Drug "czar" General Barry R. McCaffrey last night touted the Clinton administration's success in reducing drug use among adolescents, in a speech at the Kennedy School of Government's ARCO forum.

But McCaffrey acknowledged the administration has faced pitfalls during his five-year tenure as director of the Office of National Drug Control Policy.

The visit to Harvard came three days after McCaffrey announced his intention to resign with the change in administration this January.

McCaffrey's speech, "The War on Drugs: A Report Card," touched on controversial issues involving drug treatment programs, international interdiction efforts and perceived racial discrepancies in domestic enforcement.

McCaffrey prefaced his remarks by calling the drug issue "by far the most difficult, the most important" of the issues he has addressed in his 40 year public service career.

Speaking in a manner many who attended described as forthright, McCaffrey reviewed arguments for a coherent drug policy.

"The drug issue is not that complex. The problem doesn't pose intellectual issues like poverty. The science of neurochemistry of the brain and chronic addiction is well understood," McCaffrey said.

McCaffrey expressed regret that he leaves his office as statistics show that drug use among those aged 18 to 25 is on the rise. He also noted that the economic costs of drug and alcohol abuse has grown steadily since 1985.