Tranquilizers are drugs that reduce feelings of anxiety and tension. Since the 1960s, benzodiazepines have been popular as prescription medications for the treatment of anxiety. Benzodiazepines are also effective at treating insomnia, an inability to fall asleep or stay asleep, and other sleep disorders. In the 1990s some health-care professionals as well as the public became concerned about the overuse of these drugs and possible complications.

Benzodiazepines that lessen the symptoms of anxiety include chlordiazepoxide (Librium), diazepam (Valium), lorazepam (Ativan), oxazepam (Serenid; Serax), clonazepam (Klonopin), and alprazolam (Xanax). Benzodiazepines that cause a person to fall asleep and stay asleep include short-acting drugs such as triazolam (Halcion), medium-acting drugs such as temazepam (Restoril), and long-acting drugs such as flurazepam (Dalmane) and nitrazepam (Mogadon).