Scientists have found through mice that a chronically stressed father may pass on depression and anxiety to their children.
Clinical depression is a common mental illness; approximately 19 million Americans are diagnosed annually. It is also responsible for approximately half of the suicides that occur in the US.
Scientists and doctors agree that depression and other stress-related disorders occur through a combination of inherited and environmental factors. However, a group of scientists from the Mount Sinai School of Medicine sought to explore the role of epigenetics with depression.
Epigenetics – a widely studied field- involves changes in how a gene is expressed that is not based on the DNA sequence but can be passed on through subsequent generations.
For instance, a single cell upon fertilization can change into many different types of cells as it grows into an embryo, but the DNA sequence itself is not altered.
Although many studies have focused on mothers and their offspring, very little research has examined the role of fathers from this perspective.
Mount Sinai scientists explored this by exposing male mice to a highly stressful environment; encounters with aggressive male mice, for example. These “defeated” mice along with the control – or “nondefeated” mice – then bred to produce offspring with normal females.
Through a battery of behavioral tests, and blood tests that monitored depression and anxiety, the authors found that offspring of the “defeated” mice showed a significant increase in both these measures compared to the “nondefeated” mice.
Although found in both male and female offspring, the male children seemed to experience more depression and anxiety than females.
These findings were also only found when mice were naturally birthed – not for offspring created through in vitro fertilization – suggesting that any changes in the children may not be due to epigenetics after all, but through behavior.
One possible explanation, as expressed by the authors, could be that female mice respond to the stress of the “defeated” male mice that result in her own biochemical changes; this in turn could affect the behavior her children.
In any event, the role of epigenetics and inheritance as it relates to depression, as well as anxiety, is highly complex, but something worth exploring further, according to lead scientist, Dr. Eric Nestler.
“This type of translational animal work is important to help scientists focus their work in humans”, says Dr. Nestler. “These findings in mice raise the possibility that part of an individual’s risk for clinical depression or other stress-related disorders may be determined by his or her father’s life exposure to stress, a provocative suggestion that now requires direct study in humans.”
“Paternal Transmission of Stress-Induced Pathologies” by David M. Dietz, Quincey LaPlant, Emily L. Watts, Georgia E. Hodes, Scott J. Russo, Jian Feng, Ronald S. Oosting, Vincent Vialou, and Eric J. Nestler. Oosting is affiliated with Utrecht University, Utrecht, the Netherlands. Biological Psychiatry, Volume 70, Number 5 (September, 2011),doi: 10.1016/j.biopsych.2011.05.005, published by Elsevier.
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