I don't believe a signal thing about this.
Depression detected through brainwaves - out of this world amazing, cutting edge breakthrough.
Knowing what sort of depression - out of this world amazing, cutting edge breakthrough.
Knowing how to treat it - out of this world amazing, cutting edge breakthrough.
Using "AI" - out of this world amazing, cutting edge breakthrough.
Each of these are billion $ breakthroughs.
They're not claiming to detect depression, I don't think there is "sorts" of depression. They're measuring a change in symptoms to evaluate a medicines usefulness.
The headline is misleading but I do feel their work has merit. Years ago I had an isolated Major Depressive Episode. It's clear to me that during that period of time there was something different about my brain.
If SSRIs primary function is increasing indifference, a personality inventory on sadness will still turn up as improved if the patient cares less about it. Saying that this is a treatment of the symptom is confounding effects and could pave the way for decades of poor science. And that's assuming that the data is interpretable in the way that they think it is and that it's not more akin to fMRIs.