What role do genetics play in how much your child will drink?

Some of the saddest parents I meet are those Mums and Dads who approach me after a presentation desperate for help who simply don't understand where they went wrong with their 'out-of-control' teen! These are good parents who usually have a number of children, some of whom have already got to the other side of adolescence without too many problems, and all of a sudden they have found themselves with a son or daughter who is completely different to the rest of the family. They just don't understand why their son or daughter is acting out to such a great extent, particularly when it comes to drinking alcohol.

What really confuses them is that they believe that their parenting style hasn't changed – they are doing exactly the same thing with this child as they did with the others – why then are they getting such a different result? Sadly, my presentation to parents doesn't help them much, in fact it usually makes it worse, because in it I stress the importance of parenting styles and discuss the growing amount of evidence that shows how you parent has a major influence on their future drinking behaviour.

At this point it is important to acknowledge that in reality it is almost impossible for parents to 'parent' each of their children in exactly the same way. There is always going to be differences in what you do and how you do it with each of your children. For example, there is research that shows, where siblings have been asked to say who their mother and father favour, that mothers do tend to a show a preference for their first-born son, but fathers often dote on their youngest daughters. It sounds like a huge generalisation but there is also evidence to suggest that parents will often be drawn to the child who is easiest to get along with — or the child that shares similar traits to them, e.g., mum will have a special bond with her sensitive, arty son, while dad lavishes attention on his sporty daughter.

That said, there must be something else happening here and that's where a recent Dutch study may start to provide some of the answers. To my knowledge this is a world-first, a study that not only looked at the influence of parenting style on future drinking behaviour, but also what role genetics may play?

The researchers looked at almost 600 young men each year over a six year period and divided them into one of three groups – 'light', 'moderate' and 'heavy' drinkers. They conducted saliva samples to enable genetic testing and identified different genotypes that could result in different neural responses to alcohol or motivations to drink (these were identified as 'risk' and 'non-risk' genotypes). They also looked at parenting styles and examined whether parents had set specific rules regarding alcohol.

The paper makes for an interesting read (the reference is included at the end of this entry) but the basic findings were as follows:

• 'light drinkers' - often 'non-risk' genotype and reported stricter parental rules
• 'heavy drinkers' who carried the 'risk' genotype were largely affected by parental rules – more rules, lower levels of alcohol use
• however, heavy drinkers who carried the 'non-risk' genotype weren't so influenced by rules

What they found in this groundbreaking study was that strict parental rules certainly appeared to prevent most young people from drinking to excess (no surprise there!). However, they found it wasn't always that simple and "the interaction of specific genes and parental rules may determine whether a teen will have alcohol-related problems in the future." The group of young people who carry the 'non risk' genotype who do drink to excess are obviously a group that we will have to try to keep safer in a different way – if rules and consequences aren't going to work effectively, we're going to have to develop other strategies to help parents.

What I love about this study is that we can finally say to a parent who is having a problem with just that one teen – you are not to blame. It may not have anything to do with your parenting, instead, it may be due to genetic factors - something that is totally out of your control!  That certainly doesn't mean you roll over and give up but this study does start to begin to provide somewhat of an answer to a parent who is really struggling with an adolescent that is difficult to parent.

Reference: Van der Zwaluw, C.S., Otten, R., Kleinjan, M., & Engels, R.C. (2014). Different trajectories of adolescent alcohol use: Testing gene–environment interactions. Alcoholism: Clinical and Experimental Research, doi: 10.1111/acer.12291. (Epub ahead of print).