Subconscious Signals Can Trigger Drug Craving

Images of cocaine and drug paraphernalia can trigger craving in the brains of addicts even when they are not aware that they have seen anything, according to a study using brain imaging technology. Cocaine-related images flashed in front of addicts for only 33 milliseconds triggered activity in the brain's emotion and reward system.

Using functional magnetic resonance imaging (fMRI) researchers at the University of Pennsylvania showed addicts photos of crack pipes and chunks of cocaine. But the pictures flashed by so quickly the addicts were not consciously aware of seeing them.

Regardless, the images stimulated activity in the limbic system, the part of the brain involved in emotion and reward.

Overwhelming Desire for Drugs

"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 Dr. 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."

Two days later, the researchers showed the addicts the photos again, but allowed them to look at them for a longer period of time. The addicts who had the strongest brain response to unseen cues in the fMRI test, also felt the strongest positive association with visible drug cues, the researchers said.

Lead author of the study, Dr. Anna Rose Childress, said the study could lead to improved treatment approaches.

"We have a brain hard-wired to appreciate rewards, and cocaine and other drugs of abuse latch onto this system," Childress said in a news release. "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."

The study, "Prelude to Passion: Limbic Activation by 'Unseen' Drug and Sexual Cues" was published Jan. 30, 2008 in the journal PLoS One.

Related Information:

• What Is Substance Abuse?
  
• Are You Addicted?
  
• How to Quit Alcohol and Drugs

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