A potential difficulty, but also an opportunity, relating to using neuroimaging evidence in legal cases arises from the difficulty brain researchers have in separating emotional and physical pain. We know that pain and emotion are tightly linked. In fact, “emotion” is in the very definition of pain. The IASP definition of pain is: “An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.” Yet, the legal system deals with “physical” versus “psychiatric” versus “emotional” pain in different ways.
Chronic pain is associated with anxiety, depression, and stress. These factors can exacerbate the pain, and pain can exacerbate them. Pain’s sensory and emotional components connect in a “feed-forward” cycle. It may not be possible to entirely separate the sensory and emotional components of pain, biologically or experientially. But it might be necessary for the purposes of legal cases, as important areas of law create sharp distinctions between physical and emotional, or body and mind.
Chronic pain patients often have varying degrees of heightened levels of anxiety, stress, depression, cognitive dysfunction, and poor sleep. While these tend to be subclinical levels, in some cases they may be full-blown disorders of their own. These chronic pain comorbidities, such as depression and some types of chronic pain, can occur in up to 50% of patients. These comorbid conditions can synergistically increase suffering and decrease quality of life.
Neuroimaging does not distinguish chronic pain patients from healthy controls in terms of activation of the so-called pain matrix – the pattern of brain activation associated with acute experimental pain. Instead, what is becoming clear from multiple lines of evidence is that chronic pain is associated with increased emotional reactivity and decreased reward processing. For example, reward processing circuitry has been shown to be abnormal in chronic low back pain (see also here) and in fibromyalgia patients (see also here). There is also disruption of cognitive networks in chronic pain (see also here).
What role might neuroimaging take in distinguishing emotional and sensory aspects of chronic pain? Is there a meaningful distinction between emotional and physical pain, or does one always involve the other? What consequences might these distinctions have in legal settings? And how might neuroimaging inform legal doctrines and regulations, or have a useful role case-by-case? These are challenging questions. How we frame and investigate them may have important consequences for the scientific understanding and clinical treatment of pain conditions. It may, as well, affect the ways that bodies of law recognize and compensate different kinds of pain.
Earlier posts in this series:
- Pain on the Brain: A Week of Guest Posts on Pain Neuroimaging & the Law, by Amanda C. Pustilnik
- Pain-o-meters: How – and Why – Should We Develop Them?, by Karen Davis
- Some Optimism on Brains, Pain & Law – Let’s See What We Can Achieve, by Martha Farah
This post is part of the series on pain, brain imaging, and the law sponsored by the Center for Law, Brain & Behavior at Massachusetts General Hospital, the Petrie-Flom Center, and Harvard University’s Mind/Brain/Behavior Initiative. Contributors participated in the conference Visible Solutions: Now Neuroimaging Helps Law Reenvision Pain. For inquiries, please contact the organizer Amanda C. Pustilnik (@apustilnik on Twitter).