safe and beneficial drugs. For a time, Valium (diazepam) was reportedly the highest-selling drug worldwide, and The New York Times Magazine’s Robin Marantz Henig reports that Xanax, the leading successor product to Valium, outsells every other psychiatric drug on the market (48.7 million prescriptions in 2011), with Valium itself still selling briskly to the tune of 14.7 million prescriptions written in 2011.

An astonishingly prolific range of benzodiazepine drugs are available in many forms, including tablet, capsule and liquid as well as injectable types. The most common variants include: Klonopin (clonazepam), Xanax (alprazolam), Librium (chlordiazepoxide),Valium (diazepam), Ativan (lorazepam), Doral (quazepam), Halcion (triazolam), and Rohypnol (flunitrazepam).

Adverse effects of benzodiazepines have been associated with anterograde amnesia and confusion (especially pronounced in higher doses) and sedation, with the elderly in particular being more prone to adverse effects of these drugs, such as confusion, amnesia, ataxia, and hangover effects, and falls.