Many scientists now agree that genetics and environment play about equal roles in addiction. And researchers recently identified brain differences in addicts that may eventually lead to treatments that eliminate drug cravings. But with U.S. addiction rates remaining steady at about 9 percent of the population, the secret to who stays hooked and who breaks free - either through treatment or by their own efforts - remains a mystery. As a result, debate still rages over whether health insurance should cover more addiction treatment. Advocates for addicts also argue that states should reduce tough penalties for drug offenders, such as depriving ex-felons of the right to vote. Recovered addicts are banding together to lobby for better insurance and an end to laws that stigmatize substance abusers. But opponents argue that treating addiction as a disease, not a choice, merely encourages some people to continue abusive behavior.

Marcia Clemmitt is a veteran social-policy reporter who joined CQ Researcher after serving as editor in chief of Medicine and Health, a Washington-based industry newsletter, and staff writer for The Scientist. She has also been a high school math and physics teacher. She holds a bachelor's degree in arts and sciences from St. Johns College, Annapolis, and a masters degree in English from Georgetown University.