Where do fears come from?

Where do fears come from?

Abstract: Exposure therapy for fears and phobias may only have a 50% success rate because fear memories last longer than competing safety memories learned through therapy. Researchers are investigating the genesis of fear memories and have developed a new mathematical model to help strengthen exposure therapies.

Source: University of Colorado

Exposure therapy is a major treatment option used by clinicians to help patients face and overcome their distressing and damaging fears. However, in as many as 50% of patients, fears may return.

Researchers at the University of Colorado recently published a study that presents revolutionary models of behavioral health. The study, published in Computational psychiatryshowed that fears are likely to persist because fear memories last longer than competing safety memories acquired in exposure therapy.

In the following Q&A, Joel Stoddard, MD, associate professor in the Department of Psychiatry at the University of Colorado School of Medicine, explains where our fears come from and how new research and mathematical modeling will help strengthen exposure therapy, based on the individual patient’s experience.

He also explains how the research was made possible by a strong collaboration across two University of Colorado campuses with Dr. Sarah Kennedy and Dr. Sam Paskewitz at CU Anschutz and Dr. Matt Jones at CU Boulder.

As a clinician and researcher, how do you define fear?

Fear is the response of a person’s whole body to a threat.

You are walking in the forest and you see a snake. Your body responds: “This is dangerous!” Your entire mind and body response to a snake is usually one of fear. So you will have the reaction you labeled as fear, a mixed state of feelings, thoughts, behaviors and physiological changes. Everyone experiences fear in a slightly different way depending on how they integrate the response components.

It is your entire response to the threatening situation, not just how you feel about it. Classically, your body prepares to deal with a threat with a “freeze, flight or fight” response.

Freeze: “Don’t notice me, please.” Flight: “I’ll run away while I still can.” And the struggle, our last refuge.

A snake on a field trip seems to be an innate reaction. What about learned or conditioned fears?

So that’s the next step. When we talk about fear, we are basically talking about a type of response to a threat. Things that threaten you are things that will harm you.

There are a bunch of things in the world that can trigger a fear reaction that we don’t know exactly why. Some people are afraid of snakes even though they have never been hurt. This is called unconditional fear.

Conditioned fears differ in that they are learned. For example, a car accident is a huge life-threatening event. Many times people will learn to fear certain things that were not scary before the car accident. As well as the steering wheel. Steering wheels usually do not injure people.

But our car accident victim was focused on the wheel at the time of the accident. And so now whenever they see a steering wheel, they have a significant life-or-death reaction. Steering wheels are now part of the new threat memory. The reaction to the steering wheel is a conditioned fear reaction.

So, considering conditioned fears, what are the different types of fear that you see in your work?

First, let’s be clear and distinguish between the different threat response disorders:

  • Post-traumatic stress disorder (PTSD). When you have an event, you have an upsetting and damaging reaction to the trauma experience including fear of the things you learned to fear during that traumatic event. This can be like the car accident example I mentioned or the post-traumatic fear responses experienced by soldiers in conflict zones.
  • Anxiety disorders. Anxiety disorders are a fear response to a threat that you have not yet encountered or to an expected threat. “I didn’t do well on that test,” for example.
  • Panic disorders. It’s like having a strong fear reaction out of the blue. To many, this may seem like a heart attack.

In general, they represent examples of different types of disorders in which people have problems with their responses to fear. Panic: fear reaction without threat. Anxiety: a fear reaction to an anticipated threat. Posttraumatic stress: response to threat memory.

What is exposure therapy and is it historically the best treatment option for fear?

Exposure therapy is a highly effective evidence-based intervention that emerged from psychiatry in the mid-20th century.

Let’s say you’re afraid of heights. There is this ladder and you have to climb it to fix something. But you are paralyzed by your fear. You just can’t climb that ladder. It’s too scary for you to do that.

In general, therapy is putting yourself in a situation to do what you fear while in a safe environment. You learn that you are safe, and then you transfer that learned memory to safety. Safety memory competes with threat in height.

Our work has much broader implications for exposure therapy alone. Exposure is actually a technique that is the active ingredient in many therapies that target threat.

In PTSD, for example, indicated therapies may include trauma-focused cognitive behavioral therapy, narrative therapy, or eye movement desensitization and reprocessing. These are all very different types of therapies that, looking under the hood, reveal that they have some sort of exposure element to target the threat.

They bring the individual closer to their feared threat memory, but they also empower the individual and provide safety memories that compete with threat memories in various ways.

Why did you and your team decide to investigate improving exposure therapy?

It was a really serendipitous moment where chocolate met peanut butter. I was recruited to CU Anschutz to learn different mathematical models of the mind and how we can apply them to healing.

