The U.S. market for CBD products — most often derived from hemp, another plant in the cannabis family — grew by more than 80 percent in 2018, to about $591 million, according to Chicago-based Brightfield Group, which does market research in cannabis-related industries. The products gained momentum with anxiety-ridden millennials in search of a solution more natural than the Xanax of previous generations. But now the products are becoming popular with older age groups as users look to address the illnesses, aches and pains associated with aging without pharmaceuticals.