Comparative Effectiveness of ECT vs. KETAMINE Over the Lifespan

This trial will use standard dose of ketamine (0.5mg/kg infusion over 40 min period) in accordance with research studies that have used ketamine as an antidepressant. Treatments will be given two times a week for a maximum of 8 treatments during the acute arm of the study. The investigators will be able to modify dose and number of treatments as indicated clinically per pragmatic clinical trials procedures. Patients will be clinically assessed prior to each treatment to evaluate response and appropriateness of continuation of treatment. Per FDA guidelines a maximum 60mg/dose will be given regardless of body weight.

ECT will be given in a standard manner 3 times a week for 4 weeks. The Initial ECT treatment will be Right Unilateral (RUL) ultra-brief pulse at 6x seizure threshold determined during titration at first visit. If there is not satisfactory improvement with RUL the investigator may change to Bilateral (BL) utilizing brief pulse using 0.5 modified half-age method to determine stimulus intensity. The seizure threshold may increase during the course of treatment and the dose of the electric stimulus may need to be increased incrementally. It is suggested to change to bilateral after three to five RUL treatments if response to treatment is not satisfactory. Treatments will be given three times a week for up to 4 weeks.