The best treatment for my own ADHD, depression and anxiety is living a healthy lifestyle, across the board, full stop.

It means regular exercise, 6 hours of cardio a week, eating healthy, meditating, spending time in the sun, etc. etc. (And anti-depressants/therapy, which play an important role too.)

Of course, it's too much to tell someone struggling to do all those things, but if you can work towards that, I strongly recommend it. I've had to declare war on my depression and ADHD because I can't afford to have it in my life anymore.

At some point perhaps the science will catch up and explain precisely how these things help, but until then, I feel like you have to take the ancient approach of observing people who have things figured out and emulating them. (And I say this as someone who is very much pro-science.)

What was your diet like when you were taking them? It's been observed in some studies that delivered mixed results that responders had better diets (i.e. more bacteria friendly components in the diet such as indigestible carbs from vegetables/legumes/fruit etc) whereas non-responders had weaker diets in terms of providing the gut microbes nutrients.