- Flakka, a synthetic drug, can cause health problems and violent behavior
- It was a huge problem in 2014 and 2015 but now has largely vanished
- One expert largely credits a Chinese drug ban that went into effect in October
(CNN)In late 2014, the synthetic drug known as flakka exploded on the scene and prompted such bizarre, violent behavior that it quickly became shorthand for lunacy. The street drug, which is similar to cocaine but much cheaper and more potent, has been called "$5 insanity."