Welcome back to the Healing Pain Podcast with Matthew Herbert, PhD

We’re going to be talking about the co-occurrence of chronic pain in PTSD. In the general population, chronic pain and PTSD co-occur in about 10% of the cases. When we look at our population of veterans, 50% to 80% of those are PTSD also have chronic pain. This is an important topic with regard to the care of our veterans as well as for the practitioners who treat them. Joining us to discuss ACT chronic pain and PTSD is Dr. Matt Herbert. Matt is a research psychologist at the San Diego VA and an assistant professor of psychiatry at the University of California at San Diego. His research interests include the study of the biopsychosocial factors related to pain perception and pain disability, as well as my infamous base approaches to pain management. Matt will discuss Acceptance and Commitment Therapy, chronic pain and PTSD, as well as his landmark paper, which can be found in Pain Medicine in 2019 called Acceptance and Commitment Therapy for Chronic Pain: Does Post-Traumatic Stress Disorder Influence Treatment Outcomes?. Let’s begin and meet Dr. Matt Herbert.

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ACT For Chronic Pain: Does PTSD Influence Outcomes? with Matthew Herbert, PhD

Matt, welcome. It’s great to have you here.

Joe, thanks. It’s nice to be here.

I was perusing through some research online, which so many of us do at times, and a study of yours came up, which I think is great and that’s why I reached out to you to talk about it. I know it’s one of the few or potentially even the first study to look ACT for chronic pain with regard to PTSD. Before we get into that study, because everyone’s going to be interested in the outcome and your findings, can you tell us a little bit about your work at the Center of Excellence for Stress and Mental Health?

Thanks for discovering my article. I appreciate that. I like to know people are out there reading the stuff we’re putting out. I did a post-doctoral fellowship at CESAMH. That’s Center of Excellence for Stress and Mental Health. This is one of the newer centers that the VA has organized and this has come out of the more conflicts that we’ve had both in Iraq and Afghanistan. The center is targeted on some of the conditions that are stemming from that, primarily post-traumatic stress disorder and mild traumatic brain injury, traumatic brain injury, things like that. This is a group of researchers that are dedicated to both the treatment as well as the more bio understanding of the conditions. That’s how I got started collaborating with some researchers over there. Now, I’ve found my way into the PTSD research world as a chronic pain researcher.

Tell me anecdotally, what are you seeing within the VA with regard to PTSD? Let’s talk about that first.

It’s the most commonly diagnosed mental health condition that we see, particularly among the younger veterans. It’s a very active PTSD clinic at the San Diego VA as well as all the VAs. From that too, a lot of different researchers are looking at various ways of treating this. This is obviously a complex condition in part because like we’ll talk about, it doesn’t occur in isolation, like many things that come out of this. It’s highly co-morbid with a lot of different conditions, which makes it complex. People are looking at different physical activity interventions for this, treating more cognitively. Some neuropsychologists are working on the cognitive piece that comes with that like myself too, interested in treating chronic pain. What happens when PTSD is a part of the presentation?

There are lots of different types of practitioners trying to help the veterans obviously with PTSD that you see at the VA there. Tell us what the relationship between chronic pain and PTSD is?

Going back decades, the observation came that these two conditions hung together fairly tightly. You see this in civilian populations. Some studies are suggesting anywhere from 10% to 20%, in the veteran population, depending on what cohort you’re looking at, as high as 80%. Researchers started looking at it, “What’s going on with this?” and started seeing commonalities between the two conditions. From this came some models, some theories about this, what some of the more popular ones, the mutual maintenance model, which this was back in 2000, was hypothesized that these common elements are what you see both with PTSD and chronic pain, avoidance of certain types of activities. More of hypervigilance towards certain types of threatening stimuli, whether that be stimuli that might cause pain or some stimuli that might cause some fear response. From that, people started first noticing it’s making a model, theories about what may be explaining this. Since then, there have been several studies supporting these models, not perfectly, but just suggesting that what happens in PTSD might be either a pre-requisite or something that maintains the severity of chronic pain and then it’s a vicious cycle. That chronic pain, what’s maintaining the chronic pain tends to worsen or maintain the PTSD. In a way, you’re stuck and not able to move.

I know there’s more and more interest in this topic, relationship or potentially the bidirectional relationship between chronic pain and PTSD. I want to make sure we mentioned your papers so everyone can google it and take a look at it. Obviously, I’m a researcher, practitioner, so it was in the 2019 Journal of Pain Medicine. The title of the paper is Acceptance and Commitment Therapy for Chronic Pain: Does Post-Traumatic Stress Disorder Influence Treatment Outcomes?. Matt was the primary researcher on that. What’s the rationale of using ACT to treat people with chronic pain and PTSD?

