A study published in Oxford Academic Pain Medicine on September 7, 2018, showed that U.S. military veterans of operations Enduring Freedom, Iraqi Freedom, and New Dawn used less opioid medication if they also received chiropractic care at a VA facility.

This study specifically looked at veterans who were involved in operations Iraqi Enduring Freedom, Iraqi Freedom, and New Dawn. The veterans in this study made at least one visit to a Veterans Affairs (VA) chiropractic clinic between the years 2004 and 2014. For the purposes of this study, opioid usage was described as a prescription given to a veteran somewhere between 90 days before a chiropractic VA visit, as well as up to 90 days after a chiropractic VA clinic visit.

The study found that veterans were more likely to be prescribed opioids if they had moderate to severe pain, or  if they had PTSD or depression. The study did show that those veterans who received chiropractic care had a significantly lower usage of opiates after receiving chiropractic care as compared to those veterans who did not receive any chiropractic care at all.

In the study conclusion, the authors state, "Nearly one-third of (Operations Enduring Freedom, Iraqi Freedom, and New Dawn) veterans receiving VA chiropractic services also received an opioid prescription, yet the frequency of opioid prescriptions was lower after the index chiropractic visit than before. Further study is warranted to assess the relationship between opioid use and chiropractic care."

In explaining the results the authors wrote, "The percentage of veterans receiving opioid prescriptions was lower in each of the three 30-day time frames assessed after the index chiropractic visit than before. Our work did not attempt to assess causation or otherwise explain this observation. Veterans may have been referred to chiropractic care as part of an opioid taper plan, or those who agreed to chiropractic care may have been inherently less likely to seek opioid prescriptions. However, it is also possible that the delivery of chiropractic care may have been a substitute for opioid use in our sample, which raises interesting research, policy, and practice considerations as the VA continues to expand chiropractic services. This is particularly relevant in light of other work that has shown a negative correlation between chiropractic use and opioid use in private sector populations."

Another study published in October 2018 showed that the duration of prescription opioid drugs is a risk factor for non-medical usage of prescription opioids among veterans receiving medical care. Therefore, it makes sense that anything that reduces the use of opioids by veterans reduces the inherent risks of opioid usage both medically and non-medically. Chiropractic has been shown to be a key factor in reducing the usage of opioids.