Thursday, February 21, 2013

New Studies Confirm – and Contradict – Conventional Wisdom on Chronic Pain


New Studies Confirm – and Contradict – Conventional Wisdom on Chronic Pain
by Ian McLoone

- Chronic pain patients have long been told it’s all in their heads. Well, a team at McGill University just submitted more proof. The researchers, led by Prof. Laura Stone, found that injuries resulting in chronic pain are associated with epigenetic changes in the brains of mice which can be observed 6 months after the date of injury. These heritable changes, called DNA methylation, have far-reaching consequences across the entire genome and can impact behavior and well-being – but were also shown to be reversible. “The implications of epigenetic involvement in chronic pain are wide reaching and may alter the way we think about pain diagnosis, research and treatment,” the authors say. Future considerations for treatment will likely include behavioral and pharmacological interventions that focus on reversing DNA methylation in brain.

- Think all addicts make risky chronic pain patients? Think again. For decades, the conventional wisdom has told us that addicts and alcoholics are constitutionally incapable of managing chronic pain with the help of opioid pain relievers – no matter what their drug of choice had been. However, a recent study suggests that this isn’t necessarily the case, and that risk factors for opioid misuse are dynamic and complex.   

The study, published this January in the Drug and Alcohol Dependence journal, found that the trait most significantly associated with risk for prescription opioid misuse was “pain catastrophizing” and that, “current substance use disorder [SUD] status was not a significant predictor [of risk].” While it’s been shown elsewhere that simply being prescribed opioids constitutes a significant risk factor for abuse and misuse behaviors, this study seems to suggest that by screening for past or current SUD, we may be missing the point.

Dr. Carlton Erickson, PhD, director of the Addiction Science Research and Education Center, tells me it’s an issue that’s “currently being hugely debated across the nation…mainly [by] pain medicine physicians and addiction medicine physicians.” Much like Dr Willenbring, he stresses the importance of an integrated and comprehensive approach to working with such patients and suggests ensuring access to, “a team consisting of an addiction medicine specialist, pain management specialist [and] counselor…who can guide the treatment while minimizing the likelihood of” misuse. On a related note, there was news last year that chronic pain patients on opioid therapy can be successfully converted to buprenorphine. Specifically, patients on a morphine equivalent dose of 100-199 mgs seemed to fare better than those on higher doses.

- Does the color of your skin affect your chronic pain treatment? A new study suggests it does. Leslie R Hausmann, PhD, led a team of researchers from the VA Pittsburgh Healthcare System to investigate whether racial disparities existed in the follow-up and monitoring of patients who were prescribed opioid medications over a two-year period. In adjusted comparisons, they found black patients were less likely to have their pain documented than white patients, less likely to be referred to pain specialists, and more likely to be referred to a substance abuse assessment. Also, among those patients who had at least one drug test, black patients were subjected to more drug testing than their white counterparts. Among the report’s conclusions, the authors suggest that, “Addressing disparities in opioid monitoring and follow-up treatment practices may be a previously neglected route to reducing racial disparities in pain management.”

Ian McLoone is a graduate student at the University of Minnesota’s Integrated Behavioral Health program, a Graduate Research Assistant at the Minnesota Center for Mental Health, as well as a clinical intern at Alltyr, Inc.



2 comments:

  1. I found the info about "pain catastrophizing" very interesting.

    "The study, published this January in the Drug and Alcohol Dependence journal, found that the trait most significantly associated with risk for prescription opioid misuse was “pain catastrophizing” and that, “current substance use disorder [SUD] status was not a significant predictor [of risk]."

    I'm wondering if there is any research pertaining to opiate dependence and a relationship between withdrawal catastrophizing and relapse rates. Anecdotally, I have seen a relationship between what can best be termed "opiate withdrawal catastrophizing" and length of reported withdrawal symptoms and ultimately struggles with maintained abstinence.

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  2. Matt, I would think the extent of opioid withdrawal catastrophizing is associated with chronicity of opioid dependence, or the extent that previous withdrawals were managed/not managed.

    The chronic pain article was interesting. A paradigm shift is occurring in pain medicine involving a mechanistic approach targeting alteration in central processing, descending inhibitory pathways, peripheral sensitization, etc. This approach departs from the trad. approach typified by the WHO "pain pyramid" (WHO 1996) where analgesic potency is escalated until pain relief is felt, and offers a real chance to target pathophys. mechanisms. For example, the NMDA antagonist ketamine has shown efficacy in several chronic severe pain conditions, theoretically maintained (in part) by glutamate receptor activation which amplifies pain signalling and suppresses normal pain modulatory mechanisms. Chronic pain is now viewed as a distinct pathologic condition of peripheral and central alteration and not merely a prolonged extension of nociceptive pain from the original pain-inducing injury or disease.

    Mark Edmund Rose, Licensed Psychologist

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