That's because the federal government has a virtual monopoly on growing and cultivating marijuana for scientific research, and getting access to the drug requires three separate levels of approval.
Sisley's fight to get samples for her study — now in its fourth month — illuminates the complex politics of marijuana in the United States.
While 20 states and the District of Columbia have made medical marijuana legal — in Colorado and Washington state the drug is fully legal — it remains among the most tightly controlled substances under federal law. For scientists, that means extra steps to obtain, transport and secure the drug — delays they say can slow down their research by months or even years.
The barriers exist despite the fact that the number of people using marijuana legally for medical reasons is estimated at more than 1 million and growing.
Stalled for decades because of the stigma associated with the drug, lack of funding and legal issues, interest in research into marijuana's potential for treating diseases is heating up. Recent studies and anecdotal stories have provided hope that marijuana, or at least some of the components of the plant, may have diverse applications such as treating cancer, HIV and Alzheimer's disease.
But scientists say they are frustrated that the federal government has not made any efforts to speed the process of research. Over the years, the Drug Enforcement Agency has turned down several petitions to reclassify cannabis, reiterating its position that it has no accepted medical use and remains a dangerous drug. The DEA has said that there is a lack of safety data and that the drug has a high potential for abuse.
Sisley's study got the green light from the Food and Drug Administration in 2011, and for most studies, that would have been enough. But because the study is about marijuana, Sisley faced two additional hurdles.
First, she had to apply to the Department of Health and Human Services to purchase the research-grade samples from the one farm in the United States — housed at the University of Mississippi and managed by the National Institute on Drug Abuse — that is allowed to grow marijuana under federal law. HHS initially denied her application but then approved a revised version March 14 — more than four months after it was submitted.
Now, Sisley must get permission from the DEA to possess and transport the drug.
Dawn Dearden, a spokeswoman for the DEA, said that the agency is supportive of medical research on marijuana but needs to follow regulations under the Controlled Substances Act. "DEA has not denied DEA registration to a HHS-approved marijuana study in the last 20-plus years," she said.
Sisley, who began her work with post-traumatic stress disorder while at the Department of Veterans Affairs and now works at the University of Arizona College of Medicine, says she considers the news from the HHS a "triumph" for marijuana research. But she says the study still has "a potentially long road with the DEA," which "is famous for delays."
"There is a desperate need for this research, but it's impossible to study this drug properly in an atmosphere of prohibition," Sisley said.
Orrin Devinsky, director of the epilepsy center at New York University's Langone Medical Center, said many would-be marijuana researchers are driven to abandon projects after they discover how time-consuming and expensive it can be to obtain the drug.
"There is no rationale for this except for the federal government's outdated 1930s view about marijuana," said Devinsky, who is studying the use of an extract of the plant for the control of seizures.
The cannabis plant was once a staple in American pharmacies, but since the turn of the 20th century, some states began to see it as a poison and introduced restrictions. Research on its medicinal uses came to a virtual standstill.
There are now 156 active researchers who are approved by the DEA to study marijuana — a number that has remained steady in recent years — but scientists say most are government-funded and focus on the ill effects of smoking marijuana rather than potential medicines.
That's poised to radically change. As an increasing number of states have legalized the use of medical marijuana, a bustling industry of start-up drug companies and medical groups focused on finding marijuana-based treatments has emerged. GW Pharmaceuticals, a British company, is studying two different extracts of marijuana that have shown promise for patients with Type 2 diabetes and epilepsy. ISA Scientific, based in Utah, is researching medications for pain and diabetes made from the cannabinoids found in marijuana that could be swallowed in capsule form.
Some of these new-generation researchers are exploring ways to try to speed up their work by bypassing the federal process for obtaining the drug. In Colorado, for instance, academic researchers have asked state officials whether they would allow them to study extracts grown within the state. In Georgia, scientists are seeking legislative action to allow the state's five medical research universities to cultivate marijuana. A bill allowing them to do so recently won the backing of a state House committee.
Much of the debate surrounding marijuana research is focused on its classification by the DEA as a Schedule I drug, the most restrictive of five categories. Schedule I drugs are considered to have a high potential for abuse and no accepted medical use. Other drugs in that group include LSD, heroin and ecstasy.
The American Medical Association said in November that it does not support state medical marijuana efforts and still considers the drug dangerous. But it also called on the government to encourage more clinical research — by reconsidering its classification as a Schedule I drug. A lower-level classification would allow researchers to obtain marijuana more easily.
But the fact that the Obama administration in recent months has taken action to loosen restrictions on marijuana in other regards has raised hopes that it will take similar action that will help scientists. The Justice Department said last year that it would not challenge state laws legalizing marijuana, and in February, the Treasury announced new guidelines meant to make it easier for cannabis businesses to open bank accounts in states where the drug is legal.
Kevin Sabet, a former White House senior adviser for drug policy who has been dubbed the No. 1 legalization enemy by Rolling Stone magazine, said he supports efforts to break down barriers for researchers. But he proposed that this could be done more efficiently without rescheduling the drug — which remains highly controversial and would have implications for the criminal justice system.
Sabet signed a letter sent this month to senior administration officials by a coalition of people working in drug prevention and other related causes. The letter suggested that the DEA could instruct field offices to process applications without delay after FDA approval and could relax storage requirements for the components of marijuana used in the context of an investigational new drug.
In the brave new world of medical marijuana, family doctors, psychiatrists and other community practitioners are the gatekeepers and must determine whether a patient truly needs the drug. But in many cases, doctors are prescribing the drug for their patients against the recommendations of medical societies and with only limited research to back up what they are doing.
"The whole process is wrong," said Andrew Weil, the American doctor and author who conducted the first double-blind clinical trials of marijuana in 1968.
"There is a great deal of evidence both clinical and anecdotal of its therapeutic effects, but the research has been set way back by government polices," Weil added.
"We are at the point where we are really just learning about this, and for doctors that means a lot of experimentation," said Bonnie Goldstein, a pediatrician who is medical director of the Ghost Group, which manages WeedMaps.com, a searchable directory of doctors and dispensaries.
In most states, for instance, marijuana is approved for pain and prescribed for those with arthritis. But a study published in the journal of the American College of Rheumatology this month found that the effectiveness and safety of marijuana to treat conditions such as arthritis are not supported by medical evidence.
Another condition for which medical marijuana is widely prescribed is PTSD. Yet the American Psychiatric Association discourages doctors from using it to treat psychiatric disorders. In a statement released in November, the APA said: "There is no current scientific evidence that marijuana is in any way beneficial for the treatment of any psychiatric disorder."
Sisley said she has been working with marijuana for several years to treat soldiers returning from Afghanistan and Iraq who have flashbacks, insomnia and anxiety,but she has had questions about dosages that haven't been answered. Is one gram a day optimal? Or two? Is it better to smoke the marijuana or use a vaporizer, which heats ground marijuana leaves to produce a gas?
Sisley — who is working on the PTSD study with Rick Doblin, a psychologist and executive director of the Multidisciplinary Association for Psychedelic Studies — says she believes the next big political fight over marijuana may come from studies such as hers. If research shows that marijuana is an effective medical treatment, it could force the federal government's hand on reclassifying the drug.
