Research Review: Improving Exposure Therapy

This is my very first post, so I’m going to begin with one of my favorite topics-Inhibitory Learning. Here’s the reference if you want to check it out:

Craske, M. G., Treanor, M., Conway, C., Zbozinek, T., & Vervliet, B. (2014). Maximizing Exposure Therapy: An Inhibitory Learning Approach. Behavior Research Therapy, 58, 10-23. doi:10.1016/j.brat.2014.04.006.

Let’s just cut to the chase here. Exposure response prevention (ERP) therapy is the treatment for anxiety disorders. What is ERP? In very, very oversimplified terms it’s treatment where you face your fears and learn to overcome your anxiety. It’s a form of Cognitive Behavior Therapy. I’ll go into more depth in another article. But trust me, when done well it works!

This article starts by saying that exposure therapy is based on one of two different models or theories:

  1. Habituation – That sticking with it will result in a decrease in anxiety over time
  2. Disconfirmation of beliefs – That proving a belief wrong will result in a decrease anxiety over time

However, they identify a third model called the inhibitory learning model, and the point of the article is to explain why this can improve anxiety treatment.

Let’s imagine your fear is moths. They just freak you out! Who knows why this happened, but the point is you’re afraid of them. You’d rather walk over coals than be in a room with a moth. In both habituation and disconfirmation models of exposure, you basically face your fear and learn to not be afraid anymore. That is, you “extinguish” your fear. The neural connections just stop being present in your brain anymore. Moths don’t scare you anymore. Full stop. However, inhibitory learning says that following exposure treatment your fear, moths, has two meanings in your brain because there are now two neural pathways – the original “get me out this place” pathway/reaction, and the new “moths don’t scare me anymore”. [Note: I don’t know of any physiological findings that show without doubt the existence of two different neural pathways in the brain.]

So which one is right – how can we know? Well, the authors say there are some reasons why they are right – things that can only be true if there are two different neural pathways in the brain:

1. People’s fear can spontaneously show up again.

2. The fear can show up in different settings than treatment. If exposure was only done in an office, then the fear can show up again in other settings.

3. The fear can show up very quickly again if a person has a bad experience with that fear (e.g. a moth attacks them).

4. The fear can reappear if a person experiences stressful situations.

At this point you might be asking yourself why any of this is important. Hopefully it’s interesting. Well, the implications for exposure response prevention (ERP) treatment are actually a really big deal, and that’s the whole point of this article. Using this idea you can actually make ERP better, by strengthening the “moths are not scary” neural pathway. As an analogy, imagine you’re driving home and you have to get there as quickly as possible. You could take the side roads, but they are small and slow (i.e. the old, fear learning pathway), or you could take the highway that is fast with lots lanes (i.e. the newly learned pathway). Hopefully, you’d take the highway! This article basically says that through ERP treatment you build that highway as big as possible so that your brain always goes that new route, and moths are not scary anymore! The authors present some ideas for how to enhance exposure therapy based on inhibitory learning. I’ll try to summarize some of these ideas as best I can:

1. Expectancy Violation

When doing ERP, your job is to violate the fear as much as possible. One caveat here – treatment should be gradual (don’t start with the hardest exposure ever!). If you fear a moth will crawl into your ear, you need to find ways to really violate this expectancy (assuming moths rarely do this). So, being in a room with a moth isn’t enough. You have to expose your ear to it. Maybe try and call it over (that works, right?). Stand under a light while doing so. You get the picture. If the moth doesn’t crawl in your ear, or it does but it wasn’t terrible, then you have succeeded in your first trial. The key learning is i) did the negative outcome occur and ii) was the exposure tolerable. It is therefore critical that after exposure you review what was learned, and focus in on these expectancy violations.

  • One other important point here. They say you shouldn’t use cognitive or other strategies to decrease your anxiety during ERP. This decreases the expectancy violation effect and makes exposures less effective.

