Legislation signed this week by Governor Jan Brewer will once again allow medical marijuana onto university campuses - at least in a limited fashion. Arizona Public Radio's Howard Fischer reports.

The law approved by voters in 2010 allows those with a doctor's recommendation to obtain up to 2.5 ounces of marijuana every two weeks. But last year lawmakers altered that to say no marijuana on college and university campuses, even for patients. One bit of fallout is it brought to a halt efforts by University of Arizona physician Sue Sisley to do on-campus research.

Sisley said this new law removes that impediment. "We're going to be looking at combat veterans who have treatment-resistent PTSD," Sisley said. "So, that means they failed medication and psychotherapy. And we're going to be examining five different dosages of both smoke and vaporized marijuana."

Her own research aside, Sisley said the legislation points-up the value of the state's university system. "I think that's the real purpose of a public university," Sisley said, "is to be able to examine subjects that are hard or controversial or complex in an environment that isn't plagued by politics."

Sisley already has approval from one federal agency as well as the go-ahead from the university but still needs sign-off from the Drug Enforcement Administration.