Synthetic cannabis’: a dangerous misnomer

September 2021

What is ‘synthetic cannabis’?

What then are these drugs? The term covers a vast array of chemicals. They first emerged in 2004, and over the past decade no less than 280 new substances were identified as ‘synthetic cannabis’. The drugs were designed to give similar effects to cannabis, and are typically sprayed onto a herb to give the appearance of cannabis. They are not synthetic THC (the active ingredient in cannabis), or even structurally related to THC. While both THC and SCRAs act on the cannabinoid receptors, many commonly used SCRAs are 10-100 times more potent than THC. They also have a great many other physical and psychological effects that are not seen with cannabis.

What are their toxic effects?

We know that the toxic effects of SCRAs are far more severe and extensive than those of cannabis. Their most prominent characteristics are wide ranging effects on the heart and circulatory system. These include raised blood pressure, heartbeat arrhythmia, accelerated heartbeat and chest pain. They have also been known to cause stroke. Cases of acute kidney failure have also occurred, probably due to malignant hyperthermia, a dangerous increase in body temperature caused by SCRAs. SCRAs have also been known to induce sudden, catastrophic, respiratory failure.

Most importantly, there are known cases of death due to SCRA toxicity, probably due to their toxic effects upon the cardiovascular system. Indeed, at NDARC we have documented such cases in Australia. Older users appear to be particularly at risk.

These drugs have also been associated with a range of severe psychiatric consequences, including delirium and acute psychosis. Indeed, there have been widely reported mass intoxications requiring widespread hospitalisations, such as the 2016 ‘zombie’ outbreak in New York City.

How do these effects differ from cannabis?

We know that the clinical profiles of SCRAs and cannabis differ markedly. The most important difference is that there have been no documented deaths from THC toxicity. In contrast, such deaths do occur from SCRA toxicity. Overall, the effects of SCRAs such as cardiac arrhythmia, stroke, hyperthermia and acute kidney injury are not profiles we expect to see with cannabis. What then they do look like? They look remarkably like cases of psychostimulant toxicity. SCRAs are not psychostimulants, but their general clinical profile is one we would typically expect to see in hospital presentations for a drug such as methamphetamine.

In recent years we have also seen emerging evidence that SCRAs can induce a more serious and complex withdrawal syndrome than that seen with cannabis. Their high potency also increases the likelihood of dependence.

What can we do?

These drugs are already illegal, so what else can we do? First, as has been argued here, terminology matters. There is confusion amongst the general population about these drugs, and we need to be consistent in using the term SCRAs. We also need to make clear to users of these drugs that they are not cannabis substitutes, and that switching to that is more akin to switching to methamphetamine. Finally, we need to develop specific detoxification regimes and treatment options for SCRAs. This may involve the development of new pharmacotherapies for the treatment of SCRA dependence or withdrawal.


SCRAs are an entirely different drug class than cannabis. To use terms such as ‘synthetic cannabis’ or ‘synthetic marijuana’ is misleading and even dangerous. The one thing ‘synthetic cannabis’ is not is synthetic cannabis.

Read the full article here.