There are various factors that contribute to addiction. Some are genetic, others environmental, or learned, and some biological. For this article, we will be focusing on the biological factors that influence addiction. Addiction is a serious disease that can impair, delay, or stunt brain development.
Imaging studies of the brain in drug-addicted participants, have shown neurochemical and functional changes [1]. Neurochemical studies show that large and fast increases in dopamine are associated with the reinforcing effects of drug abuse, but also continue after drug abuse and withdrawal. These images show that dopamine in the brain is markedly decreased and typically are associated with dysfunction in the prefrontal regions of the brain [1].
Biological Influences on Addiction Development
There are three types of occurrences within the brain that characterize addiction. First is the craving or preoccupation/anticipation phase, the second is binge/intoxication phase, and thirdly the withdrawal/negative affect phase. Impulsivity and positive reinforcement are often dominate urges in the first phase, which drives motivation for drug seeking behavior. Compulsivity and negative reinforcement dominate the last two phases of the addiction cycle [3].
Three phases characterize the addiction cycle. First is craving or preoccupation/anticipation phase, secondly the binge/intoxication phase, and third the withdrawal/negative affect. Typically impulsivity and positive reinforcement of drug seeking behavior occurs in the first phase while compulsivity and negative reinforcement is seen in the latter two phases [3].
Addictive drugs can alter the adaptive changes in gene expression in the brain’s reward system. This shows a level of tolerance and habit formation with craving and negative effect that can persist long after the addiction ends.
The Role Genetics Plays in Addiction
Looking at the genetic influences of addiction, it leads us to examine the biological influences of addiction. There are four circuits involved in drug abuse and addiction. First is the reward system, which is located in the nucleus accumbens (NAc) and the ventral pallidum.
Second is the motivation and drive center which is located in the orbitofrontal cortex (OFC) and the subcallosal cortex.
Third is the memory and learning region which is located in the amygdala and hippocampus, and fourthly, control is located in the prefrontal cortex and anterior cingulate gyrus (CG) [1].
With biological influences each person’s unique physical makeup and genetics play a role in the development of addiction. Each individual differs in the degree to which they like a particular substance or not. The same is true for the ability to modulate impulsive desires with rational thought [2]. Some people can manage impulses but others not.
A study from Cambridge University found a biological trigger in the brains of drug users, is believed to be the cause of the switch from occasional use to compulsion and addiction [4]. This switch from recreational to addictive use occurs when one’s control over desire for the substance transfers from the ventral stratum of the brain, linked with pleasure and reward, to the dorsal striatum, associated with the development of habits [4].
Addiction Symptoms Influenced by the Brain
There are many areas in the brain that are affected by addiction, and symptoms are identified that correspond with these areas. The cerebral cortex is associated with impaired decision making, impulsivity, and compulsivity. The reward system is responsible for drug-seeking and cravings.
Our brains are hardwired to seek rewards to ensure survival, and reward behaviors that are pleasurable. When individuals are addicted to alcohol and drugs, our regulatory system is dysregulated in the reward, pleasure, and impulse control regions of the brain, as mentioned above [5].
Our amygdala is associated with memory and emotion, and triggers are stored in our brain as positive and negative memories. When a trigger occurs, like increase stress or feelings of being overwhelmed, or shame, guilt, etc., the trigger creates a powerful motivator to use a substance and contributes to relapse within individuals working through their recovery. The same is true for those starting recovery and going through withdrawal.
The memory stored in the brain regarding the withdrawal processes is an unpleasant experience that can serve as a powerful motivator to relapse and begin using again to avoid going through withdrawal.
When addicts show difficulty in deferring gratification, it shows that there is a neurological locus of problems in the frontal lobe [5]. If addiction occurs in early adolescence, it can change the development or non-full development of frontal lobe functioning [5].
In conclusion, the brain plays a central role in the influence of addiction, especially those with reward and pleasure. Addiction affects impulse control, impulsivity, and further seeking of the substance. Biological factors can influence a person’s ability to inhibit cravings, manage triggers, and relapses when attempting recovery.
About the Author: Libby Lyons is a Licensed Clinical Social Worker and Certified Eating Disorder Specialist (CEDS). Libby has been practicing in the field of eating disorders, addictions, depression, anxiety and other comorbid issues in various agencies. Libby has previously worked as a contractor for the United States Air Force Domestic Violence Program, Saint Louis University Student Health and Counseling, Saint Louis Behavioral Medicine Institute Eating Disorders Program, and has been in Private Practice.
Libby currently works as a counselor at Fontbonne University and is a Adjunct Professor at Saint Louis University, and is a contributing author for Addiction Hope and Eating Disorder Hope. Libby lives in the St. Louis area with her husband and two daughters. She enjoys spending time with her family, running, and watching movies.
References:
[1] https://www.jci.org/articles/view/18533
[2] http://www.amhc.org/1408-addictions/article/48342-biological-causes-of-addiction
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2715956/
[4] http://www.crchealth.com/addiction/drug-addiction-rehab/drug-addiction-rehab-2/home-2/biological_addiction/
[5] http://www.asam.org/quality-practice/definition-of-addiction
[6] http://www.mhmrcv.org/poc/view_doc.php?type=doc&id=58685&cn=1409
[7] https://www.nap.edu/read/5297/chapter/7#120
The opinions and views of our guest contributors are shared to provide a broad perspective of addictions. These are not necessarily the views of Addiction Hope, but an effort to offer discussion of various issues by different concerned individuals.
We at Addiction Hope understand that addictions result from a combination of environmental and genetic factors. If you or a loved one are suffering from an addiction, please know that there is hope for you, and seek immediate professional help.
Reviewed By: Jacquelyn Ekern, MS, LPC on March 25, 2017.
Published on AddictionHope.com