the drug is called 'bath salts' or Mephedrone.
The effects of the drug are similar to the effects of cocaine, amphetamines and MDMA.
If you google 'bath salts, drug' there is heaps on it.
Patient zero in the zombie apocalypse is what I'm betting on. Saying he was crazed and on drugs is exactly the kind of thing the government would say at the start of the zombie apocalypse when the first one shows up.