The Genetics of Mental Illness

Editor’s note: Pending an FDA decision, 23andMe no longer offers new customers access to health reports referred to in this post. Customers who received their health information prior to November 22, 2013 will still be able to see their health reports, but those who purchased after that time will only have access to ancestry information as well as access to their uninterpreted raw data. These new customers may receive health reports in the future dependent on FDA marketing authorization.

Researchers have long believed that genetics put some people at higher risk for mental illness than others, but exactly which genes are involved has remained a mystery. Even very large studies have come up with relatively few insights into the genetics of mental illness.

But a study published last week in The Lancet is shedding some light on the connection between genetics and mental illness. The study is the largest mental illness study done to date, and used genetic data from over 60,000 people of European ancestry.

The scientists, led by Dr. Jordan Smoller from the Massachusetts General Hospital in Boston, looked at five different forms of mental illness: autism spectrum disorder, bipolar disorder, attention deficit-hyperactivity disorder, major depression disorder, and schizophrenia. They found four different genetic associations with mental illness in general, and surprisingly they discovered that three of the four associations were involved in all five conditions. This means that the same genetic variants involved in depression may also be involved in schizophrenia.  This genetic similarity between different forms of mental illness was suspected from previous studies in which twins would have different forms of mental illness.

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Another interesting aspect of this new study was the importance of calcium channels. Calcium is important for muscle contractions and heart beats, and calcium channels are gates that let calcium in and out of our cells. Two of the four genetic variants that the researchers found occur in genes that encode these calcium channels, suggesting that calcium channels may also be important for mental health.

Sometimes research discoveries seem too removed from our day-to-day life to matter.  Yet this new insight into calcium channels could lead to new treatments, and new treatments would mean good news for millions.  During the course of this year, it is estimated that one in ten of us will suffer from a mood disorder, such as depression or bipolar disorder.  If it’s not you, it may be someone you know.  That makes this study pretty exciting for us all.

This graph shows the prevalence of different forms of mental illness in US adults in any given year. Statistics are from NIMH.

 SNPwatch gives you the latest news about research linking various traits and conditions to individual genetic variations. These studies are exciting because they offer a glimpse into how genetics may affect our bodies and health; but in most cases, more work is needed before this research can provide information of value to individuals. For that reason it is important to remember that like all information we provide, the studies we describe in SNPwatch are for research and educational purposes only. SNPwatch is not intended to be a substitute for professional medical advice; you should always seek the advice of your physician or other appropriate healthcare professional with any questions you may have regarding diagnosis, cure, treatment or prevention of any disease or other medical condition.