There’s nothing particularly new about the New Year from a biological perspective. We have mechanisms inside cells that keep time on a day-to-day basis, but certainly nothing to keep track of the rhythm of the year. Our livers may have felt the consequences of celebrating the passage of 2009, but our DNA hardly records the passage of time at all.
Our brains, however, make a big deal about the passage of years. Right around mid-December, we start seeing just about every organization publishing their list of the the top 10 moments in whatever they happen to be interested in – the top 10 harpsichord riffs of 2009, the top 10 videos in big game fishing, the decade’s best basket-weaver.
Science is no exception, and it’s with a certain amount of pride that I say that my own supervisor, Dr. Michael Meaney, with Dr. Gustavo Turecki from here at the Douglas, are the recipients of Radio-Canada’s awards for Scientist of the Year for 2009. Working in collaboration with Dr. Meaney, Dr. Turecki, and Dr. Moshe Szyf at McGill University, post-doctoral fellow Patrick McGowan showed that DNA from suicide victims who were abused as children is qualitatively different from those who were not abused.
This finding got a great deal of media attention when it was published almost a year ago, and rightfully so. It is a tremendously important finding, even if certain laypeople think that the results are “obvious.” I agree to a certain extent – it is, in fact, obvious that child abuse is wrong and has detrimental effects on a person that can last their whole lives. Hence “abuse.”
What isn’t obvious is how the effects of abuse can persist through a person’s life. There is tremendous stigma regarding mental health issues and a certain attitude that sufferers should “get over it,” or that they can somehow think themselves into health. Without hard evidence that there are biological underpinnings for mental disorders, it is very difficult to defeat a misconception of this nature.
In many ways, this is what the study shows. I have written about epigenetics before, and how our environments can “talk” to our DNA, and program it to do certain things. This study is very much in the same vein. The sequence of our DNA doesn’t change through our lives, but the way it is organized within our cells can change as a result of our environments, and this affects the way our DNA functions. It’s a code for making proteins, the workhorses of our cells, and if it’s organized in such a way that a part of the code can’t be read, then that protein doesn’t get made and the work doesn’t get done.
A key mechanism for the way this happens is by DNA methylation. Specific sites within DNA can be chemically modified so that what we call a methyl group gets attached. This methyl group is a sign for the cell to organize the DNA such that the bit with the methyl groups doesn’t get read anymore.
Dr. McGowan’s research used tissue from the Douglas Institute Brain Bank to show that there were different patterns of DNA methylation in suicide victims who were abused as children compared to suicide victims that were not. A certain gene which is very important in controlling stress and anxiety was found to be more heavily methylated in the brains of abused suicide victims. This would result in reduced amounts of the protein, and a reduced ability to control anxiety and stress.
This is important for numerous reasons, but in my opinion the most important one is that legislators and health care professionals can use this as an example of the biological phenomena that underlie mental health issues. These are not things we can think our way out of, or will ourselves to change, but rather serious biological issues that, in many ways, are almost undefined by science.
Despite all the New Years’ celebrations since we started investigating mental disorders from a biological perspective, we have a lot of work to do. A great deal of that work is research, but it’s clear that we also have a lot to do in terms of convincing the public that biology, rather than “mind,” is what underlies mental disorders; and that the development of treatment programs that address the biology of mental health are of paramount importance. No one asks a patient to “just get over” multiple sclerosis, or think themselves free of epilepsy. Other disorders affecting the biology of our brains should be no different.
For more on epigenetics, I am shamelessly plugging a video of myself giving a talk on epigenetic programming by the environment at a recent McGill conference. It’s aimed at a scientific audience rather than the layperson, but I encourage you to have a look. You know where to find me if you have questions.
Posted in General science.Posted on 19 Jan 2010