Enlarge By Craig Fritz for USA TODAY Robert Jones, a state-licensed medical marijuana user for his cancer, worries that he will lose his federal subsidy for HUD housing. Jones says marijuana helps him deal with the nausea that he gets from his chemotherapy. Marijuana helps Robert Jones deal with nausea and anxiety that come with chemotherapy. He has been dealing with a lot of stress ever since he was told that his rent subsidy would end because marijuana is illegal under federal law. The drug, which was recommended by his doctor, is legal in New Mexico. "My eyes are fogging up as they do when I'm stressed," says Jones, 70. "I'm getting anxiety. I don't know what's going to happen next." CLASH: State, federal laws collide MORE: Medical pot use, job rules can conflict Jones is among patients with cancer, chronic pain and other maladies who say smoking marijuana helps their condition. Many, though, are trapped between state laws that allow medical pot smoking and federal laws that do not. Sixteen states have approved medical marijuana. Attorney General Eric Holder told U.S. attorneys in 2009 to refrain from prosecuting "individuals whose actions are in clear and unambiguous compliance with existing state laws providing for the medical use of marijuana." That applies only to the Justice Department. "There still are people in the Obama administration who take a much more hostile approach," says Keith Stroup, legal counsel for the National Organization for the Reform of Marijuana Laws. Democratic Rep. Barney Frank of Massachusetts, chairman of the banking committee, and 14 other Democratic and Republican members of Congress have asked Treasury Secretary Tim Geithner to adopt a policy for federally insured national banks similar to the Justice Department's. Like Treasury, other federal departments enforce the law against marijuana. Travelers with medical pot are arrested. People who lose their jobs after testing positive for marijuana can be denied unemployment benefits. People who live where the Border Patrol operates have their marijuana confiscated. The Department of Veterans Affairs has largely resolved the conflict at its hospitals and pain clinics. Until last summer, the VA would not give pain medication to patients seeking treatment at its pain clinics who tested positive for marijuana. Now, veterans in states where marijuana is approved for medical use can submit documentation showing they have legal access to pot, which means a patient who tests positive will not be denied treatment. Some patients with chronic pain use marijuana to magnify the effect of painkillers, which allows them to use less of those drugs and reduce the risks of addiction and digestive problems, says Michael Krawitz, executive director of Veterans for Medical Cannabis Access. Pot also helps vets with nerve pain and phantom limb pain after amputation, conditions that are hard to treat with traditional drugs, he says. Jones, an outspoken advocate of medical marijuana who rents a house for $400 a month, was told by public housing officials last month that they planned to take away his $156 monthly subsidy because he is engaged in criminal activity by smoking marijuana. Jones, who has anal cancer, says a doctor recommended in 2007 that he use marijuana for the nausea caused by chemotherapy, "which was quite severe." Now, "whenever I have to eat, I have to smoke a bit," he says. "I'm trying to eat it and not smoke it because I have lung problems." He also takes it for depression, and it has helped him stop taking other pain and anxiety medications, he says. Mandy Griego, New Mexico administrator for the Department of Housing and Urban Development, cites national policy saying all users of illegal drugs must be treated the same. Jones is abiding by New Mexico's medical-use law, Stroup says. "What's he to do, live out in the street?" Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more