The 2009 TIME 100

David Sheff wrote a beautiful book called, appropriately enough, Beautiful Boy — A Father's Journey Through His Son's Meth Addiction, one of the most compelling portrayals I've ever read of a parent's loss of a child to drugs. In this journey, Sheff, 53, faces the overdose of his son Nic and his inability to protect him, the relapses that inevitably occur and the family's struggle to cope with it all.

Many people still call addiction a moral failing. But 20 years of research tells us that it's a disease that results in part from the damage that abused drugs do to the brain circuits required for self-control. Unfortunately that damage is long-lasting, meaning that the person remains vulnerable to relapse even after years of successful rehabilitation.

Sheff's experiences highlight how poorly our society addresses addiction. We treat the medical consequences of the problem (overdoses, car accidents, cancer, HIV, mental illnesses) but not the disease itself. Our investments in research and services for addiction treatment are a fraction of the costs associated with drug-related incarceration and lost productivity. Yet punishment and stigmatization do nothing to ameliorate the problem. How could they, when about 50% of addiction is rooted in our genes and much of the rest is due to social and cultural factors such as stressful childhood experiences?

Nic Sheff is alive today thanks in great measure to the devotion and resourcefulness of his extraordinary family. But many others have not been so fortunate. David Sheff's voice resonates loudly and makes us pause and ask why, despite our understanding of addiction as a brain disease, we fail to treat it as we do other medical illnesses.

Volkow is the director of the National Institute on Drug Abuse