Stress May Be Linked to Previous Generation's Chemical Exposure

The reason you stress out might have nothing to do with you or the environment around you. In fact, you might want to blame your grandparents. Keep in mind, however, that they had nothing to do with it. At least they didn't do it knowingly.

A new study has shown that exposure to certain chemicals can raise a descendant's sensitivity to stress.

Researchers at both The University of Texas at Austin and Washington State University have observed that when rats are exposed to vinclozolin, a widely-used fruit and vegetable fungicide, their offspring tended to exhibit greater anxiety and increased activity in the stress-related parts of their brains.

"The ancestral exposure of your great grandmother alters your brain development to then respond to stress differently," said Michael Skinner from Washington State University. "We did not know a stress response could be programmed by your ancestors' environmental exposures."

Vinclozolin's effect on subsequent generations has already been studied in rats. What was observed then is a process called epigenetics. Epigenetics occurs when heritable changes concerning gene expression or cellular phenotype are due to factors other than DNA. In that study, the rats began altering the way they chose mates.

In this study, after being exposed to vinclozolin, behavioral tests were run on the third generation of the rats.

David Crews, the other researcher from The University of Texas at Austin explained, "We are now in the third human generation since the start of the chemical revolution, since humans have been exposed to these kinds of toxins. This is the animal model of that."

When a person feels stressed, cortisol is secreted from the adrenal gland. Cortisol-induced stress is also a condition where the person feels stressed because the cortisol is being secreted. This study was one of the first to physiologically look at trans-generational, chemically-induced traits.

The results were a huge eye-opener for Crews.

"There is no doubt that we have been seeing real increases in mental disorders like autism and bipolar disorder. It's more than just a change in diagnostics. The question is why? Is it because we are living in a more frantic world, or because we are living in a more frantic world and are responding to that in a different way because we have been exposed? I favor the latter."