Genetics And Addiction: Is Drug Addiction Genetic?

Addiction is considered a disorder affecting an individual’s brain because it brings about functional changes involving brain circuits that are responsible for managing stress, self-control, and feelings of reward. The changes can last long even after an individual stops using drugs. The National Institute on Drug Abuse says that addiction, like many other diseases, it disrupts the normal functioning of body organs.  The chances of being addicted differ from an individual to another, and no single factor can determine whether somebody will be addicted to alcohol and drugs. Generally speaking, the more risk factors an individual has, the higher the possibility that using drugs will result in addiction. On the flip side, protective factors reduce an individual’s risk of being addicted. The risks and protective factors can be biological or environmental.

Many studies have been examining the link between addiction and genes and when scientists are looking for “addiction genes”, they are primarily looking for the differences in biological composition that make an individual be less or more susceptible to addition. Some people may have difficulty quitting drugs or alcohol once they start, others may develop severe withdrawal symptoms when they try to stop consuming the substances.

An individual who grows up in a household in which substance abuse was common may have his or her attitude toward alcohol and drugs influenced by the circumstance. In addition, an unstable childhood environment may raise an individual’s risk for addiction. Children born of addicts have 8 times chances of developing addiction than those that aren’t.

It is also likely that an individual will be addicted to various drugs if their family history is associated with addiction and this is known as cross-addiction. At least, a family member abuses drugs or alcohol, then an individual from that family has an increased probability of being addicted to drugs like cocaine, marijuana, opioids, or even alcohol. Cross-addiction arises because the process of addiction works in the same area of a person’s brain. So if a person’s brain is wired in such a way that he or she is predisposed to a particular addiction, it may be that the individual will be predisposed to any addiction. One addiction can contribute to other forms of addictions. Similarly, being addicted to one drug could make a person relapse on other drugs.

Biological Factors Associated with the Risk of Addiction

Various biological factors affect an individual’s risks of being addicted and they include genes, gender, ethnicity, and stage of development. Scientists project that genes account for 50 percent of an individual’s risk of addiction.

Environmental factors can also impact an individual’s gene expression. As a child’s brain develops, the experience he or she goes through cuts back excess neural connection while at the same time strengthening the ones that tend to be used more often. Scientists believe that the process causes changes in the volume of the child’s gray matter. It contributes to a gradual reduction in the volume of gray matter in the child as he or she grows to be a teenager or adult.

Environmental forces affect how the connections thrive and wither meaning that depending on the effects of environmental factors, you may have some neural connections becoming strong and others weakening. The brain circuits emerging from this process become more efficient. The process of neural connection occurring when the brain is maturing affects the individual in two ways. It can cause both negative and positive effects. Think of it this way, the environment works like an artist who makes a sculpture by chipping or flaking away excess marble. If an artist is not up to par in his or her skills, they will produce bad art and so is an environment having negative factors such as bullying, drugs, sleep deprivation, or malnutrition. Such environment can result in efficient, yet potentially disastrous circuits that negatively affect the well-being of an individual.

Research on the Role of Genetic Factors in Addiction

Studies have indicated that addiction occurs 50 percent due to the predisposition of the genetic component and 50 percent because of poor coping skills. In one study that involved 861 identical or matching twin pairs as well as 653 non-identical or fraternal twin pairs, it found out that when one identical twin became addicted to alcohol, there was a high possibility of the other twin to become addicted too. On the other hand, when one fraternal or non-identical twin became addicted to alcohol, it was not necessarily possible for the other twin to be addicted. Based on variations examined between the non-identical and identical twins, it was found out that about 50 to 60 percent of addiction arises from genetic factors. The remaining 50 percent of addiction arise from environmental factors that bring about poor coping skills like an inability to deal with uncomfortable emotions or stress.

Determining Addiction Genes

Most of the genes that are associated with addiction have been identified using animal models particular research done using mice. The reward pathway includes the genes that take part in the circuitry, function same way in an animal like mice as it functions in a human being. Studies done using mice have been leading the way in helping identify genes linked to addiction.  When scientists find a gene linked to addiction using model organisms like mice or fruit flies, they go ahead to identify a similar gene in humans. This is done by looking for DNA sequences that are similar in both humans and mice. Some of the genes that were identified in mice and are believed to play a role in determining an individual’s risk of being an addict are:

  • People addicted to cocaine or alcohol have in common the A1 allele in DRD2dopamine receptor gene
  • Mice that lack Cnr1 cannabinoid receptor gene tend to respond less to morphine
  • Miceexpressing more of the Mpdz gene tend to have less harsh withdrawal symptoms from barbiturates and other sedative-hypnotic drugs
  • Mice without serotonin receptor gene Htr1b tend to be more attracted to substances like alcohol and cocaine
  • Mice having reduced amounts of neuropeptide Y consume excess alcohol while the ones with increased levels abstain.
  • Mice having a defective genePer2 consumes alcohol three times more than normal
  • Fruit flies that have been mutated so that they don’t produce tyramine tend to remain sedate despite consuming repeated cocaine doses
  • Alcoholism is quite rare in individuals who have two copies of gene ALDH*2 variation
  • People who don’t smoke tend to carry a CYP2A6 gene’s protective allele than those that smoke, which makes them experience symptoms like dizziness and nausea whenever they smoke
  • Mice that lack the gene Creb shows fewer chances of being dependent on morphine.

How Addiction Runs in Families

Addiction is linked to genes, a hereditary component meaning it often occurs in families. A parent can pass “the ability to get addicted” to a child through genes. Researchers conduct studies in large families to find out the genes that could be making members of the families be vulnerable to addiction. The scientists begin looking at the DNA sequences and comparing the ones of family members having an addiction with the ones of family members not addicted. The researchers look for the DNA pieces shared among addicted individuals and those that are less common in people not affected. Something to mention here is that, since humans have varied and complex lives, the researchers use animal models to help them learn in depth about addiction genetics.

Breaking The Cycle

Although addiction has a strong link to genetics, it doesn’t make it your fate. Try to develop coping skills that will be a legacy you convey to your kids. Do not let genes dictate the fate of your children. You can help the kids lead a happy life by teaching them about healthy coping skills. Be a good example by allowing the kids to learn that they have an option regardless of the risk your family history puts on their shoulders regarding the possibility of developing an addiction.

If you think that there is a genetic propensity to addiction in your family, it is important you avoid using drugs or consuming alcohol. If you are already addicted or struggling with drug use, seeking treatment can help free you of addiction and start a life of sobriety.