*Edit: I checked some of the stuff more out in detail. While some concepts on this are valid and backed up by sience, others like RSD are not. Use this as a springboard for learning, not as a valid source in itself. Yes it says so in the corner already. But spelling it out might help.
People are more complicated then a diagram from the internet. Never forget that.
I was formally diagnosed with ADHD in February this year, but due to suspicions I spent a long time (with the help of my family) trying different supplements or diet related things, etc. The thing we settled on is a supplement of Citicoline (which at least where I am is available at most pharmacies/chemists). It took a couple weeks to settle in, but for me it was a night and day difference in terms of emotional/mental stability. Even now I'm on a proper Ritalin regime, I still find the Citicoline helps with that part. To clarify, I didn't find it explicitly helped with focusing, but that mental and especially emotional stability was life changing, and helped me on the road to getting more formal treatment.