Is addiction really genetic?

My brother has been in and out of rehabs for years, and lately I've been researching addiction and trying to understand the science behind it. A lot of sites that I've found say that addiction is genetic, but the info is extremely generalized and surface level. I haven't found any specific information about how it's passed down or if there are any genetic markers for it. Obviously, if he's predisposed, then so am I.

I understand that it's more than just genetics and physiology, and that nature and nurture both play a role. I found a lot of good info about that here. I just want to know if you think that there is a specific gene tied to addiction that has yet to be found, or if it has nothing to do with genetics at all.
Having seen multi-generational alcoholism and near-alcoholism, with some exceptions, I must wonder if there's a set of genes / epigenetics that predisposes them.

( Like HLA complex, which may carry a cruel down-side to its advantages for some... )

Nature vs Nurture ? Well, both. Also, anecdotal-only, I've seen a lot of folk who really, really enjoyed their drink when young, excessive imbibing became habitual, then trapped them as their liver function declined with age or illness...

jim mcnamara

Alcoholism is a kind of addiction. Look into that. The research is good because it has been better funded.

If you want science and not promotional websites, consider a google search of NIH, the (US) National Institutes of Health. One of its divisions is devoted to alcoholism studies: NIAAA: National Institute on Alcohol Abuse and Alcoholism. Alcohol abuse is a massive public health issue. And yes there is evidence of genetic association with alcoholism, however factors leading to alcoholism are many and not all genetic.

Review article:

do a crtl/f page text search on the word chromosome when you open the link. Humans have pairs of chromosomes, numbered 1...22 plus two sex chromosomes
Chromosome #1 and #7 are where certain genes (alleles) live, and some of them are reported to increase the likelihood of alcoholism. And some other related problems.

And no. Just because your brother has addiction problems does not guarantee that you will. Which is what this paper says in part about that aspect of alcoholism.

This google search will give you tons of reading material.
nih: genetics of alcoholism
NIH: filters out everything except research and public white papers, kind of like news releases meant for non-science types.

Too many sites from regular searches are really disguised promotions for rehabilitation centers and counseling. While this may help some patients, you want real research.

NIH does not allow promotional content in its PUBMed research index.

If this stuff you see is too technical you can change your search a bit to:
nih:causes of alcoholism

Most of the addiction research is under the realm of Psychiatry. Here is one paper on heritability of addiction, it discusses the fact that addiction is a neuroadaptive change in patients. Kind of like Pavlov's dog if you know about that. The reason is that addiction is a complex of behaviors that become ingrained. So it is harder to sort out genetics.
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I just want to know if you think that there is a specific gene tied to addiction
There is good evidence to suggest that individuals susceptibilities to addiction is influenced both by the their genes and their environment. Studies of families suggest that approximately half of the risk that an individual will develop an addiction, with environmental and other factors accounting for the other half of the risk (

Susceptibility to addiction is what is known as a complex (or polygenic) trait. Unlike the simpler Mendelian traits that most of us learn about in our introductory biology classes, complex traits are controlled by a number of different genes which each exert a small influence on the trait. In addition, complex traits are often influenced substantially by environmental and other non-genetic factors. Other examples of complex traits include height, intelligence, and risk of autism. Because complex traits are controlled by a number of genes, there is not one risk gene that we can examine to judge an individual's genetic risk of addiction. There have been some efforts to develop polygenic risk scores (e.g. see, which combine information about multiple genes, but so far these genetic risk scores are not very good at predicting risk of addiction.
Perhaps the most important genetic discovery in the last few years is the finding that the genetic research conducted over the last 50 years has been based on flawed beliefs. The fact that this had essentially wasted billions even prompted some to call for the whole area to be de-funded but the allure of finding simple straightforward cause/ effect relationships between biology and mental health has kept the money flowing. Of course everything about being human will be influenced by genes at some level so the question as to whether addictions are genetic is not particularly useful, what we need to know if whether trying to understand addiction at the level of the gene is useful. So far, the preferential position given in funding to genetics and other biological explanations for decades has given us nothing of use, this is in marked contrast to physical medicine.
I would suggest you do a search on genetics and addiction adding the word critique, you will find lots of work about why this whole idea is problematic, perhaps the most obvious being that addiction is clearly not a single discrete problem, the fact that the US tends to treat them all in the same way doesn't make it one nor does the confused legal position. There will be certain people who have traits that in a given context may lead to drug use, within this group there will be people who find a particular drug might fill a particular need, coffee for example (there was an attempt to make coffee illegal at one time), the drug may induce neurological adaptations and or the effect might lead to compulsive use, but none of these things occur in a consistent or predictable pattern.

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