Dopamine: The Key to Addiction?

Researchers nationwide have been focusing a lot of attention on dopamine – a chemical produced by the human brain – in an effort to unlock the riddle of addiction. So far, dopamine has been linked to several fundamental physiological processes, and plays key roles in pleasure, addiction and even disease. Researchers are now exploring ways to manage dopamine in order to harness the positive effects and minimize the negative effects that this tiny molecule can have on the human body.

Dopamine is a tiny molecule, consisting of only 22 atoms. It is both essential to life and a player in several unpleasant and even life-threatening conditions such as drug addiction, impulsiveness, obesity, Parkinson’s disease and restless leg syndrome. The brain releases dopamine in response to certain activities, including eating, exercise, sexual activity and drug use. The release of dopamine allows brain cells to communicate with one another, and its presence facilitates the ability to experience pleasure. Because of this, people tend to repeat activities that trigger the release of dopamine.

Dr. Jay Giedd, a psychiatrist at the National Institute of Mental Health in Rockville, Maryland, explained the mechanism in a radio interview earlier this year: “If we make good decisions, our dopamine goes up. It tells our brain, you know, good call, that was the right move, you know, do that again next time, and it literally changes the anatomy of the brain. It strengthens certain connections. It decreases others.”

The dopamine release mechanism may be designed to reward “good behavior,” as Dr. Giedd posits; however, what his explanation overlooks is that the body also releases dopamine in response to unhealthy and destructive behaviors such as drug use and risk-taking. Substances such as cocaine, amphetamines and nicotine overload nerve circuits in the brain with dopamine; causing extreme sensations of pleasure which addicts learn to crave. They repeat the use of substances to keep achieving this high.

Low levels of dopamine have also been linked to obesity. Some experts believe that low levels of the brain chemical cause some individuals to overeat because they don’t experience normal levels of pleasure with the consumption of normal amounts of food.

In addition, medications that stimulate dopamine production have been shown to have some strange effects. One study recorded that patients taking one of these medications (to help treat Parkinson’s disease, which is also correlated with low dopamine levels) began compulsively gambling, with no history of ever being interested in games of chance.

A recent breakthrough in dopamine management is the development of a potential cocaine vaccine. Dr. Nora Volkow, director of the National Institute on Drug Abuse (NIDA), recently announced the first successful preliminary test of a possible cocaine vaccine. Researchers at Yale University found that a shot of the vaccine reduced cocaine use in 38 percent of study participants.

Like vaccines for infectious diseases, the cocaine vaccine causes the human body to produce antibodies to cocaine. When cocaine is ingested, the antibodies bind themselves to the cocaine molecules in the blood and prevent them from entering the brain and producing a high. If the cocaine does not enter the brain, it cannot trigger the release of dopamine, which is what creates the sensation of pleasure that cocaine users experience.

The study, which appeared in the most recent issue of the journal Archives in General Psychiatry, tracked the progress of 115 people over 12 weeks. Participants were randomly assigned to receive either the vaccine or a placebo.

Dr. Volkow commented on the results: “The results of this study represent a promising step toward an effective medical treatment for cocaine addiction. … Provided that larger follow-up studies confirm its safety and efficacy, this vaccine could offer a valuable new approach to treating cocaine addiction, for which no FDA-approved medication is currently available.”

Dr. Anna Childress, a psychiatrist at the University of Pennsylvania School of Medicine in Philadelphia, commented on the quest to control dopamine: “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. … We have a brain hard-wired to appreciate rewards, and cocaine and other drugs of abuse latch onto this system.”