Genuinely trying to understand ADHD here (I'm really open, have no aggressive intentions, ready to put empathy to use, might have ADHD or other issues myself, I still don't know. I am driven by scientific curiosity). A few questions:

- What are the symptoms? I read here that some argue that they cannot do menial tasks or get up from bed, others get up at 5am regularly or are exceptionally able to do chores. Some can't achieve anything in their life, losing one job after another, others are serial entrepreneurs and feel like having superpowers. I am confused by the broad and (apparent?) conflicting set of symptoms.

- How does the "evolution over time" of ADHD look like? What I mean is: is it a condition that "starts with you" since when you are born, or does it "begin" at some point, like a normal illness? Likewise, can it end? Can you heal from that? Can it be reduced? And in the "in between part", if you were to graph its intensity/presence, would draw a constant(ly high) line? Or are there periods of higher and lower intensity? If so, what is their frequency? And if you were to draw only the segments "controlled for other confounding factors", for example ignoring big impactful events like big successes, personal losses, breakups, particularly happy or particularly bad relationships (even long ones), periods of medication or drugs, turbulent hormonal teen years, periods with second jobs or complete lack of jobs, how would the graph change? I had up and down periods, mostly long downs (even years) and short noisy high frequency ups. Often I was able to identify the causes behind the intensity of my mood (identifying does not imply solving), and I wonder how this time series looks for everybody else, and if and how ADHD people's curves are different from the cluster of "normal" curves.

- What are the tests that are used to assess and quantify it?

- Any scientific study on the effect of various medication on people with ADHD and without? I'm particularly interested in the reported effects for "normal" people in control groups. The effects of some medicines that I often see described sound wonderful: stability, being able to focus, being able to do what is useful (chores, big projects), stopping train of thoughts, etc. Disregarding the fact that, much like with symptoms, it looks like the effects are wildly varying, overall they seem impressively useful, and I ask: are there reasons why anyone would not want improved focus, cognition, productivity and stability? Some of these drugs are indeed famous for being (ab)used by students or even workers, in some parts of the world, to push through stressful times. Why wouldn't and shouldn't everyone have access to those? And, related to this, how does one recognize that they may not be 100% genuine and objective with perceiving and describing their ADHD symptoms to a doctor, but maybe one is exaggerating something unconsciously just to get to those miraculous meds?

- How do you explain (or, better, do you have any paper that explain) the differences in the percentages of diagnosed cases throughout the world (thus, differences over space) and during the last decades (thus, differences time)? Is the incidence naturally different in different countries? Has it naturally changed over time? If so, was that due to a change in other causing factors? Or, more worryingly, did the way of diagnosing it change in time / is different across the world? If so, do you think (or have papers about) the current criteria for diagnosis are accurate and precise (identify the "true value" and with low variance) and uniform? Or is there still work to do? Maybe in 100 years they could have mutated into disgnoses for 10 different more specific disorders, that "our ancestors [we] thought it was just one thing", maybe the disorder won't exist anymore like hysteria evolved from the 1800 to today, or maybe they won't change that much.

- Same question as the above one, but on differences in treatment (over time and across countries). Any anecdotes on people being diagnosed in a rest-of-the-world (non-US) country? Was your experience similar to the ones you read about, from American fellows? Were your symptoms and treatment different? I am particularly interested in hearing more from the rest-of-the-world, being from a non-US country myself. It's hard to understand how much one is in a bubble of American experiences and anecdotes, when reading from the internet. For example, I never even heard in my country the word ADHD. My only experience is from reading about it on the English-speaking part of the Internet. Never heard stories of hyperactive kids taking medicines, or students or adults being prescribed stimulants to push through. I am sure such cases exist, but from my experience these things are just "not in the culture". For almost all the people I know from my country it would be unthinkable to even consider a hyperactive kid to be something to "medically treat". I'm not saying I come from a place where kids with problems are not treated, on the contrary, kids with autism, dyslexia, learning impairments, all sorts of disorders, are followed and given the attention they deserve. I'm just saying that the perceived threshold in the public opinion for what deserves medicines seems to be wildly different than the American one, when it is applied to hyperactivity (or hypoactivity, lack of motivation, etc) and to adults. (I'm from a big country in Europe).

I hope my questions don't come out as provocative. I acknowledge the ignorance in them, because I am ignorant (unknowing) on these topics. And that is the reason I want to find more (and help people like me to understand better).
I appreciate any scientific study, paper, or any article with sources that you can offer. Thank you :)