Cocaine is a powerful, addictive stimulant drug known for its ability to significantly alter brain function in regular users. Some regular users have symptoms that qualify them for a diagnosis of cocaine addiction, while others do not. In a study scheduled for publication in 2014 in the journal Addiction, researchers from the Medical University of South Carolina compared certain brain changes found in non-addicted cocaine users to changes found in the brains of addicted users. These researchers concluded that the length of time over which a person uses cocaine may be a more critical factor in the observed brain alterations than the absence or presence of cocaine addiction.
Cocaine Use and Cocaine Addiction
Cocaine produces its stimulating effects by speeding up nerve cell interactions inside the brain and spinal cord (central nervous system). The drug produces its basic mind-altering effects by changing the chemical balance in a brain area called the pleasure center; this alteration yields a powerful sensation called euphoria. The duration and intensity of these drug effects depend on factors that include the amount of the drug used, the form of the drug used (powdered cocaine vs. “crack” cocaine) and the method used to introduce cocaine into the body.
Repeated exposure to cocaine can produce persistent changes in the way the brain’s pleasure center functions. These changes signal the arrival of physical dependence, a condition marked by a continuing need to consume more of a substance in order to feel “normal.” In turn, physically dependent cocaine users commonly develop additional symptoms that characterize the onset of a cocaine addiction. Specific symptoms of such an addiction can include loss of the ability to regulate cocaine intake, a recurring urge to seek out more of the drug, decreasing sensitivity to the cocaine’s drug effects and the appearance of cocaine withdrawal when the accustomed amount of the drug is not consumed. Cocaine addiction is one aspect of a larger diagnosable condition called stimulant use disorder.
Additional Brain Effects
In addition to affecting the pleasure center, cocaine exposure can also lead to altered function in other areas of the brain. For example, the drug can alter certain higher-level functions that give a person the ability to remain fully in control of his or her behavior. A person who regularly consumes cocaine can also develop conscious and unconscious drug cues that make it more likely that he or she will use the drug when confronted with mental states or social settings previously linked with cocaine use. Several areas of the brain help determine an individual’s ability to control his or her behavior, as well as his or her sensitivity to drug use cues.
Length of Cocaine Use
In the study scheduled for publication in Addiction, the Medical University of South Carolina researchers used a real-time scanning technology called fMRI (functional magnetic resonance imaging) to examine the brains of cocaine users and determine which factors help explain cocaine-related loss of behavioral control and drug cue sensitivity. A total of 51 people participated in the study; forty-one of these individuals had a diagnosable addiction to cocaine, while the remaining 10 participants did not. The three specific factors under consideration were the presence or absence of addiction, the number of years over which cocaine use occurs and a history of cocaine use in the last three months.
The researchers concluded that all of the study participants experienced at least some of the brain changes associated with reduced behavioral control and heightened sensitivity to cocaine cues. When they looked at the factors most likely to lead to such brain changes, they concluded that the most important variable is apparently the number of years over which a person uses cocaine. This finding held true in relation to both the presence or absence of cocaine addiction and a recent history of cocaine intake. It also held true irrespective of the age of the affected individual.
The study’s authors did not definitively determine that length of cocaine use is more important than cocaine addiction when it comes to certain forms of brain change. However, they believe that their findings establish such a conclusion as a reasonable possibility. Further research will be needed to further clarify the relative impact of the various factors that can contribute to cocaine-related behavioral control problems and drug cue susceptibility.