The music mogul struggled to cope with his many television commitments, according to an updated new chapter in Tom Bower's book Sweet Revenge, The Intimate Life of Simon Cowell.
Cowell's workload now includes The X Factor in the UK and US, Britain's Got Talent and America's Got Talent.
Due to his manic lifestyle, Cowell reportedly had to step away from some of the audition process for The X Factor in the US as it was turning him into a "weird vampire".
Bower claimed that Cowell confides in his good friend and colleague Louis Walsh.
He allegedly told Walsh: "I don't want any more tablets and pills. I'm cutting out the lot, including cigarettes.
"I desperately need peace. I'm craving normality. I've got to work out my demons and come out of it.
"I have to get back to where I was years ago. I had to stop reading texts at three in the morning and making calls later and later. I wanted peace."
The 52-year-old also reportedly revealed that the constant flying between the UK and US added to his troubles.
He said: "My life was like a night shift. I'd forgotten the sensation of the morning."