Musk Defends Ketamine Prescription, Denies Illegal Drug Use

• Musk defends his ketamine prescription, says it helps manage "negative chemical state" like depression • Argues investors shouldn't worry as long as his companies execute well • Details allegations from Wall Street Journal report that Musk used illegal drugs like LSD, cocaine, ecstasy • Ketamine is a prescription drug used to treat some patients with depression • Musk denies abusing ketamine, says he has a doctor's prescription and doesn't use too much or he can't work