There is no simple answer to the questions, “What causes addiction?” and “How do addictions start?” Addictive behaviors involve a complex interaction of genetic and environmental factors that can vary across different individuals.
Research that examines the relationship between heredity (genetic factors) and addictive behavior typically uses family studies that can include investigations of addictive behaviors in parents and children, identical twins, fraternal twins, adopted children, and siblings, to determine the genetic contribution to addictive behavior.
There have been numerous genes associated with addictive behaviors of all types as a result of the studies. However, not everyone who has a particular kind of addiction shares the same genes. Also, many people who share genes that are identified with addictive behaviors do not develop addictions.
There is no definite conclusion regarding the percentage of nearly any behavior that can be attributed to genetic factors. The best conclusion is that, like all behaviors, addictive behaviors share some genetic associations. Genes may account for some of the causes of addiction, but genes need to interact with environmental factors.
Researchers and clinicians do not think of the relationship between genetics (heredity) and addictive behaviors as being causal. Instead, heredity (genetics) is considered to be a significant risk factor for the development of addictive behavior.
A risk factor represents some condition or situation that can increase the probability that someone may develop some type of trait, disorder, or disease. Risk factors are not considered to be direct causes; they only increase the probability (risk) that one might develop a particular condition.
Heredity is a known risk factor in the development of addictive behavior. The children of people who have been diagnosed with a substance use disorder are far more likely to develop one themselves than children born to parents who have no history of substance abuse.
However, not every child born to parents with a history of substance abuse will develop an addiction and many children who have parents who did not abuse substances develop substance use disorders.
Even in identical twins who share 100 percent of their genetic material, one twin may have a substance use disorder, and the other twin will not.
When averaging the research studies, it appears that if one identical twin is diagnosed with a substance use disorder, there is about a 50 percent chance that the other twin will also be diagnosed with one.
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The other important thing to understand about the relationship between heredity and behavior is that a person’s genes cannot act in isolation.
In order for your genes to express themselves as behaviors, they must have some type of environmental stimulation. Thus, it would be grossly incorrect to state that your substance use disorder was caused by your genetic makeup.
The American Psychiatric Association (APA) has listed some of the more prevalent risk factors that are associated with the development of different types of addictive behaviors. These include:
While much of the early research regarding the causes of addictive behaviors focused on risk factors, some of the more recent research has looked at factors that can shield or protect someone from developing an addiction.
It stands to reason that if genetics (heredity) can be a significant risk factor for the development of addictive behaviors, there must also be a genetic component that is associated with being relatively resistant to developing addictive behaviors.
If there are environmental risk factors that can increase the probability of developing an addiction, it stands to reason that there must also be environmental factors that can make one more resistant to developing addictive behaviors. These factors are typically referred to as protective factors.
Some protective factors include:
For instance, healthy afterschool activities for children have been demonstrated to reduce vulnerability to addiction. Even access to exercise can discourage drug-seeking behavior.
We all have certain psychological and biological characteristics and experiences that can make us more vulnerable or resistant to developing a substance use disorder.
Every one of these biological, psychological, and experiential risk factors and protective factors will exist through multiple different levels. These factors influence one another.
Factors that lead to an increased risk of developing addictive behavior are multifaceted, interact over numerous contexts, and will vary significantly from person to person.
Two attributes that are commonly associated with a significantly increased risk to develop some type of addictive behavior are impulsivity and sensation seeking. As it turns out, both of these attributes are also considered to have a high genetic component to their manifestation in individuals.
There are very few treatments that are designed to address these issues in people with substance use disorders. One of the treatments is a therapeutic technique known as contingency management.
In this technique, positive reinforcements for not acting impulsively are used to change impulsive behaviors.
Even though these qualities are considered to have high hereditary components to them, the most effective treatments are designed to change environmental conditions. This highlights the idea that heredity and environmental experience cannot be separated.
Although it is clear that genetics plays a part in the possibility of developing addictive behaviors, they are not causes of addiction. Even if you have a family history of addiction, you are not destined to struggle with addiction. The development of a substance use disorder is a result of the complex, numerous factors.
The treatment of substance use disorders focuses on altering environmental factors and changing beliefs and attitudes. People who have significant protective factors may also have significant resilience to the development of an addiction. Some protective factors, like strong levels of positive social support, can be developed by altering a person’s environment.
(June 2016) Genetics of addiction: future focus on gene × environment interaction?. Journal of Studies on Alcohol and Drugs. Retrieved April 2019 from https://www.ncbi.nlm.nih.gov/pubmed/27588524
Risk Factors. World Health Organization. Retrieved April 2019 from https://www.who.int/substance_abuse/en/
Risk & Protective Factors. Youth.gov. Retrieved April 2019 from https://youth.gov/youth-topics/youth-mental-health/risk-and-protective-factors-youth
(December 2010) Resilience: A definition in context. Australian Community Psychologist, Retrieved April 2019 from http://groups.psychology.org.au/Assets/Files/ACP-1-2010.pdf#page=30
(July 2016) Personalizing substance use treatment based on pre-treatment impulsivity and sensation seeking: A review. Drug and Alcohol Dependence. Retrieved April 2019 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5037032/
(January 2018) Contingency Management Interventions/Motivational Incentives (Alcohol, Stimulants, Opioids, Marijuana, Nicotine). National Institute on Drug Abuse. Retrieved April 2019 from https://www.drugabuse.gov/publications/principles-drug-addiction-treatment-research-based-guide-third-edition/evidence-based-approaches-to-drug-addiction-treatment/behavioral-0