How to Break the Chain.(alcoholism)

Byline: Michael Craig Miller, M.D. (MILLER is editor in chief of the Harvard Mental Health Letter. For more information, visit health.harvard.edu/NEWSWEEK.)

Remember "Just say no"? It was a slick motto, but a terrible remedy for drug and alcohol dependence. Decades later, tens of millions of people are wrestling with addiction. This disease costs an estimated 0.5 percent to 1.3 percent of gross national product each year. The problem is not flawed character; it's skewed brain function. Fortunately, scientists are now well on their way to understanding how addiction changes the brain, and this knowledge is starting to yield treatments that work.

Addictive substances hijack the brain's reward system, weakening our resolve to make wise choices, even when painful consequences are sure to result. Specifically, they stimulate the release of the chemical messenger dopamine into a region of the brain called the nucleus accumbens. Cocaine and other stimulants cause this change directly. Other substances--alcohol, narcotics, nicotine and marijuana--act indirectly. But in each case, the sensation is self-reinforcing. Feel it once and you want to feel it again.

This common pathway begs for a magic-bullet treatment, but the cycle of addiction is actually more complicated. It involves multiple chemical messengers, not just dopamine. The good news is that each of these messengers offers a possible target for treatment, and researchers are taking aim at them. The clearest recent advance is a new group of medications that work to combat craving. The archetype, a compound called naltrexone, reverses the pleasurable effect of narcotics like heroin. It also slows the release of dopamine in the nucleus accumbens. Recovering alcoholics tend to experi-ence less euphoria when they drink while taking naltrexone, and their chances of staying in recovery improve. But the drug is far from curative. It doesn't completely extinguish the desire to drink, and people who lack counseling and support often have trouble taking it every day. A new long-acting form of naltrexone could reach the clinic ...