SAN DIEGO — When chronic pain and depression coexist, treat the patient under the assumption that the pain is causing the depression, not the reverse, Rollin M. Gallagher, M.D., said at a psychopharmacology congress sponsored by the Neuroscience Education Institute.
Studies have shown that pain precedes depression in a majority of patients who have both, he said. That said, depression or an anxiety disorder can intensify a patient's perception of pain.
Physicians need to ensure that patients with pain and depression get referred to pain specialists or psychiatrists early, said Dr. Gallagher, director of pain medicine at Philadelphia Veterans Affairs Medical Center and professor of psychiatry and anesthesiology at the University of Pennsylvania, Philadelphia.
Treatment that improves both physical and affective symptoms provides the best chance of remission of depression.
Keep an eye out for pain in patients treated for depression, he added. Someone with a history of recurrent depression is prone to relapse soon after the onset of pain. “You need to treat the pain right away,” Dr. Gallagher said.
Unexplained somatic symptoms, including pain, were the chief complaints among 69% of 1,146 patients who met the criteria for major depression, one international study found (N. Engl. J. Med. 1999;341:1329–35).
“Probably all of these patients have disorders of the sensory nervous system that you don't find on the typical physical exam but that you could see if you did imaging studies of the brain,” he said.
It's estimated that 30%–60% of depressed patients have pain, according to both clinical and population-based studies. Conversely, about two-thirds of patients with chronic pain conditions have a lifetime history of major depressive disorder.
Physical symptoms and depression are linked across cultures, which suggests that physical symptoms are as much a core part of depressive disorder as sleeplessness, depressed mood, and apathy. Pain associated with depression is more common in women than in men.
A study comparing 248 depressed patients in primary care with 794 nondepressed patients found that depressed patients were significantly more likely to have fatigue, sleep disturbance, more than three complaints, and a variety of pain complaints. Nonspecific musculoskeletal complaints and back pain especially are tip-offs that a patient may be depressed.
Psychiatrists and family physicians usually excel in looking for depression in patients with physical complaints, but other specialists often overlook the depression, Dr. Gallagher said.
He suggested routinely asking patients with physical complaints a couple of questions that are helpful to screen for depression: “Are you depressed most days, or have you been depressed most of the time in the last 2 weeks? Are you interested in doing the things you normally do?” While not specific for depression, these questions are quite sensitive in identifying patients who deserve further work-up for possible depression, studies have shown.
Dr. Gallagher described a 75-year-old woman whose grown children were considering placing her in a nursing home because she seemed confused and depressed, and would not leave her house. In an evaluation, Dr. Gallagher found no new disease, but she did have osteoarthritis in her knees, hip, and spine; spinal stenosis associated with corrective surgery for scoliosis; and brachial plexopathy following prior mastectomy and radiation for breast cancer. She was in severe pain, was quite depressed, and was wasting away.
He hospitalized her, treated the pain with a fentanyl patch and IV morphine, started an antidepressant, and 4 days later transferred her to a step-down clinic where she started physical therapy. She went home 10 days later with pain medications and an antidepressant, and has lived independently for the past 5 years.