COLORADO SPRINGS, Colo. — Some American parents who for years have used cannabis to treat severe forms of epilepsy in their children are feeling more cautious than celebratory as U.S. regulators near a decision on whether to approve the first drug derived from the marijuana plant.

The U.S. Food and Drug Administration is expected to issue a decision by the end of the month on the drug Epidiolex, made by GW Pharmaceuticals.

It’s a purified form of cannabidiol — a component of cannabis that doesn’t get users high — to treat Dravet and Lennox-Gastaut syndromes in kids.

Cannabidiol’s effect on a variety of health conditions is frequently touted, but there is still little evidence to back up advocates’ personal experiences.

Meagan Patrick is among the parents using CBD to treat symptoms in their children.

She moved from Maine to Colorado in 2014 so she could legally get CBD for her now-5-year-old daughter, Addelyn, who was born with a brain malformation that causes seizures.

“My child was dying, and we needed to do something,” Patrick said.

Advocates like Patrick became particularly concerned when GW Pharmaceuticals’ U.S. commercial business, Greenwich Biosciences, began quietly lobbying to change states’ legal definition of marijuana, beginning in 2017 with proposals in Nebraska and South Dakota.

Neither Nebraska nor South Dakota allows medical use of marijuana, and activists accused the company of trying to shut down future access to products containing cannabidiol but lacking FDA approval.