Trying to kick drug addiction without medicines is said to be like relying on willpower to overcome diabetes or asthma. Enter naltrexone, which has been around since 1984 and reduces the cravings for drugs and alcohol by fine-tuning the brain's chemical reward system. Why has it recently increased in popularity? How does it compare to similar strategies? Has it made a difference? Our authors, who have long studied addiction and the brain, confront a drug and alcohol addiction problem that today kills more Americans each day than gun violence or car accidents.