Acceptance and Commitment Therapy or ACT is one of the newer cognitive-behavioral treatments that are out there. Joe, I know that you’re very familiar with this approach. The goal of ACT is psychological flexibility, which refers to this ability to move forward towards valued life directions regardless of the unpleasant internal experiences. These can be things like thoughts, emotions, memories or physical sensations like chronic pain. ACT often gets its title of being a trans-diagnostic treatment. The rationale for that is the same basic therapeutic approach implemented regardless of the condition. It might be tailored to certain conditions, whether it’s for smoking sensation or PTSD or chronic pain. The same treatment elements are all there. It’s helping people be aware of present moment experiences, distance from the thoughts that are going on in my head and the reality that they might be suggesting. They see thoughts as thoughts.

To be willing to accept some of the unpleasantness that might come along, if doing so means you’re moving towards a valued life direction and hopefully drive as much quality of life out of life, given what circumstances you might be dealt with. From that rationale, then it might be that because this is a trans-diagnostic approach, veterans that are in treatment for chronic pain that also have PTSD, they might benefit across the board from the treatment because it’s helping with things that might be also common with some of their post-traumatic stress symptoms. That was the question that was never asked and so the reason why doing this study.

Is that the only psychological intervention that you’re exploring in your work or have you touched on other things like CBT and other types of approaches?

I’ve certainly not only actively studied it. When I first moved to San Diego, I did my graduate work at the University of Alabama at Birmingham, UAB and now I’m a clinical psychologist. That was primarily a CBT approach. Through my own interest in mindfulness, meditation and things like this, I was exposed to ACT treatment at the San Diego VA. It was good timing. This was for the newer treatments that was of interest. From a research perspective, I’ve primarily been within the ACT world as a practitioner. I’ve run different types of groups and done different treatment modalities like dialectical behavioral therapy and cognitive behavioral therapy. From a research standpoint though, I’ve been primarily in the ACT world.

Tell us about the aim of your study. People are interested to know a little bit about it.

Here’s a little bit about this study. This was secondary data analysis. The primary project here was a non-inferiority randomized controlled trial. This was looking at how effective in-person Acceptance and Commitment Therapy for chronic pain was compared to video teleconferencing delivery of ACT. It’s like how we’re doing video teleconference in here. ACT is fairly established in the pain field with good efficacy. The parent study then was saying, “Does this work just as well for delivering it through a telehealth way of delivery?” That’s the setting of the study. That’s another paper that’s out there if readers are interested in publishing in the Journal of Pain. What this study was though is when veterans came in for their baseline assessment, these were all veterans. They got the structured clinical interview for DSM-IV. At that time, it wasn’t quite the DSM-V. Within that, they did a comprehensive workup for post-traumatic stress disorder. That’s how people got put into the PTSD positive groups or PTSD negative groups from this diagnostic interview. This was an eight-week treatment of sixteen minutes, delivered either in-person or via teleconferencing. Participants got our questionnaire battery at baseline, mid-treatment, post-treatments, then at three-month follow-up and six-month follow-up.

Can you tell us a little bit about the type of measures that you were tracking?

The primary outcome was pain interference. For the parent study there, that’s within the ACT treatment studies where it tends to be more interested in pain interference and seeing if the treatment helps pain be less of a barrier in terms of your behaviors. Whether this is regular social functioning with your friends, your work functioning, how much it interferes with your sleep and mood. The primary outcome is we’re interested in how much pain was less of an interference in your life. Other measures, we did measure pain severity of how much pain people were experiencing. Chronic pain acceptance, acceptance of pain being a part of your life, pain-related anxiety, depression symptoms. We also gave a measure of PTSD symptoms to measure the change in PTSD symptoms.

Why is this study important? You measured a lot of things there and this is an important group that we want to try to help, but why is this study important to the greater context of looking at ACT for pain through the lens of PTSD?

It’s through those mutual maintenance models and things that we were discussing before. A lot of this interest came out several years ago, noticing that if you’re an individual that had chronic pain and you also had PTSD, then there’s a much higher symptom severity compared to those that have chronic pain alone or PTSD alone. There seemed to be this synergistic effect that happened there where you see greater levels of pain, greater levels of depression, pain-related anxiety, as well as greater use of substance abuse, more likely to drop out of treatment. You saw that when these two conditions were present, more severity in a lot of different domains. As far as we could tell, no one ever asked the question, “How does an individual like this do in a standalone psychosocial treatment like ACT?” We knew that they might be doing worse in that baseline, but we didn’t know how they would be doing after going through one of these eight-week treatments and not follow-up other symptoms. That was looking at the literature and finding that this wasn’t ever explored and realizing I had the data to look at this. That was the motivator to get going on this.

