Research by Lancet, the British medical journal, finds that cocaine is the second most harmful drug after heroin, and the Legal Institute of Medicine in Seville states that there is no such thing as a safe amount of the drug. So why do so many people become dependent on cocaine? Research from leading universities and labs around the world is piecing together the answer. What they are finding is that cocaine addiction is far from simple, and that it affects the brain in ways we are only just beginning to understand.
Cocaine’s effect on the brain
The brain produces chemicals called neurotransmitters which relay information between nerve cells called neurons. This process controls all of the body’s functions from heartbeat to appetite. Once these neurotransmitters have done their job they are reabsorbed back into the neuron that released them. The brain recycles these chemicals in a closed loop system. Cocaine interrupts this process for three important neurotransmitters; dopamine, serotonin and norepinephrine.
Dopamine is most often associated with sensations of pleasure, but it also plays a pivotal role in the central nervous system. Any pleasurable sensation, from a pleasant aroma to a hug from a loved one will trigger the release of dopamine.
Serotonin has many functions in the body, including the control of appetite, body temperature and sleep-wake cycles. It also plays a key role regulating mood swings and anger.
Norepinephrine helps the body in a fight or flight situation by increasing blood flow and heart rate, and releasing glucose for instant energy.
Cocaine works by preventing these neurotransmitters from being reabsorbed by the neuron that released them. The neurotransmitters than accumulate in the brain, intensifying their effects. This is why cocaine users report feelings of euphoria and pleasure. It’s also the reason they lose their appetite, have trouble sleeping and feel jittery.
The body does not have an inexhaustible supply of these neurotransmitters, and they take time to produce. This means a cocaine user will deplete their stores rather quickly with prolonged use. This in turn leads to a compromise in the body’s ability to function. Cocaine users will lack energy and will no longer enjoy things that once gave them great pleasure. A downward spiral then ensues where feelings of depression and anxiety lead to greater cocaine use, which in turn leads to fewer neurotransmitters, which heightens the depression. The end result is a cocaine addict takes more and more of the drug for a gradually decreasing reward. This shortage of neurotransmitters is also a major cause of relapse during recovery. Hopelessness, lethargy and depression are all common until the brain has had a chance to restore its chemical balance.
Rewiring the reward center
Research at the Mount Sinai School of Medicine has shed further light on cocaine’s addictive properties. The study observed the nucleus accumbens section of the brain, which plays an important role in the brain’s reward mechanism. The study found that exposure to cocaine caused an imbalance in two of the neurons in the nucleus accumbens. Cocaine caused an increase in the activity of D1 neutrons and a decrease in D2 neurons. This distortion of the brain’s natural reward system is another example of how cocaine changes the way the brain works.
How genes and gender may play a part
The stories of rats choosing cocaine over food to the point of starvation may have been exaggerated, but recent studies using the rodents have shown that there may be a gender bias in cocaine addiction. The University of California observed hungry rats that were given the choice of cocaine or food. Female rats chose the drug 75 to 80 percent of the time compared, to 50 percent in males. Researchers believe that female hormones may be responsible as female rats that had their ovaries removed chose the food at the same rate as male rats.
Scientists at Cambridge University may have come across a genetic predisposition to cocaine addiction. They scanned the brains of 60 cocaine addicts and found that their basal ganglia were enlarged. The basal ganglia has an important role in the brain’s reward mechanism, so these findings were not unexpected. What the scientists were puzzled by was the lack of correlation between the enlargement and the length of cocaine use. This led them to conclude that the basal ganglia in these addicts were large before they started using the drug, and that it may be partly responsible for their addiction.
Adding alcohol makes things worse
Frequently cocaine users mix the drug with other drugs, or more frequently alcohol. Cocaine is a volatile drug at the best of times, and when taken along with other unregulated street drugs the results can be, and often are tragic. However, taking cocaine with alcohol enhances the drugs addictive properties. When cocaine and alcohol are both present in the bloodstream, the liver will produce additional cocethylene. This works to enhance the euphoric effect of the drug and speed up the vicious cycle of addiction. An increase in cocaethylene also greatly increases the chance of sudden death when using cocaine.
Cocaine changes gene expression
Scientists at the National Institute on Drug Abuse have identified another way that cocaine contaminates the brain and addicts its users. They noticed that cocaine affected an epigenetic process called histome methylation. By repressing an enzyme called G9A, cocaine changes the brains reward pathways. This led to changes in gene expression, and a strong preference for cocaine.
Crack is a smokeable form of cocaine made by processing the drug with baking soda and water. The much publicized addictive quality of crack is based on it being smoked rather than snorted. Smoking delivers the drug’s effects more rapidly and temporarily, leading to faster addiction. The crack abuse that swept the country in the 1980s was a result of introducing cocaine to a much wider audience.
There is a great deal of myth surrounding cocaine addiction, and the type of people that abuse the drug. Many have seen firsthand how the drug seizes its users and how they end up using more and more of the drug for less and less return. This is frequently written off as a deficiency of character, or a simple lack of will power. The science tells us a different story. Research from around the world is looking into cocaine and unearthing more of its insidious secrets. Each research project is another piece of the puzzle, and discovers a new way that cocaine hijacks the brain and enslaves its users.