The Genetics of Addiction
The Role of Family History
Addiction is due 50 percent to genetic predisposition and 50 percent to poor coping skills. This has been confirmed by numerous studies. One study looked at 861 identical twin pairs and 653 fraternal (non-identical) twin pairs. When one identical twin was addicted to alcohol, the other twin had a high probability of being addicted. But when one non-identical twin was addicted to alcohol, the other twin did not necessarily have an addiction. Based on the differences between the identical and non-identical twins, the study showed 50-60% of addiction is due to genetic factors.(1) Those numbers have been confirmed by other studies.(2)
The children of addicts are 8 times more likely to develop an addiction. One study looked at 231 people who were diagnosed with drug or alcohol addiction, and compared them to 61 people who did not have an addiction. Then it looked at the first-degree relatives (parents, siblings, or children) of those people. It discovered that if a parent has a drug or alcohol addiction, the child had an 8 times greater chance of developing an addiction.(3)
Why are there genes for addiction? We all have the genetic predisposition for addiction because there is an evolutionary advantage to that. When an animal eats a certain food that it likes, there is an advantage to associating pleasure with that food so that the animal will look for that food in the future. In other words the potential for addiction is hardwired into our brain. Everyone has eaten too much of their favorite food even though they knew it wasn't good for them.
Although everyone has the potential for addiction, some people are more predisposed to addiction than others. Some people drink alcoholically from the beginning. Other people start out as a moderate drinker and then become alcoholics later on. How does that happen?
Repeatedly abusing drugs or alcohol permanently rewires your brain. If you start out with a low genetic predisposition for addiction, you can still end up with an addiction. If you repeatedly abuse drugs or alcohol because of poor coping skills, then you'll permanently rewire your brain. Every time you abuse alcohol, you'll strengthen the wiring associated with drinking, and you'll chase that buzz even more. The more you chase the effect of alcohol, the greater your chance of eventually developing an addiction.
Your genes are not your destiny. The 50% of addiction that is caused by poor coping skills is where you can make a difference. Lots of people have come from addicted families but managed to overcome their family history and live happy lives. You can use this opportunity to change your life. (Reference: www.AddictionsAndRecovery.org)
What Is Your Family History?
Most people don't know their family history of addiction very well. Addiction is not the sort of thing that most families talk about. Not too long ago you could have a raging alcoholic in your family and nobody would talk about it. Or they would make some quaint remark like, "Oh he drinks a little too much." There was so little people could do about addiction before that there was no point in talking about it.
But now that you can do something about addiction, a family history is worth talking about. Once you stop using and tell your family that you're in recovery, that's often when they will tell you about the family secrets. That's when family members will sometimes come out of the closet and tell you their stories.
Let your coping skills be the legacy you pass on to your children. Don't let your genes be the only legacy you pass on to your children. Your children are more likely to have an addiction because of your addiction. But their genes don't have to be their destiny. You can help your children lead happy lives by teaching them healthy coping skills – by being an example with your recovery.
Is Addiction a Disease?
Addiction is like most major diseases. Consider heart disease, the leading cause of death in the developed world. It's partly due to genes and partly due to poor life style choices such as bad diet, lack of exercise, and smoking. The same is true for other common diseases like adult-onset diabetes. Many forms of cancers are due to a combination of genes and life style. But if your doctor said that you had diabetes or heart disease, you wouldn't think you were bad person. You would think, "What can I do to overcome this disease?" That is how you should approach addiction.
Addiction is not a weakness. The fact that addiction crosses all socio-economic boundaries confirms that addiction is a disease. People who don't know about addiction will tell you that you just need to be stronger to control your use. But if that was true then only unsuccessful people or unmotivated people would have an addiction, and yet 10% of high-functioning executives have an addiction.
If you think of addiction as a weakness, you'll paint yourself into a corner that you can't get out of. You'll focus on being stronger and trying to control your use, instead of treating addiction like a disease and focusing on stopping your use.
You can become addicted to any drug, if you have a family history of addiction. If at least one of your family members is addicted to alcohol, you have a greater chance of developing an addiction to any other drug. Cross addiction occurs because all addictions work in the same part of the brain. If your brain is wired so that you're predisposed to one addiction, then you're predisposed to all addictions.
This is especially important for women who may come from alcoholic families, but who often develop addictions that go undetected, like addictions to tranquilizers, pain relievers, or eating disorders.
One addiction can lead to other addictions, and one drug can make you relapse on another drug. That's one of the consequences of a brain that's wired for addiction. Suppose you're addicted to cocaine. If you want to stop using cocaine then you have to stop using all addictive drugs including alcohol and marijuana. You may never have had a problem with either of them, but if you continue to use alcohol or marijuana, even casually, they'll eventually lead you back to your drug of choice. Recovery requires total abstinence.
How does cross addiction cause relapse:
- All addictions work in the same part of the brain. Addiction is addiction is addiction. Therefore one drug can lead you back to any other drug.
- Even moderate drinking or smoking marijuana lowers your inhibitions, which makes it harder for you to make the right choices.
- If you stop using your drug of choice but continue to use alcohol or marijuana, you're saying that you don't want to learn new coping skills and that you don't want to change your life. You're saying that you want to continue to rely on drugs or alcohol to escape, relax, and reward yourself. But if you don't learn those new skills, then you won't have changed, and your addiction will catch up with you all over again.
1) Prescott, C. A., & Kendler, K. S., Genetic and environmental contributions to alcohol abuse and dependence in a population-based sample of male twins. Am J Psychiatry, 1999. 156(1): p. 34-40.
2) Enoch, M. A., & Goldman, D., The genetics of alcoholism and alcohol abuse. Curr Psychiatry Rep, 2001. 3(2): p. 144-51.
3) Merikangas, K. R., Stolar, M., Stevens, D. E., Goulet, J., et al., Familial transmission of substance use disorders. Arch Gen Psychiatry, 1998. 55(11): p. 973-9.