As HB says, ECT is usually used in med resistant depression.

Ketamine has shown promise to have a fast acting effect on depression but I don't think that the effect lasts very long. I don't think its widely used yet and I would be very cautious using it in conjunction with a BP diagnosis because it is a dissociative anaesthetic which can cause "trip like" hallucinations. I know my hubby used it as an anaesthetic for a BP patient once and sent the poor girl into a dysphoric hallucination - not pleasant.

Finding the right antidepressant is unfortunately a slow and painful process as you need to try the different ADs for about a month at each dose before you try the next one. Hopefully you have a good doctor who will work with you to find a good combination.

Its really important to have your mania resolved or you will continue to experience depression cos manias tend to end with a depressive episode. And anything that acts as an AD can send you into mania so that needs to be monitored to make sure you are not having AD induced manias.