George Clooney has revealed how he contemplated suicide to escape horrific pain he was experiencing after suffering a brain injury in an accident while shooting a scene for a forthcoming film.

The 44-year-old star of Ocean's Eleven and From Dusk Till Dawn said he battled against excruciating headaches and serious memory loss after falling and banging his head while filming Syriana, a thriller set in the Middle East which is due out in January. The actor was tied to a chair for a scene in the $50m Warner Brothers film, based on former CIA agent Robert Baer's book See No Evil.

'There was this scene where I was taped to a chair and getting beaten up. The chair was kicked over and I hit my head,' said Clooney.

'I tore my dura, which is the wrap around my spine that holds in the spinal fluid. But it's not my back; it's my brain. I basically bruised my brain. It's bouncing around my head because it's not supported by the spinal fluid', the former ER star added.

He suffered constant pain and splitting headaches as doctors initially could not identify the problem. He could not take painkillers in case he became addicted to them; several members of his family had suffered that fate. Instead, he had to prepare mentally through therapy that taught him to forget his own pain.

'Before the surgery it was the most unbearable pain I've ever been through, literally where you'd go, "well, you'll have to kill yourself at some point, you can't live like this",' explained Clooney. He blamed himself because he had piled on 38 pounds in a month to play the main role of Baer.

After the accident, Clooney began trying to encourage his memory to return by doing repetitive counting exercises, and even had to write his lines on scraps of paper for his next project, as director-actor in Good Night, and Good Luck.

Despite doctors' initial puzzlement, a neurologist eventually identified the problem and Clooney underwent a series of operations that banished his headaches.

The last 12 months had been 'the worst year I've ever had,' Clooney said, because of his brain injury and the deaths of his grandmother, brother-in-law and dog.