New Research Shows Links Between Pain, Trauma, and Opioid Use

Our research team has a new study out this week, written by one of my nursing honors students, Linda Driscoll Powers. The study looked at questionnaires filled out by 476 people participating in a treatment program for adults with opioid use disorders (OUD) in rural parts of Colorado, which was funded by the Colorado legislature as part of its statewide opioid response plan. Linda is especially interested in understanding people's history of trauma and abuse, and how that might affect their current experiences of illness or treatment. Many health care professionals are starting to pay attention to these things, adding scales like the ACE (Adverse Childhood Experiences scale) or principles of trauma-informed care to their practice. Linda's hypothesis was that people with a history of trauma would have more trouble with symptoms that predispose them to opioid use, resulting in a higher percentage of patients with trauma histories among people with OUD than in the general population. Previous work done in the Kaiser Permanente insurance system had suggested that adverse childhood events could account for two-thirds to half of all serious problems with drug use.

It's hard to get exact estimates of how many people have a lifetime history of abuse, because many people don't like to talk about these experiences. Health care providers also fail to ask their patients about trauma history, so many problems of this type are never documented in people's health care records. However, the World Health Organization estimates the incidence of childhood physical abuse at around 25%, and childhood sexual abuse at around 13% (for men) or 20% (for women). Rates of adverse childhood experiences were substantially higher in our sample of people with OUD, with 23% reporting lifetime sexual abuse, 43% reporting physical abuse, and 58% reporting psychological or emotional abuse. There weren't any differences for men versus women in our sample.

The most interesting finding of Linda's study, however, is that people with a history of abuse -- physical abuse in particular -- reported higher levels of current physical pain. Pain is of course the main reason that people start to use opioid medications, usually beginning with a legitimate prescription from a doctor for pain-reducing drugs like oxycodone (Oxycontin), hydrocodone (Vicodin), or codeine. Sometimes people move to heroin use or other illegal forms of opioids after they can't get prescription painkillers from their doctor anymore. Physical pain, then, can be the trigger that sets in motion a cascade of problems resulting from opioid use. Linda found that people with a history of physical abuse were significantly more likely to have a "chronic pain" diagnosis in their medical record, even in a group of people with OUD who all probably experienced pain at some point. And on a question that asked "what is your current level of pain" using a 5-point scale, people who had a history of childhood physical abuse said that they had more physical pain right now than other people with OUD who didn't report a childhood history of abuse. That's a pretty dramatic and lasting effect for events that happened many years previously.

It might be tempting to say that the pain experienced by people with a history of abuse is "all in their heads," but in fact pain exists nowhere except in a person's head. The only way to know that someone is in pain is for them to tell you so, which is a perennial challenge of treating pain in people with speech problems, infants, or animals. (In those cases, people instead try to infer the experience of pain from someone's behavior). Some people certainly do have higher pain tolerance than others, and the perception of pain can change over time. But if someone says they have a high level of pain, regardless of what the cause might be, the only reasonable course of action is to believe them -- that is, in fact, their experience of pain. The fact that pain is experienced individually and can't be shared is actually part of what makes it feel painful to many people -- the experience of pain can be isolating in a world where other people seem to be feeling fine.

I have written before about how trauma can change our perceptions of the world around us. People with a history of trauma might have nervous systems that are more finely-tuned to detect threats, especially when the past trauma involved physical harm, and the current situation seems to involve a threat to physical health and well-being. Besides the intensity of pain, it's also possible to rate factors like its duration or level of interference with life, and we didn't ask about those things in the current study. And people may differ in how they interpret the meaning of pain (sometimes called "pain catastrophizing"), for instance whether they think that pain means they are suffering irreparable harm or that they need to stop doing what they are doing immediately. It seems likely that a history of trauma could affect some of these aspects of pain perception, which might filter through as part of people's response to the one question that we asked them in the current study about pain intensity. 

Some of the new interest in trauma-informed care among health care professionals has to do with the long-term effects of the COVID-19 pandemic, and the changes that we have seen in people who experienced different forms of more recent trauma in their lives. Do the results of Linda's study mean that people traumatized over the past 2 years are going to feel more physical pain, use more opioids, and end up needing treatment for drug use soon? No, these results don't take us that far. They are at this point limited to childhood experiences of trauma, which for developmental reasons might have more lasting effects than adult experiences do. They were based on a relatively weak measure of trauma history, a single yes/no question about each of 3 different types of abuse. And although they showed that people with a trauma history experienced more physical pain, they didn't necessarily show that people with more pain are more likely to over-use opioids (everyone in this particular study was already diagnosed with an opioid use disorder, so we just can't comment on whether pain predisposed them to that type of problem). 

What these findings do suggest is that clinicians should take people's trauma histories more seriously. Childhood trauma seems to in some way re-wire or re-focus the Intuitive mind, so that people in adulthood report experiencing pain more intensely, which might in turn make it harder for them to avoid or recover from problems related to OUD or other forms of addiction.