ST. LOUIS – Chronic use of pain-relieving medication can increase in the risk of developing major depression, according to a new veterans study. The study, led by researchers from Saint Louis University and published recently in the Journal of General Internal Medicine, is based on analysis of medical record data from about 50,000 veterans who had no history of opioid use or depression and were subsequently prescribed opioid pain killers.¹ Researchers found that patients who started and remained on opioids for 180 days or longer were at a 53% greater risk of developing a new episode of depression. Veterans using opioids for 90-180 days were at a 25% increased risk, compared with patients who never took opioids for longer than 1-89 days. “These findings suggest that the longer one is exposed to opioid analgesics, the greater is their risk of developing depression,” said principal investigator Jeffrey Scherrer, PhD. “Opioids have long been known to allay pain and suffering, but reports of adverse effects are abundant and continue to emerge.” Although there is no clear evidence about how opioids could contribute to the development of depression in a patient, Scherrer suggested there could be several factors that lead to that outcome. Among those, he said, are opioid-induced resetting of the brain’s “reward pathway” to a higher level, which means the chronic use of narcotic pain-killers can elevate the threshold by which humans experience pleasure from natural rewards such as a food or sexual activity. Other factors might include body aches months and years after the use of opioids has stopped, as well as side effects such as adrenal, testosterone and vitamin D deficiencies and glucose dysregulation, Scherrer added. The study, which was funded by the VA HSR&D also suggested 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 lower risk for depression,” Scherrer noted. ¹Scherrer JF, Svrakic DM, Freedland KE, Chrusciel T, Balasubramanian S, Bucholz KK, Lawler EV, Lustman PJ. Prescription opioid analgesics increase the risk of depression. J Gen Intern Med. 2014 Mar;29(3):491-9. doi: 10.1007/s11606-013-2648-1. Epub 2013 Oct 29. PubMed PMID: 24165926; PubMed Central PMCID: PMC3930792.  

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