When things get unpredictable, people prone to high anxiety may have a harder time reading the environmental cues that could help them avoid a bad outcome.
A new study hints at a glitch in the brain’s higher-order decision-making circuitry that could eventually be a target in the treatment of anxiety disorders, which affect some 40 million American adults.
“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,” says senior author Sonia Bishop, an assistant professor of psychology at University of California, Berkeley, and principal investigator of the study.
“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,” she adds.
For example, a friend may suddenly lash out for no discernible reason. That friend’s behavior could reflect a typical 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 prone to anxiety is assessing the situation in context of what else has happened recently and responding appropriately.
Low to extreme anxiety
Bishop and fellow researchers used decision-making tasks, behavioral and physiological measurements, and computational models to gauge the probabilistic decision-making skills of 31 young and middle-aged adults whose baseline anxiety levels ranged from low to extreme.
Probabilistic decision-making requires using logic and probability to handle 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,” Bishop says.
The researchers’ measures also included eye-tracking to detect pupil dilation, an indicator that the brain has released norepinephrine, which helps send signals to multiple brain regions to increase alertness and readiness to act.
Are things stable or changing?
Participants were asked to play a computerized “two-armed bandit-style” game in which they repeatedly chose between two shapes, one of which, if selected, would deliver a mild to moderate electrical shock.
To avoid getting shocked, participants needed to keep track of the shape that most frequently delivered electrical jolts. During one part of the game, the shock-delivering shape did not change for a long stretch of time. However, during another part of the game, it changed more frequently. Highly 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,” Bishop says.
Also weaker in highly anxious participants was their pupil response to receiving a shock (or not) during the erratic phase of the game. Typically, our pupils dilate when we take in new information, and this dilation increases in volatile environments. Smaller pupils suggested 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,” Bishop says.
The findings appear in Nature Neuroscience.
In addition to Bishop, coauthors and researchers of the study contributed from the University of Oxford in England. The European Research Council and the US National Institutes of Health supported the work.
Source: UC Berkeley