context: ADHD may last into adulthood about a third to half the time, and some studies have shown that children with ADHD may be more likely than the general population to develop alcohol and substance abuse problems when they get older. Several studies have shown a strong connection between ADHD, drug abuse, and alcoholism. ADHD is five to 10 times more common among adult alcoholics than it is in people without the condition. Among adults being treated for alcohol and substance abuse, the rate of ADHD is about 25%. It is also more common for children with ADHD to start abusing alcohol during their teenage years. In one study, 14% of children ages 15-17 with ADHD had problems with alcohol abuse or dependence as adults, compared to peers without ADHD. Another study found that at a mean age of 14.9 years, 40% of children with ADHD began using alcohol, compared to 22% of children without an ADHD diagnosis -- a strong predictor of alcohol and substance abuse in adulthood. Young adults (mean age of 25), on the other hand, were just as likely to use alcohol whether or not they had an ADHD diagnosis, but those with ADHD were likelier to use alcohol excessively . Researchers have also found links between ADHD and the use of marijuana and other recreational drugs, particularly in people who also have other psychological disorders (such as obsessive-compulsive disorder). What's more, people with ADHD typically start having problems with drugs and alcohol at an earlier age than people without the condition. People with ADHD tend to be more impulsive and likely to have behavior problems, both of which can contribute to drug and alcohol abuse, researchers say. Also, both ADHD and alcoholism tend to run in families. A child with ADHD who has a parent with alcoholism is more likely to also develop an alcohol abuse problem. Researchers have pointed to common genes shared between ADHD and alcoholism. Parents sometimes worry whether the stimulant drugs their children are taking to treat ADHD (such as Ritalin and Adderall) are themselves addictive. Stimulant medications work by raising levels of a chemical messenger called dopamine in the brain, which helps improve focus and attention -- skills that people with ADHD often find difficult to master. Dopamine also affects emotion and the feeling of pleasure, creating a "high" that makes people want more. Because cocaine and other street drugs also raise dopamine levels, there has been concern that ADHD stimulants might be similarly addictive. Ritalin's ability to increase energy and focus has even led some people to refer to it as the "poor man's cocaine." There have been reports of people using ADHD stimulants that weren't prescribed for them. People have crushed and snorted Ritalin tablets or dissolved the drug in water and taken it intravenously. Studies show that abusing Ritalin can lead to dependence on the drug. When carefully taken as prescribed, though, Ritalin is less likely to be addictive in children or adults. In large doses -- greater than what is typically prescribed for ADHD -- Ritalin does have effects similar to those of cocaine. However, researchers have found marked differences between the two drugs. One of the factors that leads to addiction and drug abuse is how quickly a drug raises dopamine levels. The faster dopamine levels go up, the greater the potential for abuse. One researcher found that Ritalin takes about an hour to raise dopamine levels in the brain, compared to only seconds with inhaled cocaine. The doses of Ritalin and other stimulants used to treat ADHD tend to be lower and longer-acting, which reduces the risk of addiction. Long-term use of all stimulants can sometimes lead to a phenomenon called tolerance -- that is, higher doses are needed to achieve the same effect of a controlled substance. If and when this happens, a doctor may then be more likely to consider using nonstimulant medicines to treat ADHD. Many parents are concerned that giving their children stimulants to treat ADHD might lead the children to start experimenting with other types of drugs. Several studies have set out to investigate the possible link between prescribed ADHD stimulant medication and substance abuse problems, and there doesn't appear to be a strong connection. One of the longest-term studies, which followed 100 boys with ADHD for 10 years, showed no greater risk for substance abuse in boys who took stimulant drugs compared to those who didn't take the drugs. An earlier study by the same authors even suggested that stimulant use might protect against later drug abuse and alcoholism in children with ADHD by relieving the ADHD symptoms that often lead to substance abuse problems. The earlier the stimulants are started, the lower the potential for substance abuse down the road. It's important to remember that not everyone with ADHD will develop an alcohol or substance abuse problem. In adults who do develop a problem, doctors suggest treatment with nonstimulant medications, including guanfacine ( Tenex, Intuniv), Clonidine ( Kapvay), or atomoxetine ( Strattera), and sometimes certain antidepressants such as Desipramine ( Norpramin) and Bupropion ( Wellbutrin). Whether Ritalin and other stimulants are effective treatments for ADHD patients with substance abuse problems is less clear. These drugs may be useful when prescribed in a long-acting form and in a controlled way to minimize the risk for becoming physically dependent on or misusing them. Individual or group therapy, as well as 12-step support groups, can also be an important part of the substance abuse program for people with ADHD.