I want to clarify for people who are not as well-versed in trauma. Just to clarify for both practitioners and the public, you’re not saying that everyone with chronic pain has PTSD so to speak.

No, of course not. In some, like in the civilian, more broad samples, we’re talking about maybe 7% to 8% of a co-occurrence. When you look at them like a veteran population where the incidents of something like PTSD is even higher, you also see the co-occurrence of it being even higher too. When we do studies, and Joe, I think you notice of doing studies, we often are looking at means compared to other means. We try to get at the average person, but these are all individuals with their own different contextual things going on in life and difficulties. You’re not suggesting anything about a given person, but also acknowledging that within the populations that I do work in. You do see these two things going together. Typically, in different domains, it’s the worse severity.

Thanks for that clarification because there’s confusion and potentially a myth out there that if you have chronic pain that has been resistant to treatment, that potentially you had a trauma somewhere, whether it was recent or in earlier life and that is the reason why your pain is persistent. There are definitely people that fall through the cracks or not being treated for trauma. It doesn’t mean that everyone with chronic pain has a significant history of PTSD. I think that those are important because I get a lot of emails from people with pain looking for the solution. That’s the reason why I wanted to talk about that. Within the frame of trauma, in your study you talk about re-experiencing avoidance and hyperarousal. I think that was part of the PTSD, the way you measured the symptom severity. Can you talk about those three things a little bit, re-experiencing avoidance and hyperarousal and what they mean?

Clinically, to get a diagnosis of that post-traumatic stress disorder, there are one or more events that occur to an individual, whether there are some life-threatening elements to it. It also could be something like a serious injury or a sexual violation, something like that. This traumatic event happens. From the DSM-IV standpoint, they looked at a cluster of three different symptoms. The DSM-V has added another cluster. Historically speaking, the three cluster of symptoms that we’re looking at to meet diagnostic criteria were these re-experiencing symptoms. These were things like having flashbacks, nightmares, things like this. The avoidance cluster was symptoms that we’re trying to avoid certain types of thoughts or avoiding certain places. People that were reminders of the traumas, that cluster.

The hyperarousal cluster is things like feeling on guard, being aggravated and things like this. These are all within the different PTSD checklists, questionnaires that are often used to help make this diagnosis. We’re looking at these three clusters and seeing if this interferes with your social, occupational functioning and if these symptoms have lasted for one month or longer. Broadly speaking, that’s how the diagnosis of PTSD happens. Clinically, I’m not a PTSD expert. I work closely in the PTSD world. That’s why in the context of this research study, we gave that PTSD checklist, that PTSD questionnaire and I was interested in if the ACT treatment would change any of these different clusters.

It’s because that avoidance that you mentioned and the hyperarousal when I read through those questions in your study, a lot of them are almost very ACT-informed questions if you will. It almost makes you think with regard to ACT, there’s a lot of exposure in ACT. Helping people open up to some of the things they’re avoiding, even helping them open up to the uncomfortable sensations in their body that are linked to that sympathetic arousal. I look at that and that is good to help inform someone’s treatment. Tell us what the main findings of your study were.

We looked at two different ways of looking at the data. I was interested in first compared to baseline levels when people entered the study. How much improvement were we seeing at post-treatment and where the difference is between the two groups: the PTSD positive and PTSD negative groups. The second question was, how are the participants looking at six-month follow-up compared to baseline levels? How well do we do in treatments and then how well are those treatment gains maintained over the six-month period? What we found there is between the two groups, these are the PTSD positive, PTSD negative groups, there were no significant differences between baseline and post-treatment levels. Rather, regardless of whether what group you fell into there, we saw significant improvements across the outcomes. That was pain interference, pain severity, pain acceptance, pain-related anxiety and levels of depressive symptoms.

There was a non-statistical trend for pain acceptance for those with PTSD to show less increases in chronic pain acceptance versus the PTSD negative group. It wasn’t statistically significant, but there was what some signal there. When we looked at the baseline, the six-month group, looking at the maintenance, the treatment gains, that’s where we found that those that have PTSD, they did not show as much long-term improvement in depression symptoms relative to those without the PTSD diagnosis, based on the diagnostic interview that we gave them. In the other outcomes, they still showed significant improvements. Still compared to baseline levels, people in that group are still showing improvements in pain interference, pain severity and also of chronic pain acceptance too.

