Read the following information from this link. I didn't copy all of it, so you can access the whole article through this link.

http://www.mentalhelp.net/poc/view_d...&id=13864&cn=3

Addiction Issues with ADHD Medications

Margaret Austin, Ph.D., Natalie Staats Reiss, Ph.D., and Laura Burgdorf, Ph.D. Updated: Nov 5th 2007

One concern that frequently arises around prescribing ADHD medication is that stimulant use will lead to substance abuse. The federal government agrees that stimulants have a high abuse potential and has labeled them accordingly (i.e., classifying them as Schedule II medications). Yet, research examining the behaviors of adults and adolescents with ADHD does not show an increased risk of substance abuse with medication usage. In fact, data suggests that the opposite is true: individuals with ADHD who use stimulant medication to control their symptoms are less likely to become addicts than are individuals with ADHD who are not on medication. In addition, research shows that treating ADHD with stimulant medication appears to reduce the risk of later substance abuse problems by half.
The dramatic positive impact that medication can have on the lives of individuals with ADHD cannot be overstated. Individuals with ADHD who take medication usually experience consistency across their days, something that they may never have experienced before. Most patients learn to manage their medication and have little need to increase the dose once an effective level has been reached. Neither tolerance (medication effects that decrease over time with the same dose) nor withdrawal (physiological or bodily dependence on medication) appears to be an issue for individuals with ADHD. Some adults may actually find that they respond to lower doses of medication and reduce their dosages over time. In addition, stimulant medication may actually provide a protective effect for some individuals with ADHD and decrease the likelihood of needing to use other substances to control their symptoms.