While exact definition of addiction varies, it is generally considered to be a condition in which an individual persists in use of alcohol or another substance despite problems related to its use. Compulsive and repetitive use often results in tolerance, where more of the substance is needed to achieve the same effect, as well as withdrawal symptoms if use of the substance is cut back or stopped.
Almost everyone knows someone affected by addiction or substance abuse. The National Institute on Drug Abuse (NIDA) estimates that each year approximately 40 million debilitating illnesses or injuries occur among Americans as the result of their use of tobacco, alcohol, or another addictive drug. Addiction and substance abuse is not just an individual problem, but one that affects families and communities. NIDA estimates substance abuse costs the United States an estimated $484 billion per year.