Exposure therapy is generally super effective, but for 50% of people, it’s not that effective, and for many, it’s not long-lasting. This is because their fears may return over time. Without a permanent backup memory, the patient’s memories are persistent and lead to repeated fear reactions.

The fear response can return if the person is threatened again or perhaps found to be triggered in a different context. Sometimes their symptoms are milder. Unfortunately, full symptoms can return.

My colleagues and I were in Matt Jones’ office talking. Matt is a prolific genius for rigorously mapping psychological processes into mathematics. He and Sam Paskewitz worked on how stimuli compete to trigger memories. I have previously studied the brain basis of threat/safety memory competition in humans. The light bulbs were going out.

So when I heard about their new experiment, I immediately asked them to apply it to threat learning. We later asked Sarah Kennedy for help because she has a good understanding of how fear learning theory can be applied to therapy and is a leading expert on experimental behavioral therapies on campus. It was all here at CU.

We had to come up with a mathematical framework that explains all that – what is observed in humans and experiments. All without exception. Once you express it mathematically, it means that you now have a precise theory. This is a hot topic and people have been trying to figure out how we can map it for a while, mostly because the basic science is so good.

Fortunately, we have connections between CU Boulder and CU Anschutz and AB Nexus, both in the modeling and clinical health aspects. So, in order to avoid the punches and honor the work of my colleagues, they honestly integrated an extensive body of work into a coherent theory of the treatment of fear, expressed in mathematics.

What can you conclude from your math and equations? How does it show the new model and paradigm for exposure therapy to be more long-lasting?

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The big takeaway was the potential for precision medicine in behavioral health, to borrow a popular phrase.

What if instead of months of exposure therapy, we could tell you within a week or two if it’s the right therapy? What if you are in exposure therapy, very invested, but have trouble learning threats? We can tell you that early.

This shows a scared woman
Fears are likely to persist because fear memories last longer than competing safety memories acquired in exposure therapy. The image is in the public domain

Mathematically, this research is analogous to Newton’s equations in physics. These are simple, elegant equations that help describe motion and force. They are not perfect, but they strongly predict everyday rough movements. With them you can land a person on the moon. More complex elaborations, such as relativity and quantum physics, exist for narrow problems. We actually tested stress resistance and developed models for therapy, but found that they needed a little more work.

We were successful because we built on enormous experimental and mathematical work—translating and in some places revising the family of Rescorla-Wagner equations. This is specifically for use in measuring and predicting learning processes involving threat memories.

By detailing a set of equations to measure and predict how people acquire and forget both safety and threat memories, we may be able to better help individuals who have problems with their fear responses to threats. It affects an incredible percentage of people during their lifetime and is the leading cause of disability worldwide, including all diseases.

We already have preliminary evidence that we can use this family of equations to predict how well patients will respond to treatment based on how much they have learned during their treatments.

Let’s say you’re in your therapist’s office: you connect your therapist and that office with security. These safety signals actually help you prevent a threat response. And so, as soon as you leave your therapist’s office, if you don’t learn to generalize those safety memories, your fear response may return. Unfortunately, experiments and models show that safety memories are less stable than threats.

Since the equations summarize all of our theory in a compact form, it’s easy to see exactly how things are related. The future is exciting for behavioral health research. There are actually numerous implications for practice and predicting individual responses for those who bravely read the paper. It is the start of an exciting new theory-testing research program that integrates more than 50 years of work on threat learning for patient care.

About this fear and news about therapy research

Author: Press office
Source: University of Colorado
Contact: Press Office – University of Colorado
Picture: The image is in the public domain

Original research: Open access.
Explaining the return of fear with the revised Rescorla-Wagner models” by Samuel Paskewitz et al. Computational psychiatry


Explaining the return of fear with the revised Rescorla-Wagner models

Exposure therapy—exposure to a feared stimulus without adverse consequences—can reduce fear responses in many mental disorders.

However, such relief is often partial and temporary: the fear may return after the end of therapy. Conditioning research has identified three mechanisms for the return of fear, i.e., a change in the physical context (reinstatement), the passage of time (spontaneous recovery), and encountering an unconditioned fear-inducing stimulus (reinstatement).

In order to understand why fear returns and thereby develop more effective therapies, we are developing models of learning mathematics based on the models of Rescorla and Wagner. According to this model, context cues present during extinction become conditioned inhibitors (i.e., safety signals) that prevent complete erasure of the threat association. Adding different mechanisms to the model allows explaining different aspects of fear recovery.

Among these mechanisms is the decay of inhibitory associations, which provides a new explanation for spontaneous recovery. For the benefits of exposure to be robust and lasting, the degree to which the extinction context becomes inhibitory needs to be minimized in order to maximize unlearning.

We simulate several experimental paradigms that reduce the return of fear and explain them according to this principle.


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