According to Helmut M'ller, head of Berlin's Kurt Singer Institute for Musical Health, there are quite a number of substance abusers among musicians, who take drugs to get rid of their stage fright.

"Between 25 and 30 per cent of musicians regularly take tablets or alcohol to combat performance anxiety," Times Online quoted him, as saying.

Professor M?ller is not talking about the usual rock and rollers, but about the plaid shirt, black coat and tie-wearing musicians, who guzzle beta-blockers - medication that is usually prescribed for patients with heart problems.

Concert musicians have been able to keep their substance abuse under wraps for quite sometime, and drugs that they use are nowhere the same as those used in competitive sport.

Substance abuse by concert musician only came to light when a horn player from the Berlin Philharmonic confessed in a new documentary film to needing drink before performing.

"You go for tranquillisers or beer. With me it was beer," said Klaus Wallendorf, who had been advised by his teacher to drink a beer if he could not reach a note.

"Then you drink two beers and it goes smoothly so you think you should do it all the time," Mr Wallendorf, spoke in Thomas Grube's film Tour of Asia, which accompanies the Philharmonic and its chief conductor, Sir Simon Rattle, on a groundbreaking 2005 tour.