Cocaine Abuse Affects Decision Making, Memory

Finding May Explain Abuse Relapse

Mom Snorting Cocaine
Cocaine Affects Memory, Decision-Making. © Getty Images

Long-term cocaine users can lose some of their ability to memorize and remember even simple items and can have their decision-making abilities impaired, according to a MRI examination of the brains of cocaine abusers.

Chronic cocaine abuse is directly related to dysfunction in areas of the brain involved in higher thought and decision-making. Researchers say the resulting cognitive deficits may help explain why cocaine abusers persist in using the drug or return to it after a period of abstinence.

The study was conducted by Dr. Robert Hester of Trinity College in Dublin, Ireland, and Dr. Hugh Garavan of Trinity College and the Medical College of Wisconsin in Milwaukee.

Damage to the Dopamine System

"Addictive substances such as cocaine can damage the dopamine system in the brain, and there is a high concentration of dopamine receptors in brain regions involved in higher-order decision-making processes," says NIDA Director Dr. Nora D. Volkow, in a news release. "By employing functional neuroimaging to examine the neural changes that often result from chronic cocaine abuse, these scientists have identified another aspect of cocaine's effect on the brain that may help explain why individuals persist in these behaviors despite the negative consequences."

In the study, the scientists enlisted 15 active cocaine abusers and 15 healthy individuals who have never used the drug. Each participant completed a task in which they viewed memory lists of letters for six seconds and "rehearsed" each list for 8 seconds.

They later pressed a button when they were presented with a letter that was not part of the preceding list. During the task, the participants' brains were analyzed via functional magnetic resonance imaging (MRI) that illustrates nerve cell activity during the performance of a specific task.

Cocaine Affects Higher Brain Functions

The cocaine abusers were significantly less accurate than the controls.

The scientists found that the demands of working memory required increased activation of two brain regions, the anterior cingulate cortex (ACC) and the prefrontal cortex.

"Previous research that examined cognitive function in cocaine abusers identified decreased activity in the anterior cingulate cortex," says Dr. Garavan. "But our study is the first to show that the difficulty cocaine users have with inhibiting their actions, particularly when high levels of reasoning and decision-making are required, relate directly to this reduced capacity for controlling activity in the ACC and prefrontal regions of the brain."


Garavan, H and Hester, R. "Executive Dysfunction in Cocaine Addiction: Evidence for Discordant Frontal, Cingulate, and Cerebellar Activity." The Journal of Neuroscience December 2004

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