Elon Musk said that his prescribed use of ketamine alleviates periods of low mood and is in the best interest of investors in Tesla Inc. and the other companies he runs. For Wall Street, “what matters is execution,” Musk said in an interview with former CNN anchor Don Lemon streamed Monday on YouTube. “From an investor standpoint, if there is something I’m taking, I should keep taking it,” he said referring to Tesla’s success. (From "The Don Lemon Show" on Youtube)