[SomethingNew2]

Unknown. Some possible reasons:

1. ADHD always existed, is a problem that needs solving for someone to participate in society, and everyone went untreated. Diagnosis has improved.

2. ADHD has increased because of environmental changes such as pollution, food, chemicals, screens, how we raise children, or some other factor.

3. ADHD is a description of a group of people who have different preferences and corporate interests have identified it as a profitable problem and have become dependent on it to hit their revenue targets, so they tell themselves and customers that their kids will not be successful in life without their drugs.

4. Schools and society operate differently now and so opportunities that fit well for people who thrive in more physically active settings have been diminished (more time indoors, less free roaming outside, less physical jobs, etc).

5. A combination of several items above when brought together caused real or perceived increase in ADHD.

6. Something else?

[vouaobrasil]

I also posted this reference below but I doubt it will be seen so:

Williams, Jonathan, and Eric Taylor. "The evolution of hyperactivity, impulsivity and cognitive diversity." Journal of the Royal Society Interface 3.8 (2006): 399-413.

[photochemsyn]

Pharmaceutical companies have made huge profits off this business of drugging children with doctor's approval, why isn't that in your list?

[gyrovagueGeist]

Unless the list has changed since either of us viewed it. It appears to be their number 3.