What are the negative side effects of smoking synthetic weed? A brand like fusion, for example. Thanks before hand!

Synthetic Marijuana. There are multiple forms, and names for these designer drugs, are illegal in many states, an can lead to instant death from irregular heat beat. Vomiting, elevated blood pressure, seizures, and thousands of emergency rooms, and drug hotline calls about "bad trips" have occurred because of a "group" of drugs known as synthetic marijuana.
K2, Spice, etc. In addition to altering one's mental state (which can make a person prone to say or do things they might not otherwise), synthetic weed has been linked to a 3-fold increase in psychosis (hearing things, seeing things, paranoia, etc.) over "standard" marijuana (in which the rate of psychosis is roughly 10%). For some people, the psychosis may not resolve as the drug's effects wear off.