Benzodiazepine receptor agonists attach to a site on the γ-aminobutyric acid type A receptor, but when they're used for an extended period of time, usually defined as anything more than 1 to 2 weeks at the most, the receptor physically changes, eliminating the drug's potential for sedation and anxiety relief, or any other benefit, and often leaving in its wake what the glossy brochures chirpily dismiss as " .... persistent amnestic effects...", along with tardive dyskinesias, recurring panic attacks, pretty severe and undefeatable insomnia, diplopias, severe cognitive impairments, and a host of other unwelcome guests.
Although they are beneficial for short-term improvement in sleep onset latency and duration, along with anxiety, social phobias, etc, they also have substantial associated side effects, including problems with dependence and withdrawal, and some of these issues can be very long-lasting.
They can be especially destructive to older patients, whose brains and central nervous systems aren't as resilient as they might have been when they were younger.