I was wondering is ect an effective treatment for depression?

Very effective: Ect (electroconvulsive therapy, commonly called "shock treatment") is very effective for severe depression. It's usually given 3 times weekly for a few weeks, not just once. It's reserved for severe cases unresponsive to other treatment, as ECT requires anesthesia ; other drugs to manage the induced seizure, ; can cause memory loss (amnesia) ; other serious side-effects. Best as a last resort.