When life gets unpredictable, highly anxious people can have more trouble reading the environmental cues that could help them avoid a bad outcome. They may even catastrophize, for example, interpreting a lovers’ tiff as a doomed relationship or a pain in the arm as a heart attack symptom.
About 40 million American adults are affected by anxiety disorders.
A new study from scientists at the University of California, Berkeley, and the University of Oxford hints at an anomaly in the brain’s higher-order decision-making circuitry that could someday be targeted in new treatments for anxiety disorders.
“Our results show that anxiety may be linked to difficulty in using information about whether the situations we face daily, including relationship dynamics, are stable or not, and deciding how to react. It’s a bit like being Alice in Wonderland, trying to work out if the same rules apply or if everything is different and if so, what choices you should make,”
said senior author Sonia Bishop, an assistant professor of psychology at University of California, Berkeley, and principal investigator of the study.
Case in point: a friend may unexpectedly lash out for no apparent reason. That friend’s behaviour could be just a characteristic variation in their day-to-day mood or interactions or, more dramatically, an underlying change in their relationship with you.
The challenge for a person with anxiety is gauging the situation in the context of what else has happened recently and responding appropriately.
Probabilistic Decision Making
Bishop and fellow researchers used behavioral and physiological measurements, decision-making tasks, and computational models to assess the probabilistic decision-making skills of 31 young and middle-aged adults whose baseline anxiety levels ranged from low to extreme.
Probabilistic decision-making calls for logic and probability to process uncertain situations, drawing conclusions from past events to determine the best choice.
“An important skill in everyday decision-making is the ability to judge whether an unexpected bad outcome is a chance event or something likely to reoccur if the action that led to the outcome is repeated,”
The researchers’ measures also involved eye-tracking to detect pupil dilation. Pupil dilation is an indicator that the brain has released norepinephrine, which helps send signals to multiple brain regions to increase alertness and readiness to act.
Adjusting to New Choices
In the study, participants were asked to play a computerized slot-machine type game in which they continually chose between two shapes, one of which, if selected, would deliver a mild to moderate electrical shock.
To not get shocked, they needed to keep track of the shape that most often resulted in electrical jolts. And during one part of the game, the shock-delivering shape did not change for a long stretch of time.
Conversely, in another part of the game, it changed more frequently. Very anxious people had more trouble than their less anxious counterparts adjusting to this and thus avoiding shocks.
“Their choices indicated they were worse at figuring out whether they were in a stable or erratic environment and using this to make the best choices possible,”
Also more fragile in highly anxious participants was their pupil response to receiving a shock, or not, during the erratic phase of the game.
Usually, our pupils dilate when we take in new information, and this dilation increases in volatile environments. Smaller pupils hinted at a failure to process the rapidly changing information that was more prevalent during the erratic phase of the game.
“Our findings help explain why anxious individuals may find decision-making under uncertainty hard as they struggle to pick up on clues as to whether they are in a stable or changing situation,”
Anxious individuals have difficulty learning the causal statistics of aversive environments. Michael Browning, Timothy E Behrens, Gerhard Jocham, Jill X O’Reilly, Sonia J Bishop. Nature Neuroscience (2015) doi:10.1038/nn.3961
Hartley, C.A. & Phelps, E.A. Anxiety and decision-making. Biol. Psychiatry 72, 113–118(2012).