Tesla stock drops after Elon Musk describes his 'excruciating' year

SAN FRANCISCO, California -- Tesla shares dropped nearly nine percent after the New York Times reported stress is taking a heavy toll on CEO Elon Musk.

In the devastating report, Musk told the Times he has been working up to 120 hours a week and taking Ambien to get to sleep.

Musk created a stir last week when he tweeted that he wanted to take Tesla private.

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Tesla closed at $305 a share, down 30 points Friday.

This week alone Tesla has lost $8 billion in shareholder value.