CHAPTER 18: Synthetic Cannabinoid Receptor Agonists (SCRAs)

The first illicit use of cannabimimetics did not come to notice until about 2008. These substances had been evaluated in academic and pharmaceutical laboratories as potential medicines which would have some of the desirable properties of cannabis but without the unwanted psychoactive effects. Their appearance as drugs of misuse was unanticipated since most believed that cannabis was cheap and plentiful and there would be little scope for synthetic derivatives. This attitude ignored the fact that synthetic substances might have a far higher potency than THC (Δ⁹-tetrahydrocannabinol), the active principle of cannabis and, at least initially, would not be controlled nor detected by urine drug-screening systems. To a large extent what are now known as synthetic cannabinoid receptor agonists (SCRAs) have chemical structures quite distinct from THC. Some of the earliest SCRAs were naphthoylindoles, naphthoylpyrroles, naphthylmethylindenes, phenylacetylindoles and cyclohexylphenols. As legislatures attempted to control SCRAs, a rapid structural evolution occurred facilitated by the fact that cannabimimetic activity could be found in a diverse range of compounds. SCRAs represent the largest group of new psychoactive substances (209 as of late 2020) reported to the European Monitoring Centre for Drugs and Drug Addiction. These substances have tested the limits of what can be achieved by generic control. In view of their structural diversity and unwieldy formal names, code names have been developed.