Australian alternative rock band the Vines has canceled all live appearances for the coming months after frontman Craig Nicholls apparently suffered a mental health relapse.

Nicholls, who has been diagnosed with Asperger's syndrome, had a severe swing in his mental condition which, according to a statement posted on the group's Web site, "deteriorated extremely rapidly over the past month to the point where he requires immediate help over an extended period of time."

As a result, the group has pulled out of playing upcoming Aussie summer festivals such as Homebake, Pyramid Rock, Big Day Out and a Japanese tour lined-up for late November.

"We are all absolutely devastated that we've been forced to cancel all upcoming shows as there's nothing we love more than playing on stage before an enthusiastic audience. We ask for your understanding in this situation," comments bandmate Hamish Rosser in the statement.

Big Day Out co-ordinator Sahara Herald Shepherd adds, "The Vines' performances at the 2007 Big Day Out were nothing short of dazzling and they will be greatly missed."

The slate of dates were canned after Nicholls recently failed to board a flight from Adelaide to Perth, leading to the cancellation of a Nov. 8 concert at the Rosemount Hotel. The singer suffered a serious recurrence of his "flight related anxiety," a separate note read on the Web site.

The Vines exploded on the international scene with their 2001 debut "Highly Evolved" (Capitol), which had made them one of the biggest buzz bands of the new millennium. The set debuted at No. 3 in the U.K. and No. 11 on The Billboard 200. But they could not replicate the excitement of that first album, and Nicholls' behavior became increasingly erratic.

The issues came to a head during a disastrous gig at Sydney's Annandale Hotel in 2004, which led to a fall-out with bass player Patrick Matthews, a ban from radio network Triple M, and assault and damage charges laid against Nicholls. The latter charges were dropped when it was revealed that the singer had Asperger's, a mild form of autism.

"Melodia" (Ivy League), the Vines' fourth studio set, peaked at No. 12 on the ARIA albums chart after its release in July this year.