I think the $cientologists' choice of lashing out against Ritalin was a smart PR move to hype their anti-drug stance, as, like some one mentioned earlier, many people are wrongy diagnosed with ADD or ADHD.
I work with a lot of teenaged artists, and a great portion of them have been diagnosed with a variety of concentration disorders, despite the fact that they have no problem concentrating on a painting or sculpture or music for hours on end.
To me, it seems as if a lot of wealthy parents with artistic children are unhappy that their children are not as interested schoolwork as with other pursuits, and have managed to sway doctors into perscribing medication they may not need. I wouldn't put blame on the doctors per se, but on the parents who might warp the degree of symptoms that the child has.
I also went to school with a lot of kids who had been labelled early on as ADD, and most of these kids seemed to be not smart, as opposed to inattentive.
It's unfortunate because other drugs they lash out against, such as those for epilepsy and depression, fix well documented chemical imbalances that lack of medication attention could aggravate.
Scientologists seem to concentrate almost entirely on ADHD/ADD and depression to prove that psychiatry does not work. As these are the disorders which are most commonly prescribed and can produce serious side effects. Whenever I try to ask about other mental disorders such as my sister has dispraxia they completely ignore it and again point out Ritalin.
Adderall is really common around 5% of children have ADD/ADHD and it's like candy in college a lot of people use it so they have complete concentration in exams and it's so easy to get hold of.
A lot of artists and people in the creative industry have manic depression because when you get the manic it makes you very creative. A high proportion of people in hollywood have manic depression because of the drive and creativity it gives you when you get the manic. When Stephen Fry asked a load of actors etc. in hollywood if they could start again and not have manic depression would they, only 1 in 20 would not want manic depression.