I'm looking for companies that are trying innovative ways to deal with human depression and/or anxiety using more scientific/biochemical methods (rather than meditation / happy thoughts etc)
You can take a look at some startups that sell nootropics. But after going through many natural supplements and prescribed medications, I realized that everyone is different and respond differently. I personally get high blood pressure within days of taking certain nootropics. Certain other ones causing me to be more explosive and agitated. Some natural herbs caused shortness of breath within hour, etc. All these things are very individual so I would not bet on any startup with magic pill to cure everyone. Took me a while to find something that works for me. Maybe there should be startup that guides you through these experiments to find what works for you individually.
I'm looking for something more directed, less trial and error. Form of sensing and cohesive testable theories (less statistical)
But that's sort of is my point, it's all statistical, that's why they have medical trials for years before FDA approves new drugs. We sort of know what is happening in the brain, it's lacking one neurotransmitter or the other and all the drugs/supplements basically either provide it or pretend to be one. Another approach I've seen is to stimulate certain hormones, but again it's individual because some people might have excess of one hormone and lack of the other. Relaxation and meditation is basically natural way to balance certain hormones (reduce cortisol in particular). Or sun exposure gives you vitamin D (which is technically a hormone) and it's been studied to help with depression, but some people need more of it than others etc. I recommend you to pick up a book on nutrition before jumping into this space, one of the easy to read books is Ultramind Solution by Dr Hyman. Hope this helps.