Synthetic cannabis, also called K2 or Spice, is a psychoactive designer drug developed from natural herbs and synthetic chemicals, to mimic the pleasurable effects of cannabis. Controversy has arisen about calling Spice and K2 synthetic cannabis because the ingredients contained in these two products are mimics, not duplicates of THC.

First reaching the market in the early 2000s, synthetic cannabis blends were thought to produce their effects through a mixture of legal herbs. This was not the case, instead they contained synthetic cannabinoids that act on the body in a similar way to cannabinoids naturally found in cannabis, such as THC. Cannabicyclohexanol, JWH-018, JWH-073, or HU-210 are large complex varieties of synthetic cannabinoids that are used in an attempt to avoid the laws that make cannabis illegal. Synthetic cannabis has been sold under various brand names, online, in head shops, and at some gas stations.

Extremely large doses of synthetic cannabis may cause negative effects, that are not noted in cannabis users, such as increased agitation and vomiting. “People who use it are idiots. You don’t know what it’s going to do to you”, Professor John W. Huffman, who first synthesized many of the cannabinoids used in synthetic cannabis. Withdrawal symptoms can be similar to those associated with withdrawing from the use of narcotics. Abusers can shown signs of addiction. A study has shown, where an abuser who had previously suffered from cannabis-induced recurrent psychotic episodes, suffered reactivation of his symptoms after using Spice. Psychiatrists treating him have suggested that the lack of an antipsychotic chemical, similar to cannabidiol found in natural cannabis, may make synthetic cannabis more likely to induce psychosis than natural cannabis.