Why Stress Makes It Harder to Control Emotions

The findings suggest that certain therapies that teach people how to better regulate their emotions - such as those used to treat social anxiety and other psychiatric conditions - may not work well during stressful situations, the researchers said.

The study is published this week in the journal Proceedings of the National Academy of Sciences.

"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 study researcher Elizabeth Phelps, a neuroscience professor at New York University. "In other words, what you learn in the clinic may not be as relevant in the real world when you're stressed."

People commonly use their thoughts to change their emotions - for instance, when they think about a glass being half full instead of half empty, Phelps said.

Such techniques, called cognitive emotion regulation, can be taught to people in therapy. For instance, a person who develops anxiety in social situations might be asked to change the way they think about parties so that they see them in a different light and have a different emotional response to them, Phelps said.

In the new study, 78 participants viewed pictures of snakes and spiders. Some pictures were paired with an electric shock, and participants eventually developed a fear of these pictures. (They reported more intense feelings of fear when viewing the pictures, and a skin conductance tested showed they were more physiological aroused, compared with when they viewed images not paired with a shock.)

Next, the participants were taught therapeutic strategies, like those used in clinics, to reduce the fear induced by these pictures.

The next day, participants were randomly assigned to either place their hands in icy water for three minutes - a technique used in experiments to induce mild stress - or to place their hands in warm water.

Those who placed their hands in warm water showed a reduced fear response when they viewed the pictures of snakes and spiders, indicating that the participants were able to use the techniques they'd learned the previous day to control their emotions.

However, those who placed their hands in icy water showed no reduction in fear compared to the previous day.

Researchers know that it takes effort to think about situations differently, and that learning to regulate emotions relies on a brain area called the prefrontal cortex, Phelps said. However, the prefrontal cortex is highly sensitive to stress, Phelps said. This may explain why such cognitive-regulation strategies may not work when the person is under stress.

However, there may be a way to overcome this problem. When cognitive-regulation strategies are practiced so much that they become second nature, they require less usage of the prefrontal cortex, Phelps said.

In other words, the more these strategies are practiced, the easier it will be used them when you're stressed, Phelps said.