Feeling stressed at work? Well, at least there’s a silver lining — stress may help us fight of anxiety disorders, according to new research.


Image credits Gerd Altmann.

Stress can have an important part to play in extinction learning, which is the dismantling of previously-learned associations, according to a new study from the Ruhr-Universität Bochum’s Institute of Cognitive Neuroscience. The findings could help us develop new and improved ways of treating anxiety disorders.

Rings a bell

If an animal is repeatedly presented with two paired stimuli, its brain will start to associate the two at some point. In time, if this link is reinforced, the animal will start exhibiting responses to both stimuli even if only the first one is presented. These are known as conditioned responses and were first documented in Pavlov’s famous bell-and-treat experiments.

One darker and less known side of conditioned responses is that they may underpin anxiety disorders. Luckily, however, they can also be used to treat such disorders. For example, if a patient is progressively exposed to objects that trigger an anxiety attack, he or she can learn, in time, to decouple that trigger from feelings of anxiety. This process of progressive decoupling of the stimuli from their anxiety (or any other second stimulus) is known as ‘extinction learning’.

“It is generally assumed that extinction plays a vital role in exposure therapy,” says Dr Christian Merz, co-author of the paper.

It’s not yet exactly clear if this process is more similar to the brain ‘forgetting’ the old link, or to it ‘learning’ a new link that takes its place. What is clear, however, is that this process is highly dependent on context, says first author Shira Meir Drexler.

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“If a person learns in their therapist’s practice that a spider is no cause for fear, they might still react with fear to arachnids in their own basement.,” she explains.

Fear the lamp!

The team is the first to show that stress can break this context dependence — in essence, making it possible for someone to unlearn negative associations for good.

They worked with 40 participants over a three-day trial period. On the first day, participants were asked to view a computer screen, and the team showed them pictures of a desk lamp in an office setting. Every time this lamp was shown lit up in a particular color, viewers received mild electrical stimulation of the skin. The current wasn’t powerful enough to cause pain, but it was unpleasant to the participants. All other colors weren’t accompanied by the electric stimulation — thus making the participants associate light of a certain color to the unpleasant sensation.

Skin conductance response tests were used to confirm that the participants had learned this conditioned response by the end of the first day.

On the second day, half of the group was placed in a stressful situation before the trials. They had to hold one hand in ice water while being filmed and monitored by a supervisor for good measure. The other half of the group was not subjected to the stress test. Afterward, all participants were shown a series of photographs depicting a lamp once again. This time, however, there was no electrical stimulation applied following any of the colored lights. The setting had also changed — this time, the lamp lounged in a library instead of the office.

On the third day, the team presented both the office and the library photos of the lamp emitting colored light without following it up with electric stimulations.

The team reports that throughout the second and third days of viewing, participants in the stress group showed less intense anxious responses to the colored light they were primed for during the first day (in the office setting), and no response to the library setting. The non-stress group continued to show the same anxious response to the specific light color in the office setting when presented to them on the third day. They didn’t show any anxiety in the library context, suggesting that extinction learning only took place for them in the library, not the office, setting.

“Pharmacological studies have demonstrated that the treatment of anxiety disorders can be improved if the stress hormone cortisol is administered to the patients,” says corresponding author Oliver Wolf. “Our study has produced evidence for an underlying mechanism.”

Based on these findings, the team plans to investigate whether experiencing a stressful scenario prior to exposure therapy can help improve results.

The paper “Preextinction Stress Prevents Context-Related Renewal of Fear” has been published in the journal Behavior Therapy.