2. Deepened Extinction

Doing ERP with a moth in a therapist’s office is fine. However, once mastering some of these exposures, you want more fear triggers at the same time. For moths, imagine that nighttime triggers the fear, as does having your ears exposed. Based on this, you would want to do exposures combining all three – moths, at nighttime, with your ears exposed. These multiple triggers together are called deepened extinction.

3. Occasional Reintroduction of Fear

If your treatment is going well, that’s wonderful. However, we have to make it less likely that your fear will come back. That’s why you should try to reintroduce some of the fear from time to time. For moth fear, that might mean watching a video of a moth crawling on someone’s face, or doing something else that might be scary! This sounds horrible, but think of it like a mini psychological vaccination against your fear!

4. Remove Safety

Safety signals can be anything. They are things that make someone feel safe from their fear, which is good, but it stops them learning that they don’t need these things to be safe, and it makes relapse more likely. For example, maybe you can face moths only when someone else is around-because in your mind that person can help. Maybe you always carry bug spray with you. The point is, removing these things while doing your exposure allows you to learn to face your fear without the need for any safety, and it makes it less likely the fear will come back. It’s a win-win!

5. Vary it up

By varying the intensity of exposures, it makes it more likely that you will remember everything. Remember that highway analogy? Varying exposure makes it likely that your brain will drive down the highway. Exposure is typically gradual – you move up and up in intensity after you master each part. However, this principle says you should mix it up. This may be hard, but if you put a bunch of exposure ideas in a jar, and pick which one you will do randomly, you will be varying it up!

6. Different Contexts

Simply put, do your exposures in many situations, different times of the day, and imaginal, in-person, and interoceptive (e.g. physical feelings) when possible. It will make your learning stronger and you’re less likely to have your fear return again.

That’s it. The rest of the article goes on to give examples of these principles with cases. If you read it to the very bottom they even give you some little pointers which I think is really helpful.

What I find really interesting here is that it really changes how exposure can be done-these ideas can really help you improve your treatment, both if you’re a therapist or if you’re doing it yourself. In my own interventions, I find that not all of these things can be done all the time, but they are immensely helpful. Once I read this, the way I conducted therapy was forever changed. Sort of like if I played soccer only with my left foot and then learned I could use my right foot too – I’d never go back to only using the one foot! If you are doing exposure therapy, don’t simply wait for habituation, or try to test a hypothesis – do exposure based on inhibitory learning.

That being said, there are some weaknesses here. Much of the research involved here is based on animal studies and very simple human studies (rather than the treatment of complex disorders). As such, whether these strategies actually improve exposure treatment outcomes is a question for future research. And this is a key issue! To me, it makes intuitive sense that these things will help treatment, but without clear research on this, who knows?! At this point, I suspect it’s more likely that some of these ideas apply most to “simple” issues like phobias, because they most closely mimic the way the research has been done. In addition, some of the ideas seem to require a high level of patient “buy-in”, and I can imagine some people dropping out of treatment. For example, facing fears in a more random manner (e.g., point 5. Vary it up) might be really difficult to get a child (or adult) to be willing to do. Really going hard-core on the exposures to violate the expectancy could be really scary. The authors do mention this issue a few times, noting that gradual exposure and explicit intent are key. Finally, and this isn’t a criticism of the paper at all, I think to implement some of these ideas needs a lot of creativity-you almost have to find a way to inject some fun into the process. You have to really think and come up with awesome ways to make these ideas come to life. I’m not saying it’s not possible, I’m just saying that doing this can be really hard, especially depending on the fear and where you work.

Imagine you have a fear. Something really scary to you. It really affects your life. If you put yourself through treatment, which takes a ton of bravery and effort, you want results, and for the results to stick – you don’t want the fear to come back again. And to me, this is why inhibitory learning is key. It unlocks exposure treatment to make it more likely to succeed and less likely that the fear comes back. Overall, this is a really solid article and helps clinical work SO MUCH! You should read it. You really should! It does need some more research to back it up, but I can’t imagine that any of these strategies are harmful as long as full explanations and informed consent are given. In my own work, whenever I do exposure therapy I personally ask myself “am I doing everything I can based on inhibitory learning?” You should too.

Thanks for reading, I hope you found this helpful!


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