Sinead O'Connor Cancels Tour Due to Bipolar Disorder: Plus a Look at Stars Who Battle Manic-Depression

Sinead O'Connor announced on Monday that she was cancelling her 2012 tour due to her bipolar disorder. The singer wrote on her website that she is "very unwell" and had been advised by her doctor to not hit the road after her "very serious breakdown between December and March."

Sinead O'Connor cancels 2012 tour due to bipolar disorder, says she is 'very unwell'

In this April 18, 2012 photo, Irish singer Sinead O'Connor is shown during an appearance in Colone, Germany. O’Connor says she has to cancel her tour commitments for 2012 due to her bipolar disorder. The singer made the announcement Monday, April 23, in a posting on her Website.