By Benjamin Plackett, Inside Science

There is an ongoing competition of bureaucratic one-upmanship between the U.S. government and renegade pharmacists. The government is playing defense. When they ban a variation of a drug, pharmacists then quickly create a newly formulated and therefore legal variation.

The drug makers are shrewd chemists. They know if they alter the chemical structure of an illegal drug in a simple way, it technically becomes a new substance and consequently outside any federal regulation until the authorities catch up. It's a high-stakes game of whack-a-mole. These drug variations are often called synthetic marijuana and its developers and users make their money and get their highs in this legally ambiguous arena.

New research published in the journal Drug and Alcohol Dependence last month shows that among high school students in the U.S., white males are most likely to use these strains of manufactured marijuana — though the study author suspects this pattern may not hold true in large cities. In 2011, use of the substance among high school seniors was at 11.4 percent, second only to traditional marijuana as the recreational drug of choice.

The study, led by Joseph Palamar, an assistant professor in the department of population health at New York University, analyzed data collected from an annual questionnaire called Monitoring the Future, which surveys American secondary school students. The data enabled Palamar to look at synthetic marijuana use in 48 states by over 11,000 students from 2011 to 2014.

Throughout the sample, male students were reliably more likely to dabble than female students. Black students were 42 percent less likely to report use than their white counterparts.

The gender disparity didn't surprise Palamar, but before looking at the data he thought the drug might have been popular among minorities.

"If you're a minority, you're more likely to get stopped and frisked by the police and so I was interested to see if those groups would be more likely to go for synthetic weed," he said.

If you're found in possession of the most recent version of the compound — and assuming the government hasn’t caught up yet — then it's still legal.

Synthetics are also harder to detect in urine tests, said Jenny L. Wiley, a cannabinoid pharmacology expert at the nonprofit research organization RTI International, who was not involved with the study.

"That's why people take these drugs instead of marijuana," she said.

The drug's prevalence among teenagers does not surprise experts, though they do say it is cause for concern. It is a drug clouded by a haze of persistent untruths and misconceptions, which starts with its name.

Many major news outlets habitually call it synthetic marijuana, a legal high or fake weed, but they shouldn't, explained Wiley.

"It's one of my pet peeves," said Wiley, "Much of it isn't legal anymore and when people call it synthetic marijuana it implies they're made up of the same sort of chemicals as marijuana. They really aren't."

Wiley would rather people use the term "synthetic cannabinoid."

No government agency controlled or regulated synthetic cannabinoids before 2010, explained Federal Drug Administration spokesperson Jeff Ventura in an email. But things have changed since then.

"Congress has taken steps to ban many of these substances at the federal level, and the administration has supported such efforts," he wrote, "At least 43 states have taken action to control one or more synthetic cannabinoids."

The main chemical in traditional cannabis is called tetrahydrocannabinol (THC), which stimulates receptors in the brain to release dopamine, generating a sense of euphoria. The chemicals in synthetic cannabinoids may bind to some of these same receptors, but the vast majority are not chemically parallel to THC, said Wiley. That means they could also bind to other receptors in the brain with unknown effects.

Wiley's main concern about using the term "fake weed" is safety related — it makes at least some people think that taking synthetic cannabinoids isn't risky.

"There is a perception that cannabis is safe and therefore an assumption that synthetic cannabinoids are too," she said, "but we don't know which other receptors they could be hitting."

One school of thought that says the chemicals in synthetic cannabinoids could stimulate receptors associated with kidney failure, said Wiley. Though she adds that the dangers of the drugs are essentially unknown, largely because new ones keep coming out to avoid regulation — it's hard for both law enforcement and researchers to keep pace.

Even with the better-known synthetic brands like Spice and K2, you can't be sure which chemicals are in the product.

"You don't know what you're buying from them, whether it's legal or not. You're trusting them," said Wiley.

Since 2011, nearly 19,000 people in the U.S. reported to poison centers after taking a synthetic cannabinoid, with 354 occurring in January of this year, according to statistics from the American Association of Poison Control Centers.

Just like regular marijuana, synthetics can be inhaled with an e-cigarette-like device. Wiley says some of the chemicals in the e-liquids have a tendency to crystallize, which increases the concentration of the drug.

"That's going to pack a bigger punch," she said, "You can think you're experienced and then all of a sudden it hits you. That makes it more dangerous."

Palamar agrees with Wiley that there is a wrongful assumption that synthetic cannabinoids are safe by association with marijuana.

"I don't think there are tens of thousands of marijuana poisonings. There's definitely something going on with synthetics."

"A lot of people think it's just like weed until they try it," he added, "If people were more wary about it there might be fewer poisonings."