That depression piece is interesting though and it’s worth us talking a little bit about because there is that bidirectional link between depression and chronic pain. Any reason that you can hypothesize about why at the follow-up, you’re talking about six months after this study, why the depression may have been a little bit resistant to treatment? It was significant and that lasted after post-treatment?

It was a trend. We can talk about P values, but with pain-related anxiety too. That was also not statistically significant, but the trends were also suggesting that those with PTSD did not have as much improvement relative to baseline as those without PTSD. Both with anxiety and depression, which they themselves are tightly interrelated. You talked about the relationship between PTSD and depression, which is very tightly related. In some of the PTSD researchers that I work with, they’ll say you can’t talk about PTSD without depressive symptoms because there’s so much overlap there. I talked before about that the three clusters, they add a fourth cluster for DSM-V. That fourth cluster was negative affect. Even hitting upon a lot in acknowledging that PTSD often comes with these depressive-like symptoms that come with a condition. Looking at the data, the data is what it is and interpreting that data, our belief was that while ACT for chronic pain, there was evidence that this is helping people with chronic pain that also didn’t have PTSD and was helping a lot of the pain domains.

When it comes to the depression domain, because there’s this depression/chronic pain relationship, but it might be that depression/PTSD relationship, it doesn’t have anything to do with chronic pain. Rather there are a lot of pieces that are independent or chronic pain within that. That the treatment just wasn’t either powerful enough, long enough, well-integrated with elements of more PTSD-focused treatments to see these gains maintained long-term in depression. We also looked at measures of PTSD symptom severity and we saw something pretty similar among those that had chronic pain and PTSD. We saw that at post-treatment, there was a reduction on our measure of PTSD symptoms severity. We were seeing reductions in those three, like hyperarousal, the truth of memories, intrusion and the avoidance clusters. Those two also not maintained that six-month follow-up.

Our interpretation was in the short-term it seems like this app that’s focused on chronic pain, it does alleviate symptoms on both PTSD and depression. Long-term, we’re not able to maintain those gains. We felt like maybe there needed to be a little bit more PTSD-focused intervention, whether it be either longer or more directed towards PTSD itself. Maybe integrating more PTSD specific exposure in there, like the hallmark of prolonged exposure, one of the leading evidence-based treatments for PTSD in there to maximize the effectiveness of the intervention.

I noticed when I was reading through your paper, I’m familiar with the ACT for pain protocol that you use in this study where people are getting about an hour for eight weeks. I know that protocol is not very heavy on pain exposure or exposure in general. That was one thing I was like, “This is interesting,” that one piece. There is exposure in every part of ACT at almost every process. There are certain trends toward more and more exposure, especially with regard to certain populations, anxiety being one, chronic pain being one and PTSD being another. The other thing that came to mind is with protocols, there’s an ACT for pain protocol, depression protocol, PTSD protocol. I know these are the kinds of things that researchers spend their entire lives and time studying. Do you think if you took the same group and applied an ACT for depression protocol with the same measures, would you potentially have received? This is all just talk, but do you think the same pain interference would have improved but potentially the depression factors, the measures would have persisted for a longer period of time?

Potentially. A lot of the outcomes that we measure tend to be pretty highly correlated with each other, even themselves. It does in some ways, seem like improvement in one domain certainly goes across improving in the other domain. I think that’s on us as researchers to find better ways of capturing important constructs that are related to what we want to see happen in treatments. Although it’s trans-diagnostic treatment, but then it’s like, “We see ACT for depression, ACT for chronic pain, ACT for anxiety.” Some of that is within a larger medical context. These are seen as discreet conditions that they need to be these discreet clinics that get treated in.

If I’m an individual and a doctor tells me that I have depression, it’s like, “I want to go get treated for my depression.” It all relates like that too. One thing I’d be interested in is as we see some movement here. Do we have more trans-diagnostic clinics where we’re getting more treatments that are trying to cut across a lot of different things? Is there any way of addressing things that an individual may be experiencing? For some people, it might just be chronic pain. For someone else, it might be pain and depression. For someone else, that might be substance abuse and depression. Is there a way that we could help people deal with this? The challenge of making the desired behavior change, which is hard for every human being. Trying to get at that so we can start helping people try to live more of a meaningful life as much as they can. This is the spirit behind ACT, but ACT is operating in a medical system environment that we can’t just change overnight.

When you think about psychological flexibility and knowing that it’s transdiagnostic, but yet you mentioned our medical system and the way research is set up, we still put things in silos. We wonder, as clinicians, is this the best way to care for someone? Sometimes it is and maybe sometimes it’s not. Humans are very varied and they need lots of different types of interventions. What’s been some of the feedback that you’ve received from your colleagues about this study?

