THE Vines' frontman Craig Nicholls, who put Australian rock back on the international stage after 20 years, has been diagnosed with a disorder.

Nicholls' condition, known as Asperger's syndrome, was revealed in Balmain Local Court yesterday when charges of assault and malicious damage were unconditionally dismissed.

The charges followed an incident at the Annandale Hotel on May 27 when the singer-songwriter allegedly kicked a photographer's camera during a performance for radio station Triple M competition winners.

After the brief hearing, an elated Nicholls walked out of court holding up his arms and said: "I'm free."

He attended the 10-minute hearing with his brother Matt and managers Andy Kelly, Andy Cassell and Pete Lusty.

US and European tours to support the release of the band's second album Winning Days were cancelled in June to allow Nicholls to recover from "mental and physical exhaustion".

Despite years of examination by psychologists and psychiatrists, Nicholls was finally diagnosed after his management team were alerted to the existence of Asperger's syndrome (AS) by one of the band's crew members.

They engaged a world authority on autism spectrum disorders, Professor Tony Attwood who is based in Brisbane, to examine Nicholls.

His family completed two extensive surveys relating to Nicholls' behaviour during childhood, which are used to diagnose the syndrome, and Professor Attwood confirmed the condition after meeting the singer in August.

Nicholls' behaviour has perplexed fans and critics for the past three years.

The gifted songwriter became more erratic and abusive on and off stage as the band's success and touring commitments increased.

Professor Attwood said yesterday extensive touring would cause extraordinary stress and eventual nervous breakdown to AS sufferers because of their inability to socially interact and the changes to their environment.

But sufferers can excel at music, mathematics and mechanical skills.

"Craig lives for his music. It's his therapy, it's the way he communicates, it's his life," Professor Attwood said.

The Vines' management said Nicholls and his fellow band members – Patrick Matthews, Hamish Rosser and Ryan Griffiths – would now start work on the band's third album.

They have sold more than two million copies of their debut Highly Evolved and follow-up Winning Days since bursting on to the international arena in 2002.

"He can't wait to get back into the rehearsal studio and we can't wait to hear what he's going to come up with," Mr Kelly said.

The Vines will be unable to undertake major tours because of Nicholls' condition but plan to perform occasional concerts.

Capitol, their record label in the US, and EMI, their Australian label, have confirmed their support for the band and will release the new album.