> I think OP is just saying that 'ADHD' is not that valid of a diagnosis

I understand this in the comment’s expression too, and it’s emphatically wrong.

> benefit from the use of 'medication' (i.e. amphetamines and derivatives, from Adderall to Desoxyn(methamphetamine) to Ritalin), is mostly unrelated to any 'diagnosis'.

You’re incorrect.

> Personally I think all drugs should be legal and people should be able to take whatever they think helps them

I agree, but this has nothing to do with the validity of actual diagnoses of actually treatable conditions.

I think the point is that actual diagonoses are often wrong and potentially harmful, which I agree with. I share a bit of your story, getting diagonised with ADHD benefited me greatly and led me down a path that likely saved my life. At the same time, while many people are helped by the medical system many others aren't and psych drugs are an area where there is a lot of finger waving in how drugs are perscribed.

You got it. The shakiness of this entire thing also shows in how the medication for ADHD is chosen: by trial and error. For real.

Ignoring the fact that basically all drug development outside of the computational stuff is large amounts of trial and error, there is ample evidence that ADHD results from dysfunction of specific neural pathways, and stimulant medication benefits ADHD individuals (more than just "speed helps everyone focus").

> This literature is increasingly contributing to the notion that the pathophysiology of ADHD reflects abnormal interplay among large-scale brain circuits. Moreover, recent studies have begun to illuminate the mechanisms of action of pharmacological treatments.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3876939/

That's how medication for all sorts of things is chosen.