Most families I meet did not think much about whether addiction runs in families until it showed up at their own kitchen table. A mother sits in my office and tells me about her son's third residential program, and then, almost as an afterthought, mentions that her father drank himself out of two jobs and her brother has not spoken to anyone in the family in years. She is asking whether her son was born with this. The honest answer is yes, partly, and the reasons are not as simple as most people assume.
Is addiction heritable?
Yes. Twin and family studies have shown for decades that a large share of the risk for addictive disease is inherited. What has been missing is a clear picture of which genes carry that risk and what they do. In March 2023, a team of more than 150 researchers led by Alexander Hatoum at Washington University in St. Louis published one of the largest genome-wide association studies (GWAS) of addiction in Nature Mental Health. They combined genetic data from more than 1 million people of European ancestry and over 92,000 people of African ancestry, drawn from studies of problematic alcohol use, problematic tobacco use, cannabis use disorder, and opioid use disorder.
In the European ancestry sample, the team found 19 independent genetic variants tied to a general addiction risk factor, meaning risk that is shared across substances rather than specific to one. They also found 47 variants tied to individual substances: 32 for tobacco, 9 for alcohol, 5 for cannabis, and 1 for opioids. The African ancestry sample was much smaller and yielded only one general variant, which tells us the field still has work to do before these findings apply equally to everyone.
What a SNP is, and what it is not
The variants in this study are single nucleotide polymorphisms, or SNPs. A SNP is a difference in a single letter of the genetic code at one position on a chromosome. They are common. Each of us carries millions of them, and most do nothing we can detect.
It helps to compare this with a condition like Down syndrome, which comes from an extra copy of an entire chromosome. That is a large, visible change with a predictable result. Addiction-risk SNPs are nothing like that. Most of them sit outside the parts of a gene that code for proteins, and they are thought to act by adjusting how much a nearby gene is switched on, in which cells, and at what times. Each one moves risk by a very small amount. Risk builds when many of them add up in the same person, and even then the genes raise the odds rather than decide the outcome. Stress, trauma, early exposure to substances, and the environment a person grows up in all act on that inherited starting point, which is the gene-plus-environment model my colleagues and I described in the Journal of Addiction Science in 2020.
The dopamine finding that matters most
For thirty years the public story of addiction has been a dopamine story, usually told as a matter of quantity: some people make too little, some substances flood the brain with too much. The Hatoum study points somewhere more specific. Several of the strongest signals shared across substances mapped to parts of the genome that regulate dopamine signaling. They included the gene PDE4B, which still stood out when the two ancestry groups were analyzed together, and a region near the dopamine D2 receptor gene (DRD2). The authors suggested that variation in the regulation of dopamine genes, rather than variation in the core dopamine genes themselves, is central to general addiction risk.
That can sound like a fine distinction, but in the clinic it changes the question. My interpretation is that for many people the problem is less about how much dopamine is available and more about how the signal is tuned, received, and turned off. A brain like that can feel flat on an ordinary day and then respond far too strongly when a drug arrives. This fits what Kenneth Blum, his colleagues, and I have written about as reward deficiency, and it is why I talk with patients about restoring balance in the reward system rather than simply chasing more dopamine.
Why rehab keeps missing the biology
Classic follow-up data going back to Hunt and colleagues in 1971 found that roughly two-thirds of people relapse within about three months of leaving treatment. In my experience, the figure for people who complete 30 to 60 days of residential care runs close to 70 percent, with most relapses coming in the first weeks and months after discharge.
Over the years I have called a number of the most exclusive residential programs in the country and asked what biological testing they do. None described genetic testing, hormone testing, neurotransmitter testing, a biomarker screen, or a full laboratory workup. Every one of them told me they perform a "comprehensive" neuropsychiatric evaluation, and none could tell me what that evaluation includes. I doubt findings like Hatoum's will reach the treatment industry's protocols any time soon.
Dr. Sean Orr describes addiction as a form of Brain Failure, an organ failing in the same sense that a heart or kidney fails. We would not treat heart failure without an echocardiogram and blood work. We should not treat a failing brain without looking at it either.
What a biological workup looks like at NGP
When someone comes to The Neurogenesis Project for addiction, depression, or anxiety that has not responded to treatment, we start by measuring. Depending on the person, that includes hormone and metabolic laboratory panels, neurotransmitter testing, and genetic addiction-risk testing, along with a custom neurocognitive MRI that includes diffusion tensor imaging (DTI), which shows the integrity of the brain's white matter wiring. No single test on that list makes a diagnosis. Genetic results in particular describe probability rather than destiny, so we read them alongside imaging, labs, cognitive findings, and the person's history.
From there we build a targeted plan through our Rescue From Rehab program, which pairs the medical side of care with neurocoaching and the emotional and spiritual support that every lasting recovery needs. Our aim is to shorten the time and the suffering for patients and their families, because the alternative is too often disability, lost work, lost family, isolation, and death. Readers who want more on the reward system can start with our earlier piece on reward deficiency syndrome.
What to do with this if addiction runs in your family
If addiction runs in your family, treat that history the way you would treat a family history of heart disease. Tell your doctor about it, tell your children about it at an age-appropriate time, and take early warning signs seriously. If someone you love has been through treatment more than once, ask the next program exactly what it will measure before it decides what to do. A family history is not a sentence. It is information, and it should shape care.
Dr. Orr and I will go deeper into these genetic findings on an upcoming episode of The Braincast. If you or a loved one is living with addictive disease, or with depression or anxiety that will not lift, call The Neurogenesis Project at (904) 877-1887. We are glad to talk with you about your situation over the phone.
Hero image: illustration created with AI image tools.
This article was drafted with the assistance of AI writing tools, then reviewed, edited, and approved by Dr. Drew W. Edwards, Ed.D., who holds full editorial responsibility for its content.
Sources:
Hatoum, A. S., Colbert, S. M. C., Johnson, E. C., et al. "Multivariate genome-wide association meta-analysis of over 1 million subjects identifies loci underlying multiple substance use disorders." Nature Mental Health. 2023;1(3):210-223. doi:10.1038/s44220-023-00034-y
Edwards, D., Roy, A. K. III, Boyett, B., et al., Blum, K. "Addiction by Any Other Name is Still Addiction: Embracing Molecular Neurogenetic/Epigenetic Basis of Reward Deficiency." Journal of Addiction Science. 2020;6(1):1-4. PMID: 32432229; PMCID: PMC7236379.
Hunt, W. A., Barnett, L. W., Branch, L. G. "Relapse rates in addiction programs." Journal of Clinical Psychology. 1971;27(4):455-456. PMID: 5115648.