karen miotto: the earlier you start smoking, the harder it is to stop smoking. basic scientists believe that that may actually be due to altered brain chemistry, that there may be a window of vulnerability in children and adolescents that interferes with development by smoking earlier. many people will die an early preventable death because of a decision made as a child. only 11% of adult smokers started the habit after age 18. risk factors that parents should look for... are they are suffering from other emotional problems, conduct problems, poor school performance? teenagers who are susceptible to peer pressure or are rebellious may also be more likely to start smoking, and once they start, it's difficult to stop. nicotine is a powerfully addictive drug. if you ask people about their first smoking experiences, most people will tell you that they were ghastly. very unpleasant. they made them dizzy. it made them nauseous. they had these nasty reactions to this stuff which probably is our body's way of telling us, "stop now! enough already!" but we don't, and peo