Chronic, Noncancer Pain Boosts Suicide Risk

Certain types of noncancer pain conditions are associated with an increased risk for suicide, a new study suggests.

A study conducted by investigators at the University of Michigan in Ann Arbor showed that psychogenic pain, back pain, and migraine, but not arthritis or neuropathy, were associated with an increased risk for suicide.

Although some of this risk appears to be due to co-occurring mental health problems, there may be something about the experience of pain that also contributes directly to suicide risk, lead author Mark A. Ilgen, PhD, told Medscape Medical News.

"Treatment providers, particularly those who work in pain treatment settings, should be aware of these risks and consider mental health and suicide risk assessments in their patients," Dr. Ilgen said.

Previous research suggests that individuals with pain may be at increased risk for suicidal thoughts and behaviors, but it is likely that "not all pain is created equal" in terms of its association with suicide, and that the association between pain and suicide could vary, depending on the type of pain patients experience, Dr. Ilgen said.

The study was published online in JAMA Psychiatry.

Arthritis Most Common Dx

In the current study, the investigators sought to understand the degree to which specific pain conditions related to suicide risk. The investigators also wanted to understand whether pain remained an important predictor of suicide, even after controlling for other mental health conditions that are associated with both pain and suicide risk.

The team looked at treatment records of all patients (n = 4,863,036) who were seen in the Veterans Health Administration system in fiscal year 2005 and who were alive at the start of fiscal year 2006.

They then examined the association between baseline clinical diagnoses of the following pain-related conditions: arthritis, back pain, migraine, neuropathy, headache or tension headache, fibromyalgia, and psychogenic pain, as well as the extent to which each of these conditions predicted risk for suicide in fiscal years 2006 to 2008.

Arthritis was the most common diagnosis, occurring in 2,076,514 patients (42.7%), followed by back pain, in 1,111,187 (22.8%). Psychogenic pain was the least frequent diagnosis, occurring 18,145 patients (0.4%). Suicide occurred in 4823 (0.01%) in the subsequent fiscal years.

After controlling for demographic and other factors, including age, sex, and Charlson score, the researchers found that except for arthritis and neuropathy, each pain condition was associated with an elevated risk for suicide.

Psychogenic pain was associated with the greatest risk for suicide death (hazard ratio [HR], 2.61; 95% confidence interval [CI], 1.82 - 3.74).

Back pain was associated with a 33% increased risk for suicide death (HR, 1.33; 95% CI, 1.22 - 1.45), migraine with a 68% increased risk (HR, 1.68; 95% CI, 1.28 - 2.20), headache or tension headache with a 38% increased risk (HR, 1.38; 95% CI, 1.17 - 1.64), and fibromyalgia with a 45% increased risk (HR, 1.45; 95% CI, 1.16 - 1.81).

When these analyses were further controlled for concomitant psychiatric conditions, these associations between pain conditions and suicide death were reduced.

However, significant associations remained for back pain (HR, 1.13; 95% CI, 1.03 - 1.24), migraine (HR, 1.34; 95% CI 1.02 - 1.77), and psychogenic pain (HR, 1.58; 95% CI, 1.11 - 2.26).

Controversial Diagnosis

"Psychogenic pain is listed within the ICD-9 [International Classification of Diseases, Ninth Revision] coding system and characterizes pain that is caused by psychological instead of purely physical factors," Dr. Ilgen explained.

"This is a diagnosis that is used relatively infrequently within the VA, and there is considerable disagreement among pain and mental health professionals about the validity and utility of this diagnosis," he said.

Because of the type of data that were analyzed in this study, it is impossible to tell what treatment providers were thinking when they used the diagnosis of psychogenic pain, Dr. Ilgen added.

"Still, this diagnosis had the strongest association with suicide of any of the pain disorders that we examined. It is my guess that a diagnosis of psychogenic pain is given to patients with pain that is poorly understood and that may be particularly difficult to treat. Also, there is the possibility that patients with this diagnosis are particularly frustrated with their care and hopeless about the resolution of their pain condition. I do not interpret our findings to indicate that 'psychogenic pain,' as it is defined in the ICD-9, is directly causing suicide, rather, that there is something about being diagnosed with this condition that is associated with a particularly poor prognosis."

Need for Screening and Treatment

Commenting on this study for Medscape Medical News, Colonel (retired) Elspeth Cameron Ritchie, MD, chief medical officer for Washington, DC, Department of Mental Health and an expert on suicide in the military and veterans population, called it important, although not a surprise.

"It's not a revelation because anecdotally, we have known that pain is a risk factor for depression and for suicide. But it is looking at a very large population, and this adds to its importance," she said.

Dr. Ritchie, who retired from the army two years ago, said she saw this firsthand.

"Pain was a major risk factor. Many service members, after 12 or 20 years of service, have a lot of aches and pains. So in the military, pain is a risk factor."

She added that for her, the "take-home message" is that clinicians should be evaluating suicide risk in all patients with pain.

"The standard questions for evaluating risk for suicide are, 'Have you given away your possessions?' and 'Have you made a will?,' but it's not a standardized question in the psychiatric setting to ask about pain, and it absolutely should be."

Also, asking about pain is not enough. Clinicians should make sure that patients with pain are getting appropriate treatment, she added.

The study was sponsored by the Veterans Health Administration. Dr. Ilgen and Dr. Ritchie report no relevant financial relationships.

JAMA Psychiatry. Published online May 22, 2013. Abstract

Fran Lowry • Medscape Medical News © 2013 WebMD, LLC

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