According to numerous studies, addiction has a 50% genetic predisposition, with environment and poor coping skills contributing to the other 50%. The children of addictions are 8 times more likely to develop some type of addiction. Around 100 million people in America have at least one alcoholic drink daily, and approximately 18 million people are alcoholics. In addition, 23 million people admitted to using an illicit drug during the last year. Drug addiction is a serious problem with a major genetic component.
The Research Studies
In one study involving 861 pairs of identical twins and 653 pairs of fraternal twins, researchers confirmed the genetic component of addiction. When one twin was addicted to alcohol, the other twin had a high probability of developing addiction. However, when one non-identical twin became addicted to alcohol, the other twin did not usually develop the addiction. In another study involving almost 2,000 twins, researchers found a strong genetic link for cocaine addiction. The concordance for cocaine use was 54% for identical twins and 42% for fraternal twins.
In a study involving 231 people diagnosed with alcohol or drug addiction, and 61 persons who did not have an addiction, researchers analyzed first-degree relatives, including siblings, children, and parents. They found that the child of a person with addiction had an 8 times higher chance of developing addiction.
Genes for Addiction
Everyone has the potential for addiction because of the reward system in the brain. Certain brain chemicals are activated when drugs are used. If you have a low genetic predisposition for addiction, you still may become addicted. However, there is much lower risk for addiction than for someone who has a genetic predisposition.
Variations in a particular gene can occur from one person to the next, which allow for hair color, eye color, and height. Genes come from parents, and the risk of developing addiction is inherited as well. Another factor that affects addiction is childhood trauma. Severe stress early in live increases the risk for drug addiction later in life. Some genes are linked to serotonin transportation, and these affect how a person handles stress. Chronic stress and addiction can induce similar epigenetic changes in stress systems, as well as those associated with pleasure.
According to the National Institute on Drug Abuse (NIDA), there are other factors that contribute to development of addiction. These include:
- The neighborhood or place of residence.
- The age a person begins drinking or using drugs.
- A person’s friends.
- The availability of alcohol and/or drugs.
- The person’s gender.
- The presence of mental health issues.
Some diseases are caused by a single gene problem. With addiction, there is a polygenic issue, with many genes contributing to the condition. At present, 1,500 genes have been linked to addiction, which are further classified by neuroadaptations and continued exposure. The more mutation a person’s genes undergo, the greater their vulnerability to developing addiction. Heritable factors and adverse environmental exposures activate a genetic predisposition and increase a person’s risk for substance abuse. However, addiction is a complicated, integrated process affected by the individual pharmacological profiles of the drugs themselves, as well as various environmental factors.