Focus (Methylphenylethylenedioxymetamphetaexpialidocious) was originally developed as a cure for Attention deficit disorder. It functioned as a neural attention enhancer and was popular on Earth in the mid 21st century as a student study aid and recreational drug.
It was sold illicitly in complicated packages or 'designs' which required immense concentration to open, thereby necessitating the use of the drug in the first place.
Apart from the original intended curative effect, it is difficult to justify the overall benefits of any drug which turns its abusers into mindless morons, however, as has been widely claimed, the discovery of Emti technology may not have been made at all if Milus Blondel hadn't been a devotee.
See How? Fascinating!.