There has been an “unprecedented expansion” of the use of synthetic drugs like ketamine, amphetamines, and artificial cannabis, and they're taking up a larger share of the market, according to a new United Nations report. Legal highs and new psychoactive substances (NPS) are now being used more widely than heroin and cocaine, but there's been a particular boom in synthetic cannabinoids. The U.N. reports that the number of legal weed-simulating substances has doubled from 60 in mid-2012 to 110 in 2013.

The United Nations Office on Drugs and Crime found 350 new psychoactive substances in 90 countries at the end of 2013, but none of them are under any form of international control. That lack of international oversight is one reasons why synthetic drugs have been able to thrive. One of the biggest findings from the report is that khat, the plant-based psychoactive drug, is reaching far beyond the East African countries where it’s traditionally consumed, and is being trafficked to the U.K., the Netherlands, and the U.S.

From the 2014 Global Synthetic Assessment, UNODC

Earlier this month, the Drug Enforcement Administration (DEA) ramped up their crack down on the synthetic drug market — best-sellers include “Molly,” “bath salts,” and “spice” — by serving hundreds of arrest warrants across 25 states. The DEA are also attempting to curb the recreational use of prescription drugs. The agency said that every month, five new different drug compounds enter the market, and that they’re quickly made widely available.

From the 2014 Global Synthetic Assessment, UNODC

North America has seen skyrocketing rates of seizures caused by amphetamine-type stimulants, according to the report. The number of methamphetamine seizures has gone from around 10,000 in 2007 to just under 60,000 in 2012. The U.S. has also seen an enormous rise in the number of dismantled meth labs, which suggests an increase in both the production and sale of the drug (and that Breaking Bad didn't reach is crazed popularity until after 2010). 

While the U.S. and Canada make up one of the largest markets for new psychoactive substances in the world, the unknown ingredients found in most synthetic drugs are causing serious health problems. Calls to poison control centers over synthetic cannabis increased by 80 percent between 2010 and 2012.