NIDA's MDD is faced with the formidable task of identifying, characterizing, and developing new chemical entities to combat substance abuse. The primary challenge is to find one or more medications that will be useful in treating cocaine addiction, withdrawal, and abstinence. In addition, a treatment for cocaine overdose is in progress. Methodological approaches include testing compounds that alter endogenous neurotransmitters and compounds that suppress conditioned cues and stimuli. Compounds that appear efficacious in these tasks and that have a satisfactory safety profile will be studied in humans.