Alcohol eases the path that leads from casual cocaine use to outright addiction according to latest research conducted at Columbia University’s Mailman School of Public Health and Columbia University Medical Center. While most people who use an illicit drug do not go on to develop addiction, the study helps explain why an early exposure to alcohol can tip the balance and increase a person’s vulnerability to developing addiction to cocaine.

The paper was published in the journal Science Advances.

In the study, durable chemical changes were seen in rats that were primed with alcohol that make them more susceptible to dependence on cocaine. These changes in the brain resulted from mechanisms that turn genes on and off in the brain’s reward centers, creating a “permissive environment” for addiction, according to the study authors. Drinking alcohol for two hours a day over 11 days and then given access to cocaine for various stretches over the next 32 days led to their drug-seeking behavior.

The results parallel and extend the findings from previous studies on nicotine conducted by the same team of investigators, Drs. Denise and Eric Kandel and Dr. Edmund Griffin, in collaboration with Dr. Amir Levine, from the Department of Psychiatry, at Columbia Medical Center. “Our results were as predicted according to the gateway hypothesis,” said Denise Kandel, PhD, professor of Sociomedical Sciences at the Mailman School of Public Health and research scientist at the New York State Psychiatric Institute. “People use nicotine and alcohol before using cocaine.”

An estimated 21% of those who use cocaine on an occasional basis wind up taking the drug compulsively.

While population studies have suggested that both alcohol and nicotine were gateways to illegal drugs, the finding of this common gateway pathway between nicotine and alcohol provides biological underpinning for the progression and opens up new opportunities in prevention research.

“The findings demonstrate how an early exposure to a drug like alcohol can increase a person’s vulnerability to developing an addiction to cocaine and other drugs,” said Denise Kandel. “Our research further indicates the importance of targeting intervention programs in earlier stages of development – adolescence and young adulthood. Since alcohol and nicotine use take place before cocaine use in adolescence and early adulthood you have to begin studying these early developmental stages.”