RELIEF, NOT RECREATION. Epidiolex contains cannabidiol (CBD), one of the two main compounds in cannabis. Unlike the other compound, delta-9 tetrahydrocannabinol (THC), CBD doesn't produce a "high," so users of Epidiolex won't get the same buzz from using the medication that a recreational user expects to get from smoking THC-containing marijuana.
Still, before GW Pharmaceuticals can sell Epidiolex, the U.S. Drug Enforcement Agency (DEA) needs to recategorize CBD, which means rethinking marijuana, too. Marijuana is currently a Schedule I drug, meaning it doesn't have any medical value; the FDA approval shows the government thinks CBD does have medical value.