Presentation of pain may harbor depression

When a patient -- whether in Beijing, St. Louis or anywhere else -- presents with a persistent pain in the neck or the back, that patient may also have a mental illness that needs attention.

Experts hope that new evidence supporting this universal connection will lead to a greater recognition of it as well as the identification of the biological factors driving both problems. And these factors could ultimately become novel treatment targets.

For instance, a study published online last month in the journal Pain found the increased risk of an anxiety, mood or substance use disorder conferred by chronic neck and back pain is a worldwide phenomenon not limited to industrialized nations.

"There's the idea that mental health and pain problems are by-products of modern culture. This suggests that the phenomenon is more universal," said Michael Von Korff, ScD, one of the authors and a senior investigator at Group Health Cooperative's Center for Health Studies in Seattle.

This finding is the most recent from the World Health Organization's World Mental Health Survey Initiative. Researchers asked 85,088 adults in 17 countries in Europe, North and South America, the Middle East, Africa, Asia and the South Pacific about their experiences with chronic back and neck pain.

In the survey, mental health was assessed using the Composite International Diagnostic Interview. Pain rates varied from country to country, but the association between the pain and mental health problems was consistent. Chronic pain increased the risk of a mood disorder by 130% and an anxiety problem by 120%. The link with alcohol abuse or dependence was less, with an increased risk of 60%.

The connection between pain and various mental health issues has been long recognized in developed nations. It also has complicated pain treatment which, even by itself, is not simple.

"We think of pain as a sensation, but really it's an emotion," said Scott Fishman, MD, a past president of the American Academy of Pain Medicine and chief of the division of pain medicine at the University of California, Davis. "It's an alarm that grabs your attention. When it's on, you cannot do anything else. You have to respond, and that's as true in Japan as it is in Africa as it is in the United States."

In order to improve treatment, the AMA's Council on Science and Public Health published a report on neuropathic pain in June 2006. The AMA also supports more effective promotion and dissemination of educational materials for physicians on prescribing for pain management.

Experts say that not all patients with chronic pain have comorbid mental health conditions, but the link appears common and important enough to have many urging the increased incorporation of mental health assessments when considering treatment options.

"It's something of a loose association. It doesn't mean everybody has it, but it does warrant investigating whenever we have a pain patient," said Frederick Burgess, MD, PhD, immediate past president of the American Academy of Pain Medicine and a clinical professor at Brown Medical School in Rhode Island. "If you have patients with depression, many times your best treatment for pain is to treat the underlying depression and then focus on the pain problem."

But while this link is recognized, how it functions is not well understood. Some specialists hope this line of research will further elucidate its nature. "You wonder if there's something about the American system of health care creating this association. But, when you look across the globe, it's clear that there is something deeper connecting these things together," said Jeffrey Borkan, MD, PhD, chair of family medicine at Brown Medical School and Memorial Hospital of Rhode Island. "A lot more research needs to be done."

There also is great hope that acknowledging the universality of this association will eventually lead to answering what many physicians view as the most important question: What comes first? Is it pain that triggers a worsening of a person's mental state or is it the reverse? Or do the two conditions feed off each other?

"A lot of people that have chronic anxiety and depression vent their pain into joints or backs or necks. A lot of people have physical pain contributing to their anxiety," said Lance Reynoso, MD, a family physician and assistant clinical professor at St. Mary's Hospital in Colorado. "The real question that I want answered is what can we do to figure out what came first and how can we help people with these entities?"

Researchers suggest, however, that pinpointing that "first" may be less critical than identifying the commonality that makes them both worse.

"The more we learn about the common pathways of the neurophysiology of pain and mood and anxiety disorders, which causes which may not be the right question. The overlapping mechanisms may be more important," said Dr. Von Korff.

The World Mental Health Survey will eventually include more than 130,000 people in 26 countries and has already linked several chronic physical conditions to mental status. For instance, a paper published in the March-April General Hospital Psychiatry used survey data to associate asthma with a 50% to 70% increased risk of depression, anxiety and alcohol dependence.