Mental illness a growing concern on tennis tours

— -- For Petra Kvitova, everything changed thanks to a single, simple text message. It was February, and the Czech tennis standout had just landed in Doha, Qatar, for the next stop on the hectic tennis circuit. Seven months after winning her second Wimbledon title and four months after clinching another Fed Cup, she ought to have been on a high. But something was wrong. She felt empty, listless and, most worrying of all, unable to explain why.

Kvitova was preparing for her second-round match against Serbia's Jelena Jankovic when she checked her text messages. Among them was one from her longtime coach, David Kotyza.

"I think it's a good idea to take a break," he said. "Otherwise, I don't know how long you are going to keep on feeling this way."