Like Tesla's promised full self-driving feature, Musk's firms aren't completely autonomous and need a steady— and ideally "super focused" — hand to guide them.

Long-term, heavy ketamine use is associated with memory problems, depression and anxiety. The drug may also cause gastrointestinal problems, abdominal pain popularly known as “k-cramps” and uropathy, which is a blockage in the urinary tract that can lead to infections, or UTIs.