People living with anxiety-related disorders (anxiety disorders, OCD, PTSD) often report holding back from trying new things, saying no to social events, or not pursuing job opportunities - patterns of avoidance that, in the long run, keep them from living the life they want. These patterns of avoidance contribute substantially to distress and impairment, and breaking out of avoidance patterns is a central goal of treatment for anxiety-related disorders, which can include cognitive-behavioral therapies and medications.
However, even with the best treatments, some patients stay stuck in avoidance patterns. As clinician-neuroscientists, our research team at the University of Minnesota - Twin Cities wanted to better understand the brain patterns underlying avoidance, to guide the development of improved treatments. Our research was inspired by the observation that "avoidance" does not appear to be a unitary construct that affects every patient in the same way. When we talked to patients with anxiety-related disorders, they described all kinds of things that lead them to avoid: fear, apathy, self-doubt, habit, and more. This led us to the question: what happens in the brain to give rise to avoidance, and how is this different in people with anxiety-related disorders?
To investigate this, we used functional magnetic resonance imaging (fMRI) to assess brain activity in adults with and without anxiety-related disorders while they completed a computer task (shown below) involving avoidance decisions. In the task, participants' goal was to travel from the shed to the garden to harvest crops. They could choose to take a risky "short path" which guaranteed a win, but came with the risk of mild electric shock. Or, if participants chose instead to take the "long path" they were absolutely safe from shock, but might not reach the crops in time for harvest. Participants had to watch the shapes in the middle of the screen to learn when they were actually at risk for shock. Thus, participants had to learn how to maximize their long-term rewards (i.e., harvest) while also staying safe. We applied univariate and multivariate analyses to understand the patterns of behavior and brain activity that drive avoidance.
Rather than a strict categorical difference between those with and without anxiety-related disorders, we found two neurobehavioral dimensions relating to avoidance across the sample. People with more anxiety sensitivity, or "fear of fear," showed more avoidance when neural fear-excitation regions were active. By contrast, people with more intolerance of uncertainty, or "fear of the unknown," had avoidance that was harder to predict from brain activity in multivariate pattern analysis (shown below).
What does this tell us about anxiety-related disorders? One conclusion that stands out is that people with anxiety-related disorders don't have categorically "different brains." Anxiety and avoidance varied dimensionally across the sample. A second key takeaway is that avoidance isn't one thing. In the brain, "fear of fear" and "fear of the unknown" drive avoidance in distinct ways, indicating a need for distinct kinds of treatment. In other words, a dimensional approach to looking at avoidance across anxiety-related disorders appears to be more useful than thinking strictly in categories.
In future research, we hope to extend these findings to find new ways of treating avoidance, so that future treatments can be even more effective at helping people with anxiety-related disorders face their fears.