The singer, who shot to fame at 18, told the Daily Mail: "I've had a bit of a breakdown and been very unwell."
Melua admitted that it was a "sensitive subject", but explained: "The fact is, I just couldn't go on any longer. I knew there was something seriously wrong because I was just sitting in a chair staring into space."
Melua was briefly hospitalised as a result of her breakdown, but is now getting back into her music.
"I've eased myself back into work over the last few weeks and I start a European tour next month," she said. "I am also writing some new songs."