Police in south Florida have seen a growing number of cases of bizarre and uncontrollable behavior linked to a street drug called flakka, one of the newer chemicals in the booming category of synthetic or designer drugs.

In Fort Lauderdale last month, a man tried to break down the front door of a local precinct and told police officers he was high on flakka. A few weeks later, another man who said he had just smoked flakka impaled himself while trying to scale a fence around the police station. In Lake Worth, a city in Palm Beach County, a man armed with a gun -- and naked -- stood on a rooftop and announced, "I feel delusional, and I'm hallucinating!" He told authorities he had vaped flakka with an e-cigarette.

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Flakka and bath salts are both drugs classified as cathinones. DEA

Flakka is a designer drug that can be snorted, smoked, injected or swallowed. It may also be combined with other, softer drugs such as marijuana.

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Flakka is most typically made from the chemical alpha-PVP, which is a synthetic version of the amphetamine-like stimulant cathinone. Cathinones are chemicals derived from the khat plant grown in the Middle East and Somalia, where the leaves are frequently chewed for a euphoric buzz.

It's the same class of chemical that's used to make so-called bath salts, a drug that was found to be behind a number of alarming incidents, including the case of a man in Miami who allegedly chewed another man's face while high on bath salts in 2012.

The immediate and long-term effects of cathinones can rival some of the strongest crystal meth and cocaine.

Jim Hall, an epidemiologist at the Center for Applied Research on Substance Use and Health Disparities at Nova Southeastern University in Broward County, Florida, told CBS News that cathinones are the next, even more potent class of drugs to take over where MDMA leaves off. MDMA, known widely as Molly, has been the cause of a number of fatalities and the recent round of overdoses that hospitalized a dozen people at Wesleyan University.

Hall says the drug is designed to cause the brain to flood with dopamine, a hormone that helps control the brain's reward and pleasure centers, and then block the transmitters, producing an intense feeling of euphoria. "Normally when dopamine would be released, even naturally or even with other drugs, it then gets reuptaked -- it goes back to its original transmitting neuron," said Hall. "But in this case, its reuptake is blocked so it remains there."

Taking additional flakka while already high -- a practice known as "snacking" -- or combining cathinones with other drugs often leads to serious health complications including rapid heart rate, agitation, extreme aggression and psychosis.

"We're starting to see a rash of cases of a syndrome referred to as excited delirium," said Hall. "This is where the body goes into hyperthermia, generally a temperature of 105 degrees. The individual becomes psychotic, they often rip off their clothes and run out into the street violently and have an adrenaline-like strength and police are called and it takes four or five officers to restrain them. Then once they are restrained, if they don't receive immediate medical attention they can die."

Cathinone use can also cause rhabdomyolysis, which is a melting of the muscle tissue and the release of muscle fibers into the blood stream. This can lead to kidney failure and result in a user needing permanent dialysis.

The drug's name appears to have several meanings, says Hall. The word flaca means skinny in Spanish. "When we first heard the word we thought it was referring to the fact that it's a strong stimulant, almost all stimulants have an appetite depressant quality to them, an almost anorexic quality."

But Hall said flakka is also a Hispanic colloquial word that means a "beautiful, elegant woman who charms all she meets." The drug name also may be associated with a famous hip-hop artist Waka Flocka Flame.

In recent years there's been a rise in the number of national crime lab reports for cathinones, along with a decline in cases involving MDMA, which is the active chemical in both Molly and Ecstasy.

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Hall says designer drugs like flakka are not always pure, which means that frequently the customer and dealer don't actually know what's in the product. Hall says that in 2013 there were a total of 126 reported deaths tied to synthetic cathinone in Florida.

"One of the kind of 21st century trends in drug supply is creating new brand names like flakka and building its popularity and then selling anything," said Hall, who authored a report on the designer drug market in Florida. "Elsewhere in the country [flakka is] actually quite a popular drug. It's often sold under the street name gravel because of its crystal, small, lumped-up appearance that looks like grainy pebbles or gravel in an aquarium."

Hall added that there have been recent reports of a designer drug marketed as flakka in Ohio and Houston as well as Florida.

Flakka is one of a number of cathinone-based drugs that are produced in China and sold online to small-time drug gangs in the U.S. And the business is lucrative. Hall says that with small investment of only a few thousand dollars, a dealer can walk away with as much as $75,000.

"The main issue with this whole category is that the user just doesn't know what they're taking or the strength of what they're taking, and literally they are the guinea pigs," he said. "We're referring to these as the guinea pig drugs. Often the dealer might not even know what they're selling."