The Department of Veterans Affairs (VA) is under pressure to ease restrictions on veterans' access to medical marijuana to help treat pain and other ailments.

Veterans advocacy groups want to know if marijuana can treat chronic pain, as well as help address widespread suicides among veteran communities.

While 33 states and the District of Columbia have legalized marijuana for medicinal purposes, veterans are finding themselves fighting stigma and roadblocks from the federal government's drug laws.

Under official federal policy, VA health care providers may not recommend marijuana or assist veterans in obtaining it. The VA also won't reimburse veterans who pay for marijuana out-of-pocket.

Marijuana is a Schedule I drug, meaning it is in the same category as drugs like heroin and LSD. According to the federal government, it has a high potential for abuse and no accepted medical value. Until that classification changes, the VA has said its hands are tied.

"[The House Veterans' Affairs Committee] can make strong proposals for us to move forward with recommendations of filling out forms and such but, in the end, we need to go back to the [Drug Enforcement Agency] DEA and [Justice Department] for their opinion," Larry Mole, chief consultant for population health at the VA, said during a House hearing in the spring.

That opposition is frustrating members of Congress and some leading advocacy groups, and there is a growing bipartisan push to ease the prescribing ban, as well as force the agency to conduct research into the drug's efficacy.

Both the American Legion, the country's largest veterans organization, and Veterans of Foreign Wars support research into the medicinal uses of cannabis. They have made the issue a top legislative priority.

"If there's a viable medical treatment available to civilians, it's not just inappropriate, it's patently unjust that veterans don't have access to it," said Lindsay Rodman, an executive vice president at the Iraq and Afghanistan Veterans of America, which represents the country's youngest veterans.

Despite an existing VA directive, veterans risk having a negative mark in their permanent records if they are flagged using legal medical marijuana.

Former VA Secretary David Shulkin said it would be safe for veterans to talk about marijuana with their providers. But veterans groups argue there's still a stigma, and some vets are reluctant to bring up the issue.

Pending legislation in the House Veterans' Affairs Committee could help.

One bill, sponsored by Reps. Lou Correa (D-Calif.) and Clay Higgins (R-La.), would require the VA to conduct research on the effects of medicinal cannabis on veterans diagnosed with chronic pain and PTSD.

Another bill from Rep. Greg Steube (R-Fla.) would ensure that the VA secretary won't deny a veteran benefits because the veteran participates in a state-approved marijuana program.

Steube said veterans are getting caught between the states and the federal government, and he wants to change that.

"Veterans who were taking advantage of this state-approved program were having challenges with the VA and their benefits with the VA. There was a lot of confusion," including cases where veterans were being told they would lose benefits, Steube told The Hill.

"If we have veterans who have gone through the process ... they shouldn't be denied that health care they've earned just because they were taking advantage of state-approved medicinal marijuana programs," he said.

Another bipartisan bill from Rep. Earl Blumenauer (D-Ore.) would allow VA doctors to give recommendations and opinions to veterans regarding participation in state marijuana programs.

Blumenauer withdrew a similar amendment from the annual House spending bill in June, but his legislation remains active in the committee.

VA leadership strongly opposes all the bills, and advocates admit that even if the legislation passes the House, Senate Republicans will be reluctant to buck the administration.

"We are realistic it will be a much more difficult problem to pass it in the Senate than the House," Rodman said.

Other marijuana legislation that's not specific to veterans could still help veterans gain access. For example, Steube also introduced a bill to reschedule marijuana from a Schedule I controlled substance to a Schedule III controlled substance, to make it easier to research.

VA officials have said that the department supports medical marijuana research, and the agency is conducting some trials.

But the studies are small-scale, and lawmakers want the agency to go further. They argue the VA has the authority to allow rigorous clinical trials but is using bureaucratic red tape as an excuse.

"We authorized VA last year to do the studies. They didn't do it," Rep. Phil Roe (R-Tenn.) said during a recent hearing. "We need to make sure that they have to study [medical marijuana]. I just don't think we as politicians should be telling scientists how to design the studies."

The federal government has put significant restrictions on cannabis research. Scientists need permission from a host of federal agencies to start the research, including the Food and Drug Administration, the DEA and the National Institute on Drug Abuse.

Even then, there is only one facility in the country that is allowed to grow marijuana and distribute it for research purposes, and there have been concerns raised that the marijuana grown at the facility is poor quality.

The VA has also in the past declined to participate in FDA-approved private sector research on medical marijuana and veterans' post-traumatic stress disorder, and has blocked researchers from having access to VA hospitals and veterans who might benefit from the research.

But advocates insist they'll keep up pressure on the VA.

Veterans groups say it doesn't matter what the research concludes. They say they just want the VA to be able to conduct it, and they want veterans to be able to talk to their providers about whether they should be using marijuana.