3 sessions were just scheduled for me, starting tomorrow, for mania. The most common use is for suicidal depression, treatment resistant people with depression or bipolar, during pregnancy instead of medications.

It has been seen as a last resort treatment but that has changed recently because it is so effective. For each antidepressant you try you have a 30% chance that it will work for you. ECT is 80% effective. That is quite a difference.