Her announcement comes after months of erratic behavior, including the admission of drug use and a quickie wedding to therapist Barry Herridge in Las Vegas in December, followed shortly after by the announcement of a planned divorce, and then a reconciliation.
"With enormous regret I must announce that I have to cancel all touring for the year as am very unwell due to bipolar disorder," a message on O'Connor's Web site said. "As you all know I had a very serious breakdown between December and March and I had been advised by my doctor not to go on tour but didn't want to 'fail' or let anyone down as the tour was already booked to coincide with [my] album release. So very stupidly I ignored his advice to my great detriment, attempting to be stronger than I actually am. I apologize sincerely for any difficulties this may cause."
The 45-year-old recording artist said she hopes to appear as scheduled at the Curtis Mayfield tribute at New York's Lincoln Center in July.
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