What's needed in my opinion is total paradigm change. Depression as a "disease" holds no water. It's a symptom. The question is of what? Many possibilities it seems. Here's how I see various interventions:

- Rx psych drugs: Tools for symptom suppression and for altering mood, nothing more, and with possibility of long term damage and worsening symptoms.

- talk therapy: When you strip away the pseudoscientific methods and approaches, seems what could help is just having a connection with another human. I don't see this as treatment, Comes with huge risks and problems with transparency, ethics, lack of evidence.

These are the things that seem essential or critical:
- healthy relationships
- exercise, proper sunlight and circadian rhythm habits, direct contact with nature
- good diet, good gut health
- good sleep
- addressing nutrient deficiencies, thyroid and adrenal issues
- amino acids/neurotransmitter precursors (as mentioned by others): Similar to the drug model and a little sketchy I think, but seemingly with substances that are closer to what the body recognizes as nutrition, less toxic, less dangerous
- treating chronic viral and bacterial and fungal infections
- reducing body burden of environmental toxins: mercury, aluminum, mold, EMFs, plastics, etc
- spiritual, existential stuff

This is just my take...