New Jersey medical marijuana is also approved to treat multiple sclerosis, terminal cancer and muscular dystrophy, among other medical diseases. Pictured: New Jersey Gov. Chris Christie responds after being asked about Republican presidential nominee Donald Trump's emotionally charged feud with Khizr and Ghazala Khan, whose son, Capt. Humayun Khan, was killed by a suicide bomber, Tuesday, Aug. 2, 2016, in Trenton, N.J. (Mel Evans, The Associated Press)

Gov. Chris Christie signs bill approving marijuana for PTSD treatment

TRENTON, N.J. — Veterans and others in New Jersey can now legally treat their post-traumatic stress disorder with marijuana.

Republican Gov. Chris Christie signed a measure Wednesday allowing people to use marijuana if their PTSD isn’t treatable with conventional therapy. In a statement sent with the announcement of the bill signing, Christie noted that federal officials estimate up to 20 percent of veterans returning from combat in Iraq and Afghanistan have been diagnosed with PTSD.

But Christie also directed the state’s health commissioner to promulgate additional regulations that provide “clear objective criteria” regarding the drug’s use for PTSD. Christie has said he wants to make sure legalizing medical marijuana doesn’t become a backdoor into legalization for recreational use.

New Jersey is the 18th state to allow medical marijuana to be used to treat PTSD.

New Jersey medical marijuana is also approved to treat multiple sclerosis, terminal cancer and muscular dystrophy, among other diseases. It’s also approved for seizures and glaucoma if those conditions resist conventional treatment.

A growing number of states are weighing whether to legalize marijuana to treat PTSD. But many veterans are increasingly using cannabis even though it remains illegal in most states and is unapproved by the Department of Veterans Affairs because major studies have yet to show it is effective against PTSD.

Federal law requires randomized, controlled trials to prove a drug is effective before VA doctors can recommend it. Such studies are underway, including two funded by Colorado, where the state health board held off on legalizing marijuana for PTSD because of the lack of major studies.