The real value of the new research may be that these receptors can provide new and more effective therapies for current addicts, says Michael Nader, a physiologist and pharmacologist at the Wake Forest University School of Medicine in Winston-Salem, N.C. "This identifies a target," he says. "If you have low D2 levels you're more vulnerable; if you change the environment, you can increase those levels." He suggests that treatments that stimulate production of D2 receptors could be beneficial.
"Most licensed treatments are substitution therapies"such as methadone in the case of heroin addiction"so they maintain the addicted state, but more safely," says Dalley. "We feel that newer treatments should aim to prevent relapse." He notes that the behavior of the impulsive study rats normalized after they went through withdrawal from cocaine. "The potential here," he says, "is [in] treatments that retard the return of impulsivity in post-cocaine addicts, [which] may be an important contributor to relapse."