A new study finds that even mild stress can affect your ability to control your emotions.
A team of neuroscientists at New York University say that their findings suggest that certain therapies that teach people how to better regulate their emotions - such as those used to treat social anxiety and phobias - may not work as well during stressful situations.
"We have long suspected that stress can impair our ability to control our emotions, but this is the first study to document how even mild stress can undercut therapies designed to keep our emotions in check," said senior author and psychology professor Elizabeth Phelps. "In other words, what you learn in the clinic may not be as relevant in the real world when you're stressed."
To help patients learn to control their emotional maladies, therapists sometimes use cognitive restructuring techniques encouraging patients to alter their thoughts or approach to a situation to change their emotional response. These might include focusing on the positive or non-threatening aspects of an event or stimulus that might normally produce fear.
To test how these techniques hold up in real-life situations, the team enlisted a group of 78 volunteers, who viewed pictures of snakes and spiders. Some of the pictures were paired with an electric shock, and participants eventually developed a fear of these pictures. LiveScience reports that the subjects "reported more intense feelings of fear when viewing the pictures, and a skin conductance tested showed they were more physiologically aroused, compared with when they viewed images not paired with a shock."
Next the participants were taught cognitive strategies, similar to those prescribed by therapists and known as cognitive-behavioral therapy (CBT), to learn to diminish the fears brought on by the experiment.
The next day, the participants were put into two groups: "the stress group" and "the control group." In the stress group, participants' hands were submerged in icy water for three minutes - a standard method for creating a mild stress response in psychological studies. In the control group, subjects' hands were submerged in mildly warm water. To determine that the participants in the stress group were, in fact, stressed, the researchers gauged each participant's levels of salivary cortisol, which the human body is known to produce in response to stress. Those in the stress group showed a significant increase in cortisol following the stress manipulation, whereas there was no change in the control group.
After a short delay, the researchers then tested the participants' fear response to the same pictures of snakes or spiders in order to determine if stress undermined the utilization of the cognitive techniques taught the previous day.
As expected, the control group showed diminished fear response to the images, suggesting they were able to employ the cognitive training from the previous day. However, even though the stress group received identical training, they showed no reduction in fear, indicating they were unable to use these cognitive techniques to reduce fear on the second day.
"The use of cognitive techniques to control fear has previously been shown to rely on regions of the prefrontal cortex that are known to be functionally impaired by mild stress," Phelps said.
"These findings are consistent with the suggestion that the effect of mild stress on the prefrontal cortex may result in a diminished ability to use previously learned techniques to control fear."
The study, announced Monday, is published in the journal Proceedings of the National Academy of Sciences.