Researchers say that showing subliminal images of cocaine to addicts triggers activity in the limbic system, a part of the brain involved in emotional response.

"This is the first evidence that cues outside one’s awareness can trigger rapid activation of the circuits driving drug-seeking behavior," said NIDA director Nora Volkow. "Patients often can’t pinpoint when or why they start craving drugs. Understanding how the brain initiates that overwhelming desire for drugs is essential to treating addiction."

"We have a brain hard-wired to appreciate rewards, and cocaine and other drugs of abuse latch onto this system," noted researcher Anna Rose Childress of the University of Pennsylvania. "We are looking at the potential for new medications that reduce the brain’s sensitivity to these conditioned drug cues and would give patients a fighting chance to manage their urges."