July 22, 2020

Using the biological aspects of mental health to provide psychiatric treatment of patients with refractory chronic pain with Dr. Dmitry Arbuck

47 minutes

Dmitry M. Arbuck, MD, joins host Lorenzo Norris, MD, to discuss ways psychiatrists can help patients with treatment-resistant chronic pain.

Dr. Arbuck is clinical assistant professor of psychiatry and medicine at Indiana University, Indianapolis. Dr. Arbuck also serves as president and medical director of Indiana Polyclinic, a multispecialty pain management facility, and is an associate editor of Current Psychiatry.

Both Dr. Arbuck and Dr. Norris disclosed having no conflicts of interest.

And do not miss the “Dr. RK” segment, where Renee Kohanski, MD, discusses part 2 of her examination of the constructs of medicine.

Take-home points

Acute and chronic pain are mediated by different mechanisms and therefore must be treated differently. Acute pain is caused by tissue damage leading to nociception, and it should heal. Chronic pain is the chronification of acute pain and more of an emotional state with sensations of pain without clear tissue damage.
Many neurotransmitters are involved in pain, including dopamine, serotonin, norepinephrine, and the opioid system.
- The levels of neurotransmitters will change as the pain (emotional and physical) thresholds change.
- When patients with borderline personality disorder cut themselves, dopamine increases, and the patients, in turn, feel better. Likewise, when patients with PTSD reexperience negative events, this causes an increase in dopamine to protect against stress.
Psychiatrists are particularly well positioned to help those with chronic pain because trauma and emotions are central to the perception of emotional and physical pain. Emotional trauma also influences the severity and chronicity of pain.
Currently, pharmacogenetics are more of a general guide for clinicians than specific practice guidelines. But they can inform patients and physicians about drug metabolism and expression of receptors in difficult-to-treat patients.

Summary

Chronic pain can be understood as emotions colored by nociception, while acute pain is the tissue damage and subsequent nociception causing pain. Opioids suppress the nociception of pain and are appropriate in acute pain. However, opioids should be used only in the normal time of healing in acute pain. If their use is extended, opioids can cause hyperalgesia, thus worsening chronic pain.
Many forms of chronic pain, such as fibromyalgia and chronic back pain, do not have tissue damage. The sensations of physical pain and the compounding emotional pain are mediated by central pain sensitization. The theory behind central pain sensitization helps explain why medications such as SSRIs, serotonin-norepinephrine reuptake inhibitors, and antipsychotics can come into play in chronic pain treatment.
In some patients, there can be dopaminergic hyperactivity in chronic pain. Dr. Arbuck conceptualizes dopamine as a defensive neurotransmitter. Dopamine is secreted in response to fear and can result in a physical response, such as weakness in the legs, but it also leads to emotional consequences, such as dissociation. Dopamine is also secreted with emotionally painful stimuli, such as trauma, so an event such as a sexual assault that results in a physical and emotional injury may produce substantial dopamine secretion. When the defense becomes chronic, excessive dopamine secretion can be pathological.
Pharmacogenetics inform clinicians about a patient’s ability to benefit from medications by looking at the presence of specific alleles for enzymes that metabolize medications and for receptors upon which medications act. Currently, Dr. Arbuck uses pharmacogenetics in specific indications, such as for patients with a seemingly treatment-resistant condition or with excessive adverse effects from medications.
The pharmacogenetics results are meant to help physicians and patients understand the body’s role in medications.
Psychiatry needs to look more into the medical aspects of mental health, and training in psychiatry needs to be more biological in nature.

References

Arbuck DM. Current Psychiatry. 2020 Jan;19(1):25-9;31.

Clauw DJ. JAMA. 2014;311(15):1547-55.

Nijs J et al. Expert Opin Pharmacother. 2014 Aug;15(12):1671-83.

Dale R and Stacey B. Med Clin North Am. 2016 Jan;100(1):55-64.

Show notes by Jacqueline Posada, MD, who is associate producer of the Psychcast and consultation-liaison psychiatry fellow with the Inova Fairfax Hospital/George Washington University program in Falls Church, Va. Dr. Posada has no conflicts of interest.

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