Billionaire Elon Musk says he might be bipolar.  The Tesla and SpaceX CEO responded to a tweet Sunday where someone asked about the ups and downs of his life.  Musk wrote: "The reality is great highs, terrible lows and unrelenting stress. Don't think people want to hear about the last 2."  Asked if he was bipolar, Musk said "yeah" but added that maybe he hadn't been medically diagnosed.  

Musk opined that perhaps the real problem is quote, "getting carried away in what I sign up for."

Photo: AOL