Marijuana—often called pot, grass, reefer, weed, herb, Mary Jane, or MJ—is a greenish-gray mixture of the dried, shredded leaves, stems, seeds, and flowers of Cannabis sativa—the hemp plant. Most users smoke marijuana in hand-rolled cigarettes called joints, among other names; some use pipes or water pipes called bongs. Marijuana cigars, or blunts, are also popular. To make blunts, users slice open cigars, remove some of the tobacco, and mix the remainder with marijuana.3 Marijuana also is used to brew tea and sometimes is mixed into foods.
As a result of scientific research, we know that addiction is a disease that affects both brain and behavior.