"There's some kind of pain inside from when they were a child. That's where the creation comes from, looking back at that pain. If I see an artist and there isn't any trauma I know if they search they'll find it, it just hasn't been talked about. Childhood trauma pushes that creativity out of people."
Napier-Bell said it wasn't his job to find out what the exact trauma was for the superstar, who tragically died last Christmas Day.
"I never discussed anything with George that touched on his personal life, nor discussed the source of his frequent depression, I just dealt with it as best I could, as I've done with every other artist I ever managed.
"I try to help them find an infrastructure on which they can build success. As a manager, I'm hired to exploit their talent. I'm not a psychiatrist hired to treat the source of it."
He wrote on his Facebook page "Art is a symptom of an artist's inner pain. The manager's job is to commercialise the symptom it produces and help the artist use it to build a satisfactory life.
"To cure the inner pain could well kill the art the manger is there to exploit. George Michael was a truly exceptional artist; probably what he suffered from was equally exceptional."
Now a successful author and documentary maker, Napier-Bell turned down paid interviews with British newspapers to discuss Michael, knowing the singer was always wary of them.
He has spoken to several TV documentaries about working with Wham! but is pleased the narrative is less on Michael's personal life and more on his musical genius.
"His music over-rode everything. You go on his fansites and all they talk about is his music."
While a Nile Rodgers remix of an old b-side Fantasy was released this week, