Dr. Dubois is professor of anesthesiology at the New York University (NYU) Medical School and director of the NYU Pain Program in New York City.

Disclosure: Dr. Dubois receives grant support from Archimedes, Pfizer, Purdue, and Wyeth.

Please direct all correspondence to: Michel Y. Dubois, MD, Director, NYU Pain Program, 317 E 34th St, Room 902, New York, NY 10016; Tel: 212-263-7316; Fax: 212-685-5365; E-mail: Michel.Dubois@nyumc.org.

 


 

 

Immense progress in pain research in the last 40 years has led to improved diagnosis and treatment of pain patients. Since Melzak and Wall’s1 landmark gate theory published in 1965, overwhelming evidence, from both basic science research and clinical investigation, has replaced the simplistic “wire concept” of pain transmission with new and more subtle pathophysiologic mechanisms. One of the main findings has been that, whereas acute pain can be related to tissue injury, and pain is usually a symptom of this injury, lasting chronic pain has been shown to represent a different condition which is not related to peripheral nociceptive input but represents a disease state of its own. This disease state is created by neural plastic changes of the nervous system usually referred to as “sensitization.” Because it is a disease involving the nervous system, it is not surprising that chronic pain may be associated with significant psychological effects leading to psychopathology.

Conditions such as major depressive disorder (MDD), anxiety, posttraumatic stress disorder, substance abuse, somatoform disorder, and personality disorders have all been shown to be present at a significantly greater rate in chronic pain patients than in the general population. For example, MDD has been found to be present in 45% (current rate) and 65% (lifetime rate) of patients with chronic low back pain, while MDD rates are 5% (current rate) and 17% (lifetime rate) for the entire United States population.2

Although it has been suggested that patient characteristics, predating the onset of chronic pain, may influence the onset of psychopathology, no single model explains the relationship between chronic pain and psychopathology in all patients. For example, MDD, when shown to precede a chronic pain condition, is usually exacerbated by chronic pain. Some patients have developed MDD as a direct consequence of chronic pain, while others develop the two conditions concomitantly. Even if the “chicken and egg” dilemma cannot always be solved, it has been found that treatment of a psychiatric disease in chronic pain patients leads to more rapid improvement in pain complaints, and, vice versa, treatment of pain improves psychopathology. Therefore, it is no surprise that therapeutic modalities, used separately in pain medicine and psychiatry, are in fact overlapping. It is also logical that support and interaction are often needed between the two specialties when taking care of chronic pain patients.

This issue of Primary Psychiatry presents papers from mental health professionals, all with extensive experience diagnosing and treating patients with chronic pain.

First, cognitive-behavioral treatments and psychotherapy are now routine modalities for the treatment of chronic pain. Allen Lebovits, PhD, describes the wide variety of techniques used as well as their indications, outcomes, and limitations. He stresses the importance of public and professional education on psychological evaluation and treatment in chronic pain in order to alleviate existing barriers that prevent patient access to those treatments, shown to be highly effective in many cases.

Next, Matthew B. Smith, MD, examines the interplay between psychopathology and chronic pain, describing the psychiatric conditions believed to be caused by chronic pain, including pain behaviors, personality changes, and syndromal disorders. In cases where pre-existing psychopathology appears to be greatly aggravated by chronic pain, predisposing factors and the relative contribution of each condition need to be carefully assessed. Clinical encounter with the patient, often difficult but always essential to achieving a precise diagnosis and allowing a more efficient treatment, is particularly emphasized.

Michael R. Clark, MD, MPH, describes the psychopharmacology of pain in detail. Many medications used to treat pain, especially neuropathic pain, are, in fact, commonly used in psychiatry. Since the neurochemistry of pain has been found to be very similar to the neurochemistry of, for example, MDD (ie, common receptors and mediators involved), it is not surprising that the same medications have a beneficial effect on both pain and specific psychiatric diseases. This serves to underline the importance of the psychiatrist contributing to the treatment plan of chronic pain patients through interdisciplinary modalities.

Finally, William Breitbart, MD, FAPM, FAPA, and Christopher A. Gibson, PhD, applying wide-ranging experience in the psychiatric aspects of the terrible ordeal of cancer pain on patients, lay out the problems and solutions encountered in caring for these patients. Although cancer pain has many of the same characteristics as chronic non-cancer pain, it is usually the direct result of aggressive tumor-induced tissue damage, creating a different clinical context. Management of cancer pain, therefore, requires unique skills and competence. Breitbart and Gibson’s approach to pain management in cancer patients gives a good description of a multi-modality treatment, which is the only proven solution to providing optimum care for these patients.

The role of psychiatry in the diagnosis and treatment of the chronic pain patient is established.3 Psychological and psychiatric expertise is often required in order to optimize the treatment of such patients. This ideally occurs within an interdisciplinary evaluation and treatment arrangement where both psychological and psychopharmacologic modalities are routinely available and used.

Since psychiatry plays a growing role in the management of chronic pain patients, training requirements in psychiatry have been established by the Accreditation Council for Graduate Medical Education as part of the pain medicine fellowship curriculum.4 The American Board of Psychiatry and Neurology now offers a sub-specialty certification in pain medicine. Because of the recognition during the last few years that pain is a sensation influenced by cognitive, emotional, and psychological factors, an “irreversible symbiosis” has been established between pain medicine and psychiatry. This alliance is here to stay and to develop. PP

References

1. Melzack R, Wall PD. Pain mechanisms: a new theory. Science. 1965;150(699):971-979.
2. Dersh J, Polatin PB, Gatchel RJ. Chronic pain and psychopathology: research findings and theoretical considerations. Psychosom Med. 2002;64(5):773-786.
3. Sharp J, Keefe B. Psychiatry in chronic pain: a review and update. Curr Psychiatry Rep. 2005;7(3):213-219.
4. Leo RJ, Pristach CA, Streltzer J. Incorporating pain management training into the psychiatry residency curriculum. Acad Psychiatry. 2003;27(1):1-11.