"Unfavorable preliminary findings from the evaluation were reported by Westat in 2002. Beginning in 2002, ONDCP [Office of National Drug Control Policy] took a number of steps that were intended to strengthen the power of the campaign to achieve positive results. These steps included more rigorous ad copy testing and a concentration on anti-marijuana messages. However, the post-2002 results yielded no evidence of positive impacts and some evidence of negative and unintended consequences in relation to marijuana use. Specifically, exposure to advertisements during the redirected campaign was associated with higher rates of marijuana use initiation among youth who were prior nonusers of marijuana."

Source

General Accountability Office, "ONDCP Media Campaign - National Evaluation Did Not Find That the Youth Anti-Drug Media Campaign Was Effective in Reducing Youth Drug Use," Washington, DC: report to the Chairman and Ranking Member, Subcommittee on Transportation, Treasury, the Judiciary, Housing and Urban Development, and Related Agencies, Committee on Appropriations, U.S. Senate, August 2006, GAO-06-818.