Over on the AllPsych blog, I just wrote an article about how different psychiatric disorders can share the same genes. One of the studies I mentioned in the article found that there was significant genetic overlap between genes for ADHD and genes for depression.

Here, I want to go a little more in-depth on the genetics of ADHD.

DNAAs it turns out, depression isn’t the only disorder that shares genes with ADHD. For example, research has suggested that ADHD also has genetic links to autism, substance use and OCD. In fact, pick a psychiatric disorder out of a hat and you have a decent chance that there’s a study suggesting some genetic overlap between that disorder and ADHD.

That’s why people with ADHD, in addition to having a family history of ADHD, often have a family history of other mental health conditions too. And it plays a part in why people with ADHD frequently have other disorders as well.

You’ve likely heard before that ADHD is heritable. If you have a child or a parent with ADHD, you’re more likely to have ADHD yourself – hence the common scenario where an unsuspecting parent takes their kid in to be evaluated for ADHD and ends up getting diagnosed themselves.

How heritable is ADHD though, exactly? Give me some numbers!

It’s tough to say for sure, since different studies end up with somewhat different figures. That said, a massive study of 59,514 Swedish twins (think about that for a second) estimated that the heritability of ADHD is about 88 percent in children and 72 percent in adults. In other words, well more than half of whether or not you have ADHD is apparently just down to your genes.

That’s why, as you’re learning more about your diagnosis, it can be interesting to take a look for signs of undiagnosed ADHD in your family tree. These signs can range from impulse control problems (substance use, gambling, trouble managing money, issues with emotional regulation) to unexplained underachievement to a generally chaotic lifestyle.

Remembering that ADHD is in your genes can be helpful in popping once and for all any lies you might be tempted to tell yourself about whether your symptoms are your fault or whether you could get rid of your ADHD simply by “trying harder.”

That said, when we think about how our genes shape who we are, there’s always an interesting paradox: although our genes influence the course of our life, they are not our destiny. Your genes may have made a major contribution to you having ADHD, but you still have a say in what comes next: you’re free to learn more about ADHD and figure out how to manage it. You can’t make ADHD or your genes go away, but you can find a way of structuring your life that accommodates your symptoms and makes you happy.

Image: Flickr/Karl-Ludwig Poggemann