A new report commissioned by Congress is calling into question billions of dollars spent to improve the mental health of military service members and veterans with post traumatic stress disorder (PTSD), the Los Angeles Times reported.

The report, issued by the Institute of Medicine (IOM), found that the government spent $3 billion on PTSD treatments for veterans and $294 million more for service members, but neither the U.S. Department of Defense nor U.S. Department of Veterans Affairs have measured the effectiveness of treatment of PTSD or have kept pace with the growing demand for PTSD treatment.

PTSD is diagnosed by combination of symptoms, including hypervigilence and sleeplessness, and can be treated pharmacologically and psychologically with cognitive behavioral therapies involving multiple sessions with trained counselors.

"Both departments lack a coordinated, consistent, and well-developed evidence-based system of treatment for PTSD and need to do a better job tracking outcomes," Sandro Galea, chair of the IOM committee, and chair of the Department of Epidemiology at Columbia University's Mailman School of Public Health, said in a statement. "Mental health is among the most important factors behind successful re-entry after military service, and we don't know if treatments are working."

Researchers estimate that 5 percent of service members have been diagnosed with PTSD; for veterans who served in Iraq and Afghanistan conflicts, the number rises to 8 percent.

The report recommends that the two agencies enlist a workforce of mental health care providers to meet the growing need for PTSD treatment. While the departments have substantially increased mental health staffing, these increases do not appear to have kept pace with the demand.

"In many respects our findings that neither the DOD nor the VA has a system that documents patients' progress and uses standardized instruments to chart long-term treatment are not surprising," Galeo said. "We are hopeful that the report will provide a blueprint for where we need to get to."

The findings were published on the heels of a scandal at the Department of Veterans Affairs that led to the resignation of VA Secretary Eric Shinseki on May 30. Federal investigators determined that service members were systematically denied timely care in a network of more than 1,700 healthcare facilities that suffers from inefficiency and bureaucracy.