When we last reviewed neurostimulation devices 3 years ago, we concluded that there was some promise—but more sizzle than beef. Now there are more devices and more data. But is there more beef? Maybe.

In this article, the focus will be restricted to the following non-invasive technologies: transcranial magnetic stimulation, or TMS; magnetic seizure therapy (MST); transcutaneous vagal nerve stimulation (t-VNS); and transcranial direct current stimulation (tDCS).