Some adults who have ADHD view it not as a disability, but an asset. Bright and creative, they would never dream of "blunting" their personality with medication.

And, in fact, some studies show that ADHD's "symptoms" may have evolved as survival mechanisms in our hunter-gatherer past.

A University of Minnesota study, funded by the National Science Foundation (http://www.nsf.gov/), in 2004 linked impulsivity - a hallmark of ADHD - to evolution. Researchers hypothesized that in the wild, snatching up small bits of food instead of waiting for a more substantial meal meant better long term rewards - such as not starving. They thought that phenomenon could explain why today's humans are so often "immediate gratification" oriented when it comes to sex, money, euphoria and food, rather than investing in a longer range horizon that could result in a greater reward later on.

In experiments with blue jays, the birds could not be trained to wait for bigger food rewards, even with a thousand repetitions. Researchers theorized that evolution had hardwired the birds to forage, snatch up the small, immediate rewards, then return to foraging - the end result being more food than if they'd passed over the immediate, in hopes of something bigger.

In the past, human "foragers," too, may have benefited from snatching up immediate "rewards" - while in today's world, an impulsive decision in the choice of mate, education and investment can have disastrous consequences.

Still, there are multiple of examples of successful people thought to have ADHD whose propensity for quick decision has been a plus. Examples include billionaire Malcolm Forbes; steel baron Andrew Carnegie; British Prime Minister Winston Churchill; physicist Steven ("A Brief History of Time") Hawkins; publishing magnate William Randolph Hearst (in one study, 85 percent of journalists surveyed had AD(H)D); President John F. Kennedy, his brother Robert, and son, John Jr.; Academy Award winning movie producer Steven Spielberg and many others.

It's believed Albert Einstein, Benjamin Franklin, Sir Isaac Newton and other "inventive" thinkers are also among those who had, or have, ADHD. (Source: Learning Disabilities Association of Nova Scotia, www.ldans.nsnet.org.)

Still, there's no question that impulsivity has its down side. When the National Institute on Drug Abuse (www.nida.nih.gov) funds studies on impulsiveness, many studies find that impulsivity seems to play a role in drug addiction. And when psychologists evaluate children who are good at waiting for a reward, such kids appear to do better in life. The Minnesota researchers concluded that the reason it's so hard for many to accept delays is because we evolved as foragers, who, in earlier times, suffered no penalty for impulsively snatching up available resources as we found them.