Stimulants help people focus, not just people with ADHD. This is a known fact and this is why people with ADHD benefit from stimulant use. There is no "paradoxical" effect at all - stimulants (in small doses) help many people focus and concentrate (note the mighty coder and his one true love: caffeine).

In any case, there is at least one drug for ADHD that doesn't use stimulants (Strattera) though I know little of it (check for more information and some creepy looking "normal" kids). Anti-depressants and neuroleptics may also be used (although neuroleptics can cause movement disorders so they are generally the last choice).

Regarding the so-called addictiveness of Ritalin and its ilk, as well as speculation it serves as a gateway drug, I will just quote an article by Michael Fumento:

Further, he says, "There's no evidence anywhere in literature of Ritalin's addictiveness when taken as prescribed." As to the Schedule II listing, again this is because of the potential for it to fall into the hands of abusers, not because of its effects on persons for whom it is prescribed. Ritalin and the other anti-ADHD drugs, says Barkley, "are the safest drugs in all of psychiatry." (And they may be getting even safer: A new medicine just released called Strattera represents the first true non-stimulant ADHD treatment.) Indeed, a study just released in the journal Pediatrics found that children who take Ritalin or other stimulants to control ADHD cut their risk of future substance abuse by 50 percent compared with untreated ADHD children. The lead author speculated that "by treating ADHD you're reducing the demoralization that accompanies this disorder, and you're improving the academic functioning and well-being of adolescents and young adults during the critical times when substance abuse starts."

Some studies have concluded that stimulants may be over-prescribed in some areas but under-prescribed in others (ie/ low income areas). For brevity I won't cite them individually, but feel free to read my sources. It is easy to misdiagnose this condition (for example, a learning disability, petit mal seizures, high intelligence, hearing problems, anxiety, depression, abnormal living conditions such as living with an alcoholic, and other environmental and factors can lead to a misdiagnosis) so diagnosis generally takes a minimum of six months. As in any other condition, misdiagnosis can occur, but it is hardly epidemic, despite what the media may tell you. Unfortunately we get articles and shows such as "Kiddie Cocaine" from CBS (yeah, that sounds even-handed). The NIMH, in contrast, states:

Recent reports (1998 and 1999) found little evidence of overdiagnosis of ADHD or overprescription of stimulant medications.

This relates to the idea that ADHD is a "made up condition" or "bad parenting in action." Unfortunately, it is a very real condition that has little or nothing to do with environment. For example, ADHD children often have siblings that do not have ADHD and the only noted commonality of ADHD home environments is overintrusiveness and overcontrolling of the parents (which is reduced once the child receives treatment) (Carlson et al., 1995 and Barkley et al., 1985).

The physical developmental effects of psychostimulants in children have been the subject of a few studies. They concluded that there are no long term effects to height and weight (Klein & Mannuzza, 1988; Vincent et al., 1990). It is recommended that the height and weight of children on stimulants be monitored as a precautionary measure. Of course, the child's psychosocial development is greatly aided by using psychostimulants. At this time, I am unable to find information regarding any other potential developmental problems associated with stimulants (although stimulant abuse has been shown to cause problems similar to ADHD) but I will update this write-up if I find any (positive or negative).

NIMH - Attention Deficit Hyperactivity Disorder. . National Institute of Mental Health. March 10, 2003
Mental Health: A Report of the Surgeon General - Chapter 3. . US Public Health Service. March 10, 2003
Clinical Practice Guideline Diagnosis and Evaluation of the Child With Attention-Deficit-Hyperactivity Disorder (AC0002). . American Academy of Pediatrics. March 10, 2003
Trick Question: A Liberal Hoax Turns Out to Be True . . Michael Fumento. March 10, 2003 (I have absolutely no respect for his political views, but his science writing is generally even-handed and he doesn't hide his bias)
Forgot the hardlinks...