Consider the following scenario. The three most commonly prescribed drugs for attention deficit/hyperactive disorder are all powerful stimulants: ritalin is methylphenidate hydrochloride, dexedrine is dextroamphetamine, and adderall, which is rapidly becoming the most popular, is a time-release mixture of four drugs, dextroamphetamine saccharate, amphetamine aspartate, amphetamine sulfate, and dextroamphetamine sulfate. Occasionally, pure methamphetamine is prescribed, under the trade name desoxyn. All of these drugs have a thriving black market trade associated with their recreational use; of the three commonly prescribed pills, adderall is considered the most desirable and ritalin the least.
Now, the use of stimulants to control a disorder whose main symptoms are hyperactivity seems a bit odd at first glance. The standard medical explanation for this is that the drugs tend to have a paradoxical effect in patients suffering from ADD/ADHD. In other words, they do the exact opposite of what they do to everybody else.
Consider a few more facts. All of these substances take effect a few hours at latest after they are consumed. All of them are quite addictive. In all cases, the medical literature states that full effects from the course of treatment may not be seen for as long as six weeks. Let's break out Occam's Razor.
Now, I could, of course, be totally wrong, but it seems to me that what may be having the "therapeutic" effect are not the actual stimulants, but the body's eventual dependence on the stimulants. Now, I'm not Nancy Reagan (thank God), so I'm not saying that drug dependence is automatically and without qualification morally wrong. But if you consider the fact that many therapists believe that ADD and ADHD are being misdiagnosed far more often than they actually occur (there are currently four million children in America on Ritalin, some as young as 2), the waters get cloudier.
Something awful may be going on. A generation is being raised on medication, for what in many cases may be nothing more than their parents and teachers not wanting to deal with them, simultaneous with a spectacularly ineffective Great Big War on Drugs. The developmental effects of addicting toddlers to stimulants are largely unknown, but it's not exactly a reach to say that they're unlikely to be good.
Historians speculate that one of the reasons that the Roman Empire fell is that the Roman custom of sweetening wine with lead caused collective brain-damage to everybody rich enough to drink wine. It's possible we may be doing the same thing to ourselves.
Note: this is my scholarly, intellectual-style take on this issue. For some good old fashioned fire-breathin' and doom-sayin', see mint-flavored liquid prozac.