The root of the word “addiction” comes from the Latin word for “enslaved by“, which is exactly what addiction represents in most cases. Addicts become so dependent on the addictive substance that they are enslaved by it.
Addiction influences the brain to such an extent that it causes cravings for the substance of addiction, continuing use of the substance even with negative outcomes and loss of control over its use.
What Causes Addiction?
For a long time, scientists believed that only substances like drugs and alcohol caused addiction, however today it’s known that addiction can be caused by some pleasurable activities such as shopping, sex and gambling.
No one wants to be an addict, but addiction is a growing problem. Nearly 23 million Americans are addicted to drugs and alcohol. When researchers began studying addiction in the 1930s, they thought that addicts were morally deficient or did not have enough willpower to beat the addiction. Research has shown that those beliefs were erroneous and that addiction is a chronic disease that affects the brain’s ability to function.
The brain recognizes all feelings of pleasure in the same way, no matter the source. Pleasure results in the release of dopamine in the nucleus accumbens, or the brain’s pleasure center. When abusers use their drug of choice, it causes a sizable release of dopamine. Addiction is linked to the intensity and speed of the dopamine release.
Development of Addiction
Pleasure alone is not the cause of addiction. While dopamine adds to the sensation of pleasure, it also enhances memory and learning. Dopamine interacts with glutamate, and takes over the brain’s process of reward-related learning. This system links activities needed for survival such as eating to pleasure and reward.
Repeatedly exposing yourself to any addictive substance will result in driving yourself to go after it.
Over time, the brain does not derive as much pleasure from the same amount of the addictive substance, releasing less dopamine. In turn, you need more of the drug to achieve the same amount of pleasure. The brain becomes overwhelmed with the increasing amount of the substance needed.
Because of this reaction, people who are addicted often find that over time the addictive substance doesn’t give them as much pleasure and they need to take more of it to get the same “high.” This effect is called tolerance.
Eventually, compulsion is the result. The pleasure from the drug or behavior goes away, but the memory of the effect and the desire to continue recreating it persists. The normal process becomes broken. The memories stored in the hippocampus and amygdala are retrieved to create a conditioned response. The conditioned response or craving helps contribute to addiction and relapse after recovery.
Memories of items related to the addiction can also trigger a craving. For instance, if an alcoholic sees a bottle of whiskey, they may start drinking again. Conditioned learning is one reason why people who become addicts may relapse after many years of sobriety.
- Understand Addiction, HelpGuide.org, Harvard Medical School, http://www.helpguide.org/harvard/how-addiction-hijacks-the-brain.htm
- Nora D. Volkow, M.D., Drugs, Brains, and Behavior: The Science of Addiction, National Institute on Drug Abuse, July 2014, http://www.drugabuse.gov/publications/drugs-brains-behavior-science-addiction/preface