An effort to align the medications carried in both Defense and Veterans Affairs department pharmacies has exposed differences between the departments' approaches to monitoring prescriptions and treating post-traumatic stress, a new government report has found.

A Government Accountability Office investigation into DoD and VA prescribing practices for post-traumatic stress disorder and mild brain injury found that the VA closely monitors its physicians' practices in prescribing medications for PTSD, especially drug classes like benzodiazepines and anti-psychotics that are discouraged for use in PTSD patients.

But the Defense Department largely relies on the military services to review medication-prescribing practices of their physicians and, while DoD monitors prescriptions, it does not track medication use in relation to PTSD diagnoses.

The Army issued a policy in 2012 requiring military hospitals to review their prescribing practices for atypical anti-psychotics, and according to the service, the percentage prescribed dropped by nearly half, from 19 percent in fiscal 2010 to 10 percent in fiscal 2014.

The policy expired in 2014.

Army doctors interviewed by GAO at one facility said they continue to monitor these prescriptions because they saw higher-than-expected prescribing rates for these drugs at their facility. Doctors at other Army facilities said, however, that they no longer monitored these prescriptions because they felt the awareness effort had been effective.

GAO Health Care Director Debra Draper said the military should improve its monitoring standards and align them with the VA's system to ensure that doctors are following recommended treatment guidelines for PTSD and concussions.

"Without such monitoring, the Army may be unable to identify and address practices that are inconsistent," Draper wrote.

The fiscal 2016 National Defense Authorization Act required the DoD and VA to carry the same medications to treat mental and sleep disorders and pain.

Lawmakers had raised concerns that veterans were suffering because they were unable to get the medicines they had been prescribed by DoD doctors after leaving the service.

GAO found that VA largely has processes in place to ensure that transitioning veterans could get their medications at a VA facility, such as specialty request forms and a policy issued in 2015 instructing doctors not to discontinue patients' DoD-prescribed mental health medications due to formulary differences.

A GAO survey of 729 veterans found that 24 of them, or 3 percent, had their medications changed at VA for "non-clinical" reasons.

While VA officials told GAO that cost is a factor in determining which medicine to include in its formulary, it also does not carry some medications out of safety concerns or differences in treatment approaches.

For example, VA officials said they did not carry the pain medication piroxicam because it believes its formulary offers safer alternatives. It carries only two sleep medications, VA told GAO, because administrators have concerns about the appropriateness of prescribing some sleep medications to treat insomnia instead of treating the underlying condition for the sleeplessness.

GAO recommended that the DoD and the Army — which it examined for the report because it had the largest number of troops serving in Iraq and Afghanistan — implement processes to monitor prescriptions for PTSD.

Draper also recommended VA clarify which types of medications are covered by the Veterans Health Administration 2015 policy on medical continuation.

Both departments concurred with the GAO recommendations in written responses to the report.

Assistant Secretary of Defense for Health Affairs Dr. Jonathan Woodson said the military services will continue focusing on education and training their providers, and the Defense Health Agency will monitor pharmacological prescribing practices "when appropriate."

VHA said it plans to publish a list of the medications covered in the 2015 policy.