Most drugs prescribed for the treatment of anxiety are known as anxiolytic, meaning that they inhibit anxiety. This broad type of medications includes benzodiazepines and also some of the serotonergic antidepressants, although some of the latter can actually increase anxiety when patients first start taking them. As such, they have a temporary anxiogenic effect.

The treatment of anxiety and related disorders has a history that stretches back at least as far as the 1500s, when healers diagnosed it as “hysteria.” During most of this history, however, the efforts of physicians and researchers were largely focused on trying to understand its operation and origins, and in some cases suggesting behavioral approaches that might decrease the patient’s suffering. Throughout this early history, the only substance that could be ...