Montana is a hotbed of contradiction, especially when it comes to medical marijuana. Voters overwhelmingly approved medical marijuana in 2004, but in 2011 the state legislature voted to dramatically restrict access to medical marijuana.

Now, Montana PBS has produced an exemplary documentary, Clearing the Smoke: The Science of Cannabis, focusing on the medical uses of marijuana, with interviews with patients, doctors, scientists and medical marijuana critics.

A partial transcript of the program is on the PBS website.

MEDICAL MARIJUANA USER: I have taken pretty much every anti-epileptic on the market, and some with a little bit more success than others. PBS Reporter ANNA RAU: None of them stopped her seizures, and, by her early 20s, the epilepsy had also spawned depression, anxiety and insomnia. She had to withdraw from college just a few credits short of a fine arts degree. Unable to hold a job, she was bed-bound for years while the epilepsy ruled her life. MEDICAL MARIJUANA USER: It’s not a life, to live like that. ANNA RAU: Then she remembered reading stories about the potential of cannabis to treat epileptic seizures, and she desperately wanted to try it, but her home state doesn’t have a medical marijuana law. MEDICAL MARIJUANA USER: So, I did what I could do. I moved to a state where I could treat it myself.

In Colorado, teenager Chaz Moore, known as Bill Smith to many, has been using medical marijuana to control seizures for almost a year. Like the patient Rau interviewed, he too tried many other medicines, none of which were effective.

Rau also interviews Dr. Eric Voth, chairman of the Institute on Global Drug Policy, who complains that drugs should be approved by the FDA and not approved by individual states through votes of the citizenry or legislature, which are not equipped to decide what medicines should be legal or what they should be used for.

He also argues that the various cannabinoids in marijuana need to be separated from one another so that patients only get the medicine they need and not any of the other parts of the drugs. The recent sequencing of a cannabis genome may be an early step in that direction.

DR. ERIC VOTH: If we’re delivering THC, which is the major active ingredient, shouldn’t we be delivering that alone or other cannabinoids alone? But, in fact, what we’re doing is we’re delivering not only one, but 66 cannabinoids. On top of that, were delivering hundreds of contaminants. ANNA RAU: This epilepsy patient says she’s willing to take the risk, because something in that cornucopia of substances has changed her life. How did that impact your seizures? MEDICAL MARIJUANA USER: They started slowing down. I had to build it up in my system. And it wasn’t until I started ingesting it that they really stopped completely. DR. ERIC VOTH: I’m very suspicious about it because for someone to have been on 14 medications and not solve her problem, and then have this miraculous benefit from one medicine, I just find that suspect. ANNA RAU: But the potential of marijuana to mitigate epileptic seizures has been recognized by the U.S. Institute of Medicine. The institute has released two reports on the therapeutic potential of cannabis. The first report, from 1982, found “substantial evidence from animal studies to indicate that cannabinoids are effective in blocking seizures.” Scientists who wrote the 1999 report also found marijuana had anti-seizure effects, but doubted it could be developed into a pharmaceutical-grade epilepsy drug.

Rau also talked to doctors and scientists about the tumor and cancer fighting properties of cannabis. Many individual patients and doctors have told anecdotal stories about marijuana being used to cure cancer, but she also interviews a professor who talks about cannabis-based drugs being shown to eliminate cancer in mice.

ANNA RAU: Dr. Prakash Nagarkatti is a professor of pathology and microbiology at the University of South Carolina. He’s one of many scientists in a race to unlock the mysteries of the receptors by using newly created synthetic drugs, instead of tightly restricted whole cannabis. These synthetics have made research much easier and potentially lucrative. The U.S. patent database shows numerous large pharmaceutical companies have filed recent patents, claiming their cannabinoid receptor drug has the potential to treat almost everything: multiple sclerosis, Alzheimer’s, Parkinson’s, rheumatoid arthritis, Tourette’s, epilepsy, heart disease, obesity, various mental illnesses and the Holy Grail of medicine, a cancer cure. Dr. Nagarkatti and his team of researchers were one of the first labs to prove a cannabinoid key can seek out a cancerous cell in the immune system, unlock the receptor, and direct the cancer cell to self-destruct. DR. PRAKASH NAGARKATTI: So, basically, telling the cells basically to commit suicide. ANNA RAU: Dr. Nagarkatti’s experimental drug was able to eradicate almost 100 percent of the cancer in test tubes. And when they moved on to live mice: DR. PRAKASH NAGARKATTI: To our surprise, we found that almost 25 to 30 percent of the mice completely rejected the tumor. They were completely cured. ANNA RAU: Tumors in the rest of the mice shrank significantly. The results have been so promising that Dr. Nagarkatti is already beginning clinical trials with leukemia patients. Dr. Voth believes researchers like Nagarkatti are headed in the right direction. DR. ERIC VOTH: Let’s keep it in the corridors of science. Let’s keep it in the FDA. Let’s deliver what’s really medicine. That is the individual cannabinoids.

Watch the full episode. See more MontanaPBS Presents.