What is the link between heredity and alcohol addiction?

The link between heredity and alcohol addiction is strong and complex. Behaviour is often said to be 50% natural and 50% nurture. In alcoholism’s case, this may be true, as about 50% of your risk of addiction comes from your genes, which are passed on to us from our parents.

It’s far too reductive to say there’s such a thing as an ‘alcoholism gene.’ The Human Genome Project estimates we have 20-25000 genes. We all have two copies of each gene, one inherited from each parent.

Of these 20-25000 genes, only a few have been identified as having a role in developing or being protective against alcohol addiction – there is much we still don’t know about the human genome. However, some research, particularly in the field of epigenetics, has encouraging conclusions on how we might go about beating alcohol addiction.

 

Genes

ADH1B (alcohol dehydrogenase 1B) and ALDH2 (aldehyde dehydrogenase 2) are two genes that have been directly studied for their part in developing alcoholism. Both of them play a key role in breaking down alcohol by coding the enzymes in our liver that are responsible for breaking alcohol down. Having certain variants of these genes changes the way our bodies do this.

When we drink alcohol, the first step in metabolising it is converting it into a toxic substance called acetaldehyde. If you have a variation of ADH1B that lets your body do this more effectively, acetaldehyde builds up in your body more quickly, which causes facial flushing, nausea, and rapid heart rate. Everyone breaks down alcohol into acetaldehyde after drinking it, but people with this effective variant of ADH1B are less likely to become addicted to alcohol because the unpleasant effects from breaking it down happen much faster, and levels of acetaldehyde can get higher in the body.

The second step of breaking down alcohol is turning acetaldehyde into acetate in the body. Acetate is less harmful and feels less unpleasant.

If you have a less effective variant of ALDH2, acetaldehyde – the unpleasant compound – stays around longer before being turned into acetate – the less unpleasant compound. Again, this makes it less likely that you will develop an alcohol addiction, as having acetaldehyde present in your body for longer and at higher levels doesn’t feel good.

Studies in Japan found a certain variant of ALDH2, called ALDH2*2, was extremely protective against developing alcoholism. Out of 1300 alcoholics, not one was homozygous for ALDH2*2 – that means inheriting identical copies of that gene from their mother and father. From a sample of 1300 people, 118 of them would usually have this genetic profile – but none of them had it.

Other genes are associated with alcohol addiction – but we don’t yet know precisely how. These include GABRA2, CHRM2, KCNJ6, and AUTS2.

GABRA2, for instance, is part of the GABA receptor gene cluster—this means it’s responsible for coding for the neurotransmitter GABA. Alcohol’s effect on GABA plays a huge part in how it affects our brain chemistry, so understandably, having a variant of the GABRA2 gene can affect how alcohol feels to us subjectively and our individual risk of addiction.

As with many other genes, we aren’t sure yet exactly how this works. However, what is clear is that having different variants of genes alters how alcohol interacts with our body, how we experience it, and how likely it is to be habit-forming.

Can gene therapy be used as alcoholism treatment?

There has been recent research using gene therapy to treat Parkinson’s disease – and as a side effect, scientists found it also reduced alcohol consumption by 90%.

The study implanted a specific type of molecule that induces cell growth in the brain, which affects the dopamine reward system.

However, this study was on primates, had a very small sample size, and it is not yet known if this would be safe or effective for humans.

Environment

Genes account for about 50% of your risk for developing alcohol addiction, but inheriting a genetic profile with an increased risk of developing alcoholism doesn’t mean you definitely will. This is where environmental factors come into play.

Unfortunately, if you inherited a genetic susceptibility to addiction, it runs in the family. This increases (but far from guarantees) the risk that you grew up in an environment where a family member was in active addiction. This environment also raises the likelihood of developing an addiction of your own due to Adverse Childhood Events (ACEs).

Adverse Childhood Events are things that happen in your early life that can cause difficulties later – one of them is having a family member who is in active addiction, which can bring stress, chaos and financial difficulties into the home.

The more ACEs you have, and the more severe they are, the higher the risk for mental health problems and addiction later on. ACEs also reduce resilience.

Epigenetics

Epigenetics is the bridge between genes and the environment.

Genes can be ‘switched on or off’ – that is, expressed or not expressed, depending on environmental factors. Epigenetic changes can be temporary or long-lasting.

For instance, people may start drinking because they have a gene that causes them to feel anxiety more strongly. Via epigenetics, overconsuming alcohol tweaks the volume control of your genes, and this can turn into dependence.

We can’t change our DNA. However, our behaviours and environment can change how our genes express themselves. While we may not have had control over our environment when we were young, we can make changes to it now.

Getting alcohol help – change your environment

Alcoholism rehab and alcohol detox let you leave the environment where addiction has taken hold and allow you to develop healthier behaviours.

Sustained alcohol abuse rewires the brain – seeking out alcohol addiction help can help you take this rewiring into your own hands and give you the right environment to beat alcohol addiction. If you’re ready for that first step, contact us today.