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Study: Fear of the Unknown Compounds Many Anxiety Disorders

Ambiguous or uncertain threats drive most fear-based psychopathologies.

Dean Drobot/Shutterstock
Source: Dean Drobot/Shutterstock

Having an increased sensitivity to ambiguous, uncertain threats—or a hypervigilant fear of the unknown—is at the root of most fear-based psychopathologies according to a new study from the University of Illinois at Chicago (UIC). The November 2016 findings were published this week in the Journal of Abnormal Psychology.

The researchers found that a wide range of anxiety disorders—including panic disorder, social anxiety disorder, and specific phobias—all share a common response to generalized feelings of apprehension and heightened reactivity triggered by the unpredictability of ambiguous threats. In the impact statement for this study, the researchers said:

“This study suggests that individuals with current, fear-based internalizing disorders display exaggerated anticipatory anxiety in response to uncertain or ambiguous threat.

"The findings also suggest that this is not the case for individuals with distress/misery disorders as they were found to display relatively normal responses to uncertain threat. Responding to uncertain threat may be a key neurobiological factor that distinguishes fear-based from distress/misery disorders.”

For example, when someone is hypersensitive to the risk of experiencing an uncertain threat, he or she can spend the entire day in a state of free-floating anxiety catastrophizing about something bad that could happen to him or her based on an unknown entity.

These findings are especially poignant at a time when there is so much fear-based rhetoric fueling a collective state of uncertainty and fear of the unknown. The good news is that the outcome of this research could lead to more effective treatments that target the common root of fear-based psychopathology.

In a statement to University of Illinois Chicago, Stephanie Gorka, research assistant professor of psychiatry and a clinical psychologist in the UIC College of Medicine and corresponding author on this study on the common roots of fear-based psychopathology said:

"It's what we call anticipatory anxiety. It could be something like not knowing exactly when your doctor will call with test results ... We may, one day, open up clinics that focus on treating the underlying common neurobiology of the patient's symptoms instead of individual diagnoses. A treatment, or set of treatments, focused on sensitivity to an uncertain threat could result in a more impactful and efficient way of treating a variety of anxiety disorders and symptoms.”

Panic disorders are a perfect example of anticipatory anxiety. When someone is constantly anxious over the unpredictability of when and where he or she might have a panic attack; the fear of fear itself becomes the biggest problem. The fear of having a panic attack in public can lead someone to become agoraphobic and never stray from ''safe spaces." This can create a downward spiral of social isolation, depression, and paralysis to perform instrumental activities of daily living (IADLs).

Anecdotally, a friend of mine broke the vicious cycle of her fear of panic attacks preventing her from going about day-to-day activities by always having a Xanax close at hand. Years would eventually go by without a panic attack (or ever having to take a benzodiazepine) simply because she knew...if some unexpected stimuli triggered a panic attack, she could simply reach into her pocket for a tranquilizer and nip the anxiety in the bud before it snowballed out of control. This gave her peace of mind and a sense of control, which reduced the power of the ambiguous threat of having a panic attack to interfere with her daily life.

On the flip side, predictable threats in the here-and-now typically produce a very tangible and instinctive fight-or-flight response that has a clear trigger—such as a barking dog chasing you down the street—that subsides once the antagonistic threat has disappeared or there is a resolution to the potential conflict.

Unfortunately, fear of the unknown and the uncertainty of ambiguous threats is often projected onto unfamiliar outside groups that may share different beliefs than your "ingroup." I tackled this topic in two previous Psychology Today blog posts: “Your Brain Can Learn to Empathize With Outside Groups” and “Why Are Some Neighborhoods Becoming Extremely Homogenized.”)

Unpredictability and Ambiguous Threats Can Evoke Visceral Fear-Based Responses

For the recent study on fear-based psychopathology, Gorka and colleagues measured study participants' eye-blink responses to a predictable and unpredictable mild electric shocks to his or her wrist.

Study participants ranged from 18 to 65 years of age. Forty-one control subjects had no current or prior diagnoses of psychopathology. Of the other participants: 25 suffered from major depressive disorder; 29 with generalized anxiety disorder; 41 with social anxiety disorder; and 24 with another specific phobia.

