Long-term stress damages the brain

So stressed out you can’t think straight? Well, it turns out that’s not just a figure of speech. Long-term stress damages the brain, impairing everything from emotion and impulse control to certain big-picture analytical thinking.

“In essence, with chronic stress, you become more primitive,” says Amy Arnsten, professor of neurobiology at Yale University.

But before you stress out about that, consider Ms. Arnsten’s recent findings, published in the Sept. 7-11 issue of the Proceedings of the National Academy of Sciences. Her new research highlights ways in which this type of chronic-stress-induced brain damage can be not only stopped but reversed.

Turns out that when we have chronic stress, the brain gets flooded with an enzyme that effectively breaks down part of the structure (the dendritic spines) of the neurons in the prefrontal cortex, Ms. Arnsten explains.

So if we got rid of the enzyme (aka protein kinase C) - either by medication or natural stress reduction - the neurons would recuperate, right?

Indeed.

At least in otherwise healthy individuals, says B.J. Casey, director of the Sackler Institute for Developmental Psychobiology at Cornell University’s Weill Medical College.

Ms. Casey and a student, Conor Liston, tested the hypothesis on 20 medical school students. Scanning their brains during and after the students took their medical board exams (a very-high-stress period), the Cornell team saw that the damage to the prefrontal cortex done during the exams was completely mended a month later.

“A little bit of stress is good,” Ms. Casey says. “You can better focus on the task at hand.”

But that focus - and stress - comes at a cost, she explains, because while it enables us to better “hone in,” it also makes it much harder to shift our attention or even to notice our surroundings. We miss the bigger picture - the forest for the trees.

“It is a sort of conceptual blindness to our surroundings,” Ms. Casey says.

But remember, these medical students had no underlying health conditions. They recovered within a month - and what’s a little loss of temporary peripheral cognition if it means passing the boards, right?

It’s worse for people who have underlying conditions such as bipolar disorder, post-traumatic stress disorder or chronic depression and anxiety. In this population - where protein kinase C activity rarely wanes - the brain doesn’t get a break to recover.

There also are indications that children with high-lead-level exposure and those diagnosed with attention deficit hyperactivity disorder have increased protein kinase C activity, Ms. Arnsten says.

Certain existing medications, such as Lithium (a mood stabilizer used to treat bipolar disorder) have been shown to decrease the damaging enzyme production. In other words, for people with bipolar disorder, staying on their medications is crucial for maintaining normal levels of protein kinase C.

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