“Today, ECT is administered to an estimated 100,000 people a year, primarily in general hospital psychiatric units and in psychiatric hospitals. It is generally used in treating patients with severe depression, acute mania, and certain schizophrenic syndromes. ECT is also used with some suicidal patients, who cannot wait for antidepressant medication to take effect… This treatment is usually repeated three times a week for approximately one month. The number of treatments varies from six to twelve.”
Might explain why Mom was hospitalized for a month each time.