Synthetic cannabinoids, similar to tetrahydrocannabinol (the psychoactive ingredient of marijuana), bind to cannabinoid receptors in the human brain, triggering similar neurophysiological effects. These synthetic cannabinoids are marketed in incense mixtures as "legal highs" via the Internet and are "flooding the market", as Siegfried Knasmüller from the Institute for Cancer Research at the MedUni Vienna warns.
"The substances are directly active, in other words they are not activated via enzymes that metabolise foreign substances", explains Knasmüller. "The respiratory organs and the digestive tract especially are subjected to increased concentrations of these drugs. Our investigations on human cell lines in the laboratory have shown that synthetic cannabinoids, in the high concentrations found in cells in the oral cavity or in the lungs, for example, are likely to trigger damage to the DNA that may have significant consequences for the consumers of such substances. They damage chromosomes, and this is directly associated with cancer."
Effects on consumers cannot be quantified
Synthetic cannabinoids bind very differently and some have an effect even in very small quantities. Consumers have absolutely no information about the varying levels of effect, since they are unaware of the detailed composition of synthetically manufactured drugs. Even with "known" products, the type and quantity of ingredients added change constantly. The risk of an unwanted overdose is correspondingly great. As a result, there have been repeated cases of damage to users' health or poisoning, and in some cases users have even died.
Between 2005 and 2012, the European Union's early warning system registered just under 240 new psychoactive substances that were disguised as incense blends, bath salts or plant fertiliser, and around 140 of them contained synthetic cannabinoids.