How effective is ect in helping clinical depression if meds and talk therapy aren't enough?

Still effective!: Ect is still around after 50+ years not because it is easy or popular but because it has a high chance of success in depression. The more acute and severe the episode the more effective it is, in the range of 60-80%, depending on the diagnosis and related conditions. And it's remarkably safe.

It depends.: Ect remains controversial for a variety of reasons. It continues to be a viable treatment in selected situations. The determination of whether to pursue this treatment depends on evaluation by a psychiatrist.

ECT has about: The same success rate that medications do---about 80%.