A brain imaging study conducted by researchers at Massachusetts General Hospital revealed that abnormalities appearing in the cerebral cortex of cocaine addicts correlate with dysfunction in regions of the brain responsible for attention and reward-based decision-making. 

While some of these abnormalities may reflect a predisposition to drug use, others may result from long-term cocaine exposure. "These data point to a mixture of both drug effects and predisposition underlying the structural alterations we observed," said Hans Breiter principal investigator of the Phenotype Genotype Project in Addiction and Mood Disorder.

Magnetic resonance imaging studies of 20 cocaine addicts and 20 control participants were used to determine variations in cortical thickness. Compared to the healthy controls, the cocaine addicts had significantly less overall cortical volume. The difference was markedly apparent in areas that control reward functioning and decision-making. In addition, typical differences in thickness in the frontal regions of the cortex was reversed for the addicts compared to non-addicts.

"The severity of these cortical alterations point to the potential importance of prevention efforts to keep susceptible individuals from beginning to use cocaine," Breiter said. He suggested that further large-scale testing of individuals with different addictions is needed "to see if these findings are limited to cocaine users."

The report appears in the Oct. 9, 2008 issue of the journal Neuron.