(March 18): 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.

Musk said he takes the drug as prescribed periodically to treat what he described as “chemical tides” that lead to depression-like symptoms. Doctors can prescribe ketamine to treat pain and depression and at higher doses, the drug acts as a sedative. It can also cause hallucinations, and overdosing can lead to unconsciousness and dangerously slowed breathing, according to the US Drug Enforcement Administration.

An article in the Wall Street Journal in January said that executives in the Tesla and SpaceX chief executive officer’s companies had grown concerned about his recreational drug use. Musk responded that he hadn’t failed drug tests and, in a post on his X social network, that “whatever I’m doing, I should obviously keep doing it!”

Ketamine can be infused in a medical setting, or a close relative of the drug, Spravato, can be taken as a nasal spray for treatment-resistant depression. Musk didn’t give additional details on his prescription in the interview.

X had cancelled a planned partnership with Lemon following the interview. Lemon, speaking on the Pivot podcast with Scott Galloway and Kara Swisher, said that Musk disliked his line of questions, including those about Musk’s ketamine use. Musk said in a post on X at the time that he didn’t like the Don Lemon Show’s approach, which he said was “basically just CNN, but on social media.”