I used to think I was depressed because of an hormonal imbalance, a shit diet, neet life, bad habits, and what not, so I started strength training 3-4 times a week, and cardio 2-3 times a week, caloric restriction, loads of veggies, no carbs (keto). For the first time in my life I feel balanced and fit, and don't need caffeine to get through my day, but at the same time I've come to the realisation that my depression isn't just chemical, because I still feel empty, and nothing will fill that emptiness. I feel that life is just trying to trick your brain into thinking that everything you do is new and interesting, even though it's not. The cruel reality of life is that it's as pointless, in essence, as simpler inert matter.
My conclussion is that people are nothing more than drug addicts, be it with a natural drug (oxytocin, endorphins, adrenaline) or from artificial drugs. Always waiting for the next shot.