Chronic use of pain-relieving medication appears linked to a higher risk of developing major depression, according to a study.
Jeffrey Scherrer, PhD, associate professor of family and community medicine at Saint Louis University, and colleagues analyzed medical record data of about 50,000 veterans who had no history of opioid use or depression and who subsequently were prescribed opioid analgesics.
According to the findings, published Oct. 31 on the website of the Journal of General Internal Medicine, patients who started and remained on opioids for 180 days or longer were at a 53% increased risk of developing a new episode of depression, and those using opioids for 90-180 days were at a 25% increased risk compared with patients who never took opioids for longer than 89 days.
These findings suggest that the longer one is exposed to opioid analgesics, the greater is their risk of developing depression, Scherrer said in a news release. Opioids have long been known to allay pain and suffering, but reports of adverse effects are abundant and continue to emerge.
Scherrer said despite a lack of clear evidence about the mechanisms by which opioids may contribute to the development of depression in a patient, several factors may be in effect. Some of these include opioid-induced resetting of the brains reward pathway to a higher level, which means the chronic use of narcotic pain relievers can elevate the threshold for a persons ability to experience pleasure from natural rewards such as a food or sexual activity.
Other factors may include body aches months and years after the use of opioids has stopped, side effects such as adrenal, testosterone and vitamin D deficiencies, and glucose dysregulation.
The study also suggests that the higher the dose of opioid analgesics, the greater the risk of depression. Preliminary evidence suggests that if you can keep your daily dose low, you may be at a lower risk for depression, Scherrer said in the news release.
Scherrer said recent studies indicate the use of prescription opioid analgesics has quintupled recently, and more than 200 million prescriptions were issued to patients in 2009 in the U.S. Even though the risk is not huge, there is enough exposure that we may have a public health problem, he said.
Study abstract: http://link.springer.com/article/10.1007/s11606-013-2648-1