General Resources Substance Abuse and Mental Health Services Administration SAMHSA's mission is to reduce the impact of substance abuse and mental illness on America's communities. National Institute on Drug Abuse A part of the National Institutes of Health, NIDA's mission is to lead the Nation in bringing the power of science to bear on drug abuse and addiction. Drug Abuse Warning Network – DAWN Public health surveillance system that monitors drug-related visits to hospital emergency departments and drug-related deaths investigated by medical examiners and coroners.