It may seem a bit odd, but the Vietnam War provided a powerful example of how to change bad habits. At one point, it was estimated that 15 percent of U.S,. Servicemen were addicted to heroin. But instead of shipping them home, the military placed them in treatment programs in Vietnam. Ordinarily, the relapse rate for heroin addicts is very high, but only 5 percent of servicemen in the treatment program became addicted again when they got home.