Uticopa Blog

A new study has found that genetics not only has a major role in depression, but it actually plays a bigger role in depression for women than it does for men. Researchers often study identical twins raised apart because this is the best way to find out whether a disorder is caused primarily by genes or environmental factors. Some recent studies, when analysed together, found that genetic factors accounted for 42% of depression in women, against only 29% for men.

Certainly, most of us have noticed in everyday life that women tend to have more mood swings than men.  In the past this has always been put down to the fact that women have different types of brain activity than men. Men’s brains have two distinct sides, favouring concentration on one particular topic at a time. Maybe this is why women have found that it’s not a good idea to interrupt a man when he is concentrating hard on a project. Conversely, women’s brains tend to be more interweaved, continual cross-referencing happening all the time. Maybe this occurred over the centuries due to a woman’s role in needing to ‘rock the baby and stir the custard at the same time’!

But, what have genes to do with depression anyway?  Depression is caused by sad events in your life, isn’t it? 

Although it is true that environmental factors do play a part in depressive illness, researchers have also discovered a mutant gene that starves the brain of serotonin, a mood-regulating chemical messenger.  The gene was found to be ten times more prevalent in depressed patients than in non-sufferers. Patients with the mutation failed to respond well to commonly prescribed anti-depressants, which work via serotonin.

There were also cases where such patients had a family history of mental illness or substance abuse, some being suicidal. This suggests that the mutant gene somehow stops the body from responding to standard medications.

If confirmed, this discovery could lead to a future genetic test to see which people are more vulnerable to depression. There could then be a way to predict which patients might respond best to serotonin-selective anti-depressants.

Major depression is now thought to be 40-70 percent heritable, but likely involves an interaction of several genes with environmental events.

Could the above differences in male/female brain cell-behaviour form part of the reason why women’s brains inherit the depression gene more than men’s? Certainly, this interesting subject needs more research.

But, in the meantime, whatever your gender and whatever the cause of your illness, remember that clinical depression is a serious illness. It is very important to get professional help and advice from a mental health therapist and from your doctor.

References

In addition to grants from NIMH and NHLBI, the above study on twins was also funded by the Human Frontiers Science Program and the Canadian Institute of Health Research. 
 
Kenneth S. Kendler, M.D., Margaret Gatz, Ph.D., Charles O. Gardner, Ph.D., and Nancy L. Pedersen, Ph.D. Swedish National Twin Study of Lifetime Major Depression. American Journal of Psychiatry, January 2006, vol. 163