1. A main purpose has been to build a "control" series of 567 consecutive manic-depressive cases under hospital treatment before the advent of shock methods (1925-34). Recovery rates are found to be 59% on discharge, 55% after one year, and 64½% after 5 years.2. A comparison with 563 consecutive cases under the same hospital treatment with EST available (1940-46) and used in about ¾ of these cases suffers because less than one-half could be followed for 5 (war) years. However, the recovery rates are 72% on discharge, 71% after one year, and 66% after 5 years.3. In the control group the average stay in the Pennsylvania Hospital for recovered cases was 4.5 months; in the later group recovered patients (¾ of them treated with EST) had an average stay of 2.3 months.4. Over half of all cases who recovered in both series remained well for 5 years or more. The EST series showed more breakdowns in those who could be followed.5. The usefulness of electric shock therapy in shortening attacks is clear.6. The importance of emphasizing "shortening the attack" is shown by a look at those patients listed as in fair condition with a minor defect—or much improved. There are more of these in the control series and there 135 cases would add nearly 24% to the proportion of good results on discharge. In 1940-46 there were 97 cases or only 17% to be added. But again in this group which might be called "much improved" the controls averaged 4.8 months' hospital stay while the advent of EST reduced the time to 2.3 months.Abstract Teaser