Michigan has outlawed synthetic marijuana, the Grand Rapids Press reported Oct. 1.

Banned in parts of Europe, synthetic cannabinoids are sold as a mixture of spices and herbs under a variety of names, such as “K2,” “Spice,” and “Mr. Smiley.” Users smoke the mixture in joints or pipes for a marijuana-like high. 

Made primarily in China and Korea, the mixtures are sprayed with a synthetic compound similar to marijuana's psychoactive ingredient, THC. There had not been restrictions on their use in most of the United States until recently.

Although there is not a lot of research on K2, medical experts have been concerned by its link to increased heart rate, symptoms similar to schizophrenia, and to paralysis.

The Michigan law makes possession or use of K2 a misdemeanor.

Similar bills are under consideration in Idaho and Pennsylvania.