Colorado’s Board of Health on Wednesday approved up to $8.4 million of grants to pay for eight studies on medical marijuana, part of the largest-ever state-funded effort to study the medical efficacy of cannabis.

The studies will look at whether marijuana can be used to treat childhood epilepsy, post-traumatic stress disorder, Parkinson’s disease, inflammatory bowel disease, pediatric brain tumors and spine pain. University researchers will conduct all of the studies, meaning the results will provide some of the best — and most respected — evidence to date on whether marijuana is a useful medicine.

“This is new and uncharted territory,” Dr. Larry Wolk, executive director of the Colorado health department, said prior to the board’s unanimous vote to approve the funding.

Last year, the state legislature authorized the Colorado health department to spend $9 million on medical marijuana research, meaning there remains as much as $1 million that will be used to expand the already-approved studies or fund additional research. An additional $1 million will be used for the program’s administrative expenses.

The money comes from the registration fees that patients pay to be on the state’s medical marijuana registry. But the funding mechanism has prompted a lawsuit from a group of medical marijuana advocates that could threaten the grant program.

The Patient and Caregiver Rights Litigation Project is asking a judge in Denver to block the program’s implementation, saying that Colorado’s medical marijuana amendment requires patient fees be used only for administrative purposes. Spending the money on research is an unconstitutional use of the funds, the lawsuit contends.

“It’s not going to happen,” Kathleen Chippi, one of the lawsuit’s plaintiffs, told the Board of Health on Wednesday about the grant program. “You don’t have the legal right.”

Chippi said her group would prefer the state use private dollars or money from elsewhere in the state budget to fund the studies.

Other medical marijuana supporters, though, pleaded with the Board of Health to approve the grants. Wendy Turner, whose son uses cannabis to treat his Crohn’s disease, broke into tears while describing her son’s condition. She said he was in a wheelchair when the family moved this year to Colorado from Illinois for access to medical marijuana. This summer, with his disease in remission, he was able to climb mountains, Turner said.

“This research is important because there are so many other kids out there like this,” she said.

Veterans’ supporters also backed the grants. Chris Latona, a veteran of the war in Afghanistan, said, if marijuana is proven an effective treatment for post-traumatic stress disorder, it could stem an epidemic of veterans’ suicides.

“We need to use every tool available at this point to save these young men and women’s lives,” he said.

Colorado’s program builds on the work of California’s Center for Medicinal Cannabis Research, which spent $8.7 million over 12 years on medical marijuana studies. Wolk said Colorado’s program hopes to supplement existing research, not reinvent it.

“This is not to be the be-all and end-all of research on these clinical conditions,” he said. “This is to try to provide meaningful contributions to the body of research that already exists.”

Tom McGhee: 303-954-1671, tmcghee@denverpost.com or twitter.com/dpmcghee