Elon Musk says he's bipolar, suffers from unrelenting stress

Tesla and SpaceX CEO Elon Musk on Sunday tweeted about stress and even said that he may be 'bipolar'. "The reality is great highs, terrible lows and unrelenting stress. Don't think people want to hear about the last two," he tweeted. Musk said this in response to a question on his "amazing" life on Instagram.