Exposure is About Learning, Not Habituation

When I was first trained in exposure therapy, I was taught that exposure works because the patient habituates (gets used) to the stimulus that causes them anxiety, or habituates to the feeling of anxiety itself.  On paper, this makes a lot of sense. Here’s how I used to explain it to patients:

“If a person is scared of dogs, and they cross the street every time they see a dog and avoid any place where they might run into a dog, that person will never get used to dogs, and so their fear will never go away.  But if that person chooses to be around dogs despite their fear, they will eventually get used to being around dogs and no longer be afraid. In other words, they will habituate to dogs.”

I would then apply this concept to whatever it was that the patient was afraid of: “If you avoid talking to new people, you’ll never habituate to it”; “If you avoid things that trigger uncertainty about getting sick, you’ll never habituate to that uncertainty.”

This all sounded very logical.

But the more patients I saw, the more I was convinced that habituation wasn’t actually what made people get better, and that thinking about exposure through this lens could sometimes backfire.  I started thinking that exposure actually worked by:

  • Showing patients that even when they are scared, they can make the choice not to do a compulsion and not to avoid
  • Showing patients what happens when they let go of avoidance and compulsions. 

The former type of learning is self-explanatory.  People with OCD typically don’t feel that they have a choice about whether to engage in compulsions and avoidance, when in reality they do have a choice and they’re just scared to stop. ERP shows the person that they can choose to refrain from compulsions and confront things they are avoiding, even when they’re scared.

The latter type of learning is more multifaceted, but broadly speaking it includes two types of learning:

  • Learning how you feel when you stop engaging in avoidance and compulsion.  For example, seeing that you feel less guilty when you stop ruminating about potential sources of guilt; seeing that you feel less contaminated when you stop trying to prevent contamination; seeing that if you don’t tap it twice, the ‘off’ feeling fades away on its own; seeing that when you stop protecting yourself from a threat, you stop feeling threatened by it.
  • Learning what happens, on a concrete level, when you don’t engage in avoidance and compulsion.  For example, eating sushi and seeing that you don’t throw up; expressing anger and seeing that others don’t reject you; not checking the stove and seeing that the house doesn’t burn down.

Around the same time as I was beginning to think this way, I learned about some new research on ‘inhibitory learning’ that was pointing in the same general direction.*  This research suggested that exposure works because it provides opportunities for learning experiences that disconfirm a person’s negative expectations (e.g., Jacoby and Abramowitz, 2016).**

During this same period, I also had the privilege to complete advanced training with Dr. Elna Yadin, one of the world’s experts on exposure therapy for OCD and PTSD.  Dr. Yadin put it best: “Earthworms habituate. People learn.” According to her, the idea that exposure therapy is based on learning is not a new idea at all.

But does it really matter why exposure works?  Isn’t the distinction between habituation and learning just academic and theoretical?  No, in fact there are many practical implications to this distinction. Here are some implications of looking at exposure from the perspective of learning, as opposed to desensitization:

  1. The goal of an exposure is not to make you anxious, and it’s okay if it doesn’t.  If you are giving yourself the opportunity to learn something new by doing something you’ve previously avoided, or by doing something without an accompanying compulsion, that’s a good exposure.
  1. An exposure that makes you anxious but doesn’t involve any new learning is a waste of time.  A huge amount of time and energy (and money) is wasted on exposures like this.
  1. Exposure without Response Prevention is completely useless, because the types of learning discussed above are precluded by compulsions.  (In contrast, if habituation were what mattered, exposure might work despite the presence of some compulsions, as long as the person were still anxious.)
  1. There is no reason to “stay with the anxiety,” and in fact it’s better not to.  I want my patients to learn that they can move on after something triggers anxiety.  In my experience, when people “stay with the anxiety” they often end up ruminating and making themselves more anxious, with no added benefit.
  1. There is nothing wrong with using ‘coping skills’ to calm yourself down when you’re anxious, as long as the coping skill isn’t functioning as a compulsion.  Some people who think that exposure works because you habituate to the anxiety discourage patients from doing anything to lessen their anxiety. I strongly disagree with this.  In fact, I encourage the use of ‘coping skills’ as a way to get through an episode of acute anxiety without resorting to a compulsion. The exception to this would be a case where the person is afraid of the anxiety itself (e.g., “If I get too anxious I’ll lose control, never stop feeling anxious, etc.”).
  1. ‘Imaginal exposure’ is only helpful if it provides an opportunity for learning.  (For an in-depth discussion, check out Using ‘Imaginal Exposure’ When Practicing ERP from a Learning Perspective.)

To illustrate the above distinctions, consider the example of an exposure for emetophobia (fear of vomiting):

Here is what an exposure for emetophobia might look like when the goal is learning:

Eat an avoided food and then move on with your day.  Don’t ruminate about it or monitor your body for signs of nausea.  Give yourself the chance to learn that you can do something despite your fear.  Give yourself the opportunity to learn that you don’t actually vomit and that if you stop ruminating and checking, the fear resolves pretty quickly on its own.  If you have trouble moving on, by all means do something to calm yourself down or get distracted, as long as whatever you’re doing isn’t aimed at preventing vomiting.

Here is what an exposure for emetophobia might look like when the goal is habituation:

Eat an avoided food and then sit there and imagine yourself vomiting over and over.  Habituate to the possibility of vomiting.

As you can see, there are significant practical differences between these two approaches.  In my experience, approaching exposure therapy from the perspective of learning makes the treatment faster, more effective, and much less unpleasant for the patient.

 

Notes and references:

*While I believe this is one aspect of why exposure works, I believe the other types of learning mentioned above (i.e., seeing that you have a choice; seeing that you feel better) are actually more important (because most of the time people with OCD already know that what they’re afraid of isn’t likely to happen).  Nonetheless, I’m happy that research is beginning to think about ERP in terms of learning.


**Jacoby, R. J., & Abramowitz, J. S. (2016). Inhibitory learning approaches to exposure therapy: A critical review and translation to obsessive-compulsive disorder. Clinical Psychology Review, 49, 28-40.