The researchers measured the strength of the eye blinks using a special electrode under each participant's eyes. The scientists compared the strength of the blinks in response to tones delivered during the predictable shock to eye blinks that occurred during the unpredictable shock.

Gorka et al. found that participants with social anxiety disorder or a specific phobia blinked much more strongly during the unpredictable shocks. Participants without a mental health diagnosis, major depressive disorder, or generalized anxiety disorder blinked less intensely during unpredictable shocks.

Interestingly, eye-blink responses are rooted in the cerebellum (Latin for "little brain") which is responsible for fine-tuned motor control and is the seat of muscle memory. Recent studies have also found strong ties between the cerebellum, autism spectrum disorders (ASD), post-traumatic stress disorder (PTSD), emotion regulation, and creative capacity.

To elicit eye blinking during the shock task, the participants heard short, acoustic tones via headphones. As Gorka explained, "No matter who you are or what your mental health status, you are going to blink in response to the tone. It's a natural reflex, so everyone does it, without exception."

Based on these findings, Dr. K. Luan Phan, professor of psychiatry and UIC director of the mood and anxiety disorders research program, and senior author on the study concluded:

"We classify so many different mood and anxiety disorders, and each has its own set of guidelines for treatment, but if we spend time treating their shared characteristics, we might make better progress.

"Knowing that sensitivity to uncertain threat underlies all of the fear-based anxiety disorders also suggests that drugs that help specifically target this sensitivity could be used or developed to treat these disorders."

What Role Does the Cerebellum Play in Fear-Evoked Freezing?

Life Science Databases/Wikimedia Common
Cerebellum in red.
Source: Life Science Databases/Wikimedia Common

Anytime I feel inclined to curl up in the fetal position and hide under the covers to avoid ambiguous threats, I force myself to lace up my sneakers and face the world via robust physical activity. For me, choosing to seize the day and “take flight” through aerobic exercise breaks the paralytic power of anticipatory anxiety by making me feel like I am the ruler of my destiny.

Throughout my lifespan, daily physicality has fortified my courage to "slay the dragon" of my own fear-based psychopathologies head-on. If you are prone to fear-based anxiety, maybe exercise can be something within the locus of your control that serves as an elixir to minimize your fear of the unknown, too?

How does regular physical activity break the cycle of fear-evoked paralysis? In 2014, neuroscientists at the University of Bristol discovered a unique brain pathway they believe is the root of the universal response of animals and humans to freeze in place when we’re afraid. Their revolutionary study unearthed a chain of neural connections stemming from the cerebellum.

More specifically, the researchers found the neural substrates that underlie fear-evoked freezing stem from a periaqueductal grey-cerebellar link. (Cerebellar is the sister word to cerebral and means "relating to or located in the cerebellum").

During their experiments, the Bristol researchers found that a real—or imagined—threatening stimuli, activated periaqueductal grey-cerebellar neural networks which caused the body to automatically freeze in place. They believe that a better understanding of how these central neural pathways rooted in the cerebellum function could bring us closer to developing effective treatments for emotional disorders such as panic attacks, phobias, and general anxiety.

Anecdotally, I know from life experience and coaching others that regular physical activity—including a combination of various intensities of aerobic exercise, strength training, and mindfulness-meditation/yoga—all engage the cerebellum in dynamic ways.

Based on my understanding of cerebral-cerebellar structural and functional connectivity, I have a hunch that physical exercise may be a valuable drug-free tool for combating fear-based psychopathology. This is just an educated guess. That being said, regular physical activity will undoubtedly fortify your resilience, chutzpah, and Sisu to face real and imaginary fears of the "boogieman" that manifest in various ambiguous forms and uncertain threats with boldness.

Stay tuned for more on this exciting topic and empirical evidence offering new science-based ways to break the cycle of fear-evoked paralysis and free-floating anxiety of the unknown.


Stephanie M. Gorka, Lynne Lieberman, Stewart A. Shankman, K. Luan Phan. Startle Potentiation to Uncertain Threat as a Psychophysiological Indicator of Fear-Based Psychopathology: An Examination Across Multiple Internalizing Disorders. Journal of Abnormal Psychology, 2016

Koutsikou S, Crook JJ, Earl EV, et al. Neural Substrates Underlying Fear-Evoked Freezing: The Periaqueductal Grey–Cerebellar Link. The Journal of Physiology, 2014

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