Tesla shares fell nearly 9% in midday trading on Friday to $305.61 after the New York Times story published Thursday evening. In the interview, Musk said he has been working 120 hours a week as Tesla tries to fix production problems with its much-anticipated Model 3, a car that is intended for the mass market and is critical for the electric car company’s future.

But the personal cost appears to have taken a toil on Musk. In the interview, he calls the past year “excruciating” and “the most difficult and painful year of my career” while also acknowledging that he often relies on Ambien to help him sleep. The Times reported that some Tesla board members are concerned about his use of sleeping pills.

Musk also said that no one reviewed his infamous Aug. 7 tweet in which he said: “considering taking Tesla private at $420. Funding secured,” which sent the company’s stock soaring. The Twitter comment reportedly prompted the Securities and Exchange Commission to seek more information from Tesla about the veracity of Musk’s claim and his decision to reveal a potential blockbuster deal on the social network instead of more formally through the SEC.

Other recent actions that have concerned investors include Musk calling a diver who helped rescue Thai children trapped in a cave a “pedo” and berating analysts during a conference call.

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In a tweet on Friday, CNBC news anchor Jim Cramer called the latest interview “devastating” and said “the safest thing for Musk right now is a medical leave.”

Devasting New York Times piece filled with new facts. We know that the safest thing for Musk right now is a medical leave.. I would insist on it. https://t.co/kRm9Ye3i6l

— Jim Cramer (@jimcramer) August 17, 2018

Update: Friday at 1:10 PM PST.

Tesla shares were down 8.93% to 305.50 at end-of-day trading on Friday.