My graduate school research was associated with a very active bipolar disorders research group. Whenever ECT came up in casual discussion, nearly all the psychiatrists said they would personally choose ECT over medication.
I can't say I understand the diseases or symptoms that represents, but there's significant literature available for the efficacy of ECTs in relieving over-active and/or over-connected brains. Hell, one of the horror stories is in itself a success case—Sylvia Plath's The Bell Jar.
