Spotlight on… Synthetic cannabinoids

What are synthetic cannabinoids?
Synthetic cannabinoids (or synthetic cannabinoid receptor agonists) is the name given to a diverse range of substances that act on the same brain receptors as tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis.

Typically, synthetic cannabinoids are sold as ‘herbal smoking mixtures’. Synthetic cannabinoids have also been distributed as powders, tablets and products that look like cannabis resin. In recent years, new dosage forms, including e-liquids for vaping using electronic cigarettes, as well as paper impregnated with synthetic cannabinoids, have appeared on the drug market.

What is happening in Europe?
Since 2008, many synthetic cannabinoids have been detected in Europe in hundreds of different products, frequently sold as ‘legal’ replacements for cannabis, although their effects are often very different.

The prevalence of use in the general population appears low but may be higher in socially marginalised populations, such as the homeless and people in prison. Synthetic cannabinoids are attractive to these groups because they produce strong intoxication at a relatively low price, and, in the case of prisoners, are not detected in most routine urine testing.

While cases have been rare in Europe, during 2015 more than 200 people were hospitalised over a few days in Poland after smoking a product called ‘Mocarz’. Because these products rarely state their ingredients, most people will be unaware that they are using a synthetic cannabinoid. More recently, a total of 21 deaths linked to 4F-MDMB-BICA were reported in Hungary over a four-month period in 2020.

What problems are associated with their use?
Many of the synthetic cannabinoids sold on the drug market are more potent than THC. This may explain why the harmful effects of synthetic cannabinoids, such as severe and fatal poisoning, may be more common than for cannabis. Another important factor is likely to be the large doses people may be exposed to.

Smoking mixtures are made by spraying synthetic cannabinoids onto plant material. This crude process can result in mixtures that contain large amounts of highly potent cannabinoids, as well as ‘hot pockets’ within individual products where the cannabinoid is highly concentrated. These factors make it difficult for users to control their dose and they can inadvertently take a toxic amount. Smoking mixtures have caused a number of mass poisonings in the United States, while paper impregnated with synthetic cannabinoids can pose a similarly high risk of poisoning because the amount of synthetic cannabinoid can be unevenly distributed.

Existing responses and implications for the future
The potential for outbreaks of intoxication and other harms posed by these substances highlights the importance of maintaining and strengthening the identification, reporting and monitoring of any serious adverse events associated with their use. In this respect, early warning systems play an essential role in identifying and responding to harms caused by synthetic cannabinoids. The EMCDDA have issued a number of risk communications addressing a range of public health concerns related to synthetic cannabinoids, and, since 2016, it has subjected a number of synthetic cannabinoids to a formal risk assessment.

Drug services need to focus on the individual, their symptoms and the setting in which use takes place rather than on identifying the specific substance used. It is important to recognise that the needs of people who use synthetic cannabinoids may differ significantly from those of cannabis users.

Prisons may require special approaches to synthetic cannabinoids, which pose threats to both health and security. Collecting data on the extent of the problem and developing guidance and training for staff to manage such drug use are important steps. Prison staff need to be prepared to deal with the adverse health effects of using synthetic cannabinoids, which in extreme cases may require transfer to hospital, but can also be long-lasting and require ongoing management. Education, harm reduction advice and treatment for people in prison who have developed dependence on synthetic cannabinoids should also be provided.