It’s pretty positive. I was at SBN, Society of Behavioral Medicine and I gave a talk on this study as well as some of the findings that I had in regards to medications that people were using and seeing how those medications also played out. There’s a definite interest. A lot of people attended that talk. PTSD is so known. It went from years ago as a relatively unknown condition and now when I tell people that I work at the VA, they go, “Do you treat PTSD?” It turns out I’m involved in it, but there’s a lot of interest I think because of the wars that we’ve had in Iraq and Afghanistan. There were different types of combat. We had a lot the medical care. We saw a lot of veterans returning that has a lot more veterans who are surviving conflicts that twenty years ago maybe they would not have. With that, this became much more of an acknowledged condition that was going on. That was a good thing because we needed that. From that, there has been some interest. It’s still relatively newer paper that came out. I’m glad that we did a study and shed light on this and get people to keep on talking about this important relationship between these two.

You mentioned something, which I held it for a moment. This is part of a larger study where you looked at ACT in-person versus ACT provided via the internet, I believe. Can you give us a little view into what’s more effective potentially?

That paper was my first time delving into these types of analyses. That’s called the non-inferiority approach. You see this a lot in medications where let’s say a drug company had a patent on a drug and then they’re going to make more of a generic. That point they don’t want to say, “Is this drug better than this drug?” They don’t want to say, “Is this drug no worse than this drug by a certain margin?” You’re almost testing a null hypothesis in a way where you want to see if these things are equivalent and that’s what we’re doing with the in-person versus the teleconferencing delivering of it. As in-person works here, does teleconferencing work right around there? For the most part, we found it dead in terms of the primary outcome being this measure pain interference. It was, as I say, non-inferior towards that.

A couple of the other outcomes fell outside of that non-inferior range, but not statistically significant. The two main findings from that were, one, you were more likely to drop out in the treatment if you’re getting a video teleconferencing modality. That was interesting. I think in-person, we don’t know why. They did different measures of satisfaction, but maybe it’s also because the people that dropped out, they didn’t come back to fill out those measures. People are more likely to drop out in the video teleconferencing condition. We had a measure of looking at activity levels and those that had the in-person delivery, at six-month follow-up, they were showing greater improvements in terms of activity levels versus those in the in-person condition.

The main takeaway there was in terms of the primary outcome the study was powered to look at and things like that, it did seem to do about equivalent. Certainly, that’s your only option of delivering ACT for chronic pain. Definitely do it. There did seem to be some advantages with in-person and not being the potentially less dropout and some benefits long-term with in-person relative to the video teleconferencing. In terms of this study, I was interested if veterans that have chronic pain and PTSD, they sometimes respond differently to the video teleconferencing versus the in-person. I didn’t find much there. We’re dealing with small sample sizes in those groups, so you have to be careful of your interpretations. Interestingly, the means suggested that at mid-treatment, the in-person might have had a bit of a benefit over the video teleconferencing but at post-treatment six-month follow-up there wasn’t anything detecting. These are small sample sizes so I don’t fully trust those means, but nothing indicative at this point.

Thanks for sharing a little bit of that other study with us as well. Matt, it’s been great having you. I appreciate your time and all the work you’re doing with ACT, chronic pain and PTSD and everything else that is related to it. If people want to learn more about you and the work that you’re doing, how can they find you?

I am still a faculty member at the VA San Diego Healthcare Center. I am still involved with CESAMH, that’s the Center of Excellence for Stress and Mental Health. You can see my bio there and that will have my contact information. If you want to contact me, I would be happy to answer emails, answer questions.

I want to thank Matt for his time. Make sure you share this with your friends and family on your favorite social platform.

Thank you.

Important Links:

• San Diego VA
• Matt Herbert
• Acceptance and Commitment Therapy for Chronic Pain: Does Post-Traumatic Stress Disorder Influence Treatment Outcomes?
• Center of Excellence for Stress and Mental Health
• Society of Behavioral Medicine
• Matt Herber’s bio in CESAMH
• https://www.NCBI.NLM.NIH.gov/pubmed/30602034
• https://www.CESAMH.org/clinicalunit/matthew-herbert/
• https://Profiles.UCSD.edu/matthew.herbert

About Matthew Herbert, PhD

Matt Herbert, Ph.D., is a research psychologist at the San Diego VA and assistant professor of psychiatry at the University of California, San Diego. His research interests include the study of biopsychosocial factors related to pain perception and pain disability, and mindfulness-based approaches for pain management.

The Healing Pain Podcast brings together top minds from the world of pain science and related fields to discuss the latest findings and share effective solutions for persistent pain.

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