Ergot, the "jerks," and revivals.

Epidemics of epilepsy, a form of mass hysteria, were known in Eastern and Western cultures in the 17th and 18th centuries. A unique situation in the United States during the 19th centurey was the frontier religious movement, the setting in which the "jerks" occurred. The "falling exercise," "dancing exercise," "barking exercise," "laughing exercise," and the "running exercise" centered around the excitement involved in the religious revival. During some exercises, people saw "visions," and exhibited bizarre behavior and sudden jerking motions. During the summers of 1801-1803 on the Kentucky frontier, some pioneers who attended the religious revival camp meetings had convulsions, hallucinations, tremors, jerks, compulsive dancing and "epileptic trances." Although these have been assumed to be psychological in origin, the epidemiology of the symptoms may correlate with the diagnosis of ergotism. Those affected were usually children and young adults. Symptoms of ergotism include giddiness, fatigue, depression, formications, muscle twitching, tonic spasms, convulsions, delirium, and loss of speech.