From January to May of this year, 15 people have died from using synthetic cannabinoids, a threefold increase from that period in 2014, the Centers for Disease Control and Prevention (CDC) said in a report issued Thursday. The number of calls to poison centers about the substances has also skyrocketed in the past year, confirming the federal government’s view that this is a growing public health threat that needs to be stamped out.

Synthetic cannabinoids are man-made psychoactive chemicals sprayed on plant material, which is then cut and smoked or eaten. They are alternately referred to and sold as synthetic marijuana, spice, K2, black mamba or crazy clown, according to the CDC report. New types of synthetics are constantly hitting the market, available online and in head shops, making it difficult for the government to outlaw them one by one.

From January to May, poison centers in the United States reported 3,572 calls related to synthetic cannabinoid use, according to the CDC. That’s 229 percent more than the number for that period last year. The majority of calls were for men (80.7 percent), and the median user age (when age was recorded) was 26. (It ranged from 7 to 72.) The 15 deaths related to synthetics in that period compares with five over the same five months in 2014.

Users may experience a high that is said to be comparable to the one from smoking marijuana. Side effects reported to poison centers included agitation, rapid heartbeat, drowsiness, vomiting and confusion.
In addition to calls to poison centers, synthetic cannabinoid-related emergency department visits have risen in recent years, from 11,407 in 2010 to 28,531 in 2011 (the most recent year for which there are data), according to a 2014 report by the federal Substance Abuse and Mental Health Services Administration (SAMHSA).

“They are marketed in a way that frankly does not portray how dangerous they are,” says Donna Bush, a forensic toxicology specialist at SAMHSA, adding that they can be found at convenience stores and gas stations.
“These synthetic cannabinoids were originally designed as research chemicals for use in the laboratory, trying to identify cannabinoid receptors in the brain,” Bush says, not “to be used on the street.” And while the synthetics can in some cases mimic the intoxication experienced when using marijuana, they can also—unexpectedly—be more powerful and last longer. 

“You never know what you’re getting. Every little bag, every little package can be different because there’s no standardization, there’s no quality control. These are all products made on the fly,” Bush says.
The Drug Enforcement Administration has identified hundreds of synthetic substances in recent years. More than 17,000 synthetic cannabinoid-related reports were filed to the DEA’s National Forensic Laboratory Information System in 2013, compared with just 469 in 2010.

A 2012 government survey found that 1 in 9 high school seniors in the U.S. had used synthetic cannabinoids, the second-most commonly used illegal drug for that age group, behind marijuana. That year, President Barack Obama signed into law the Synthetic Drug Abuse Prevention Act, which increases penalties for a number of synthetic cannabinoid types.
A type of synthetic cannabinoid called AB Fubinaca was found in the drug known as Molly earlier this year, when students at Wesleyan University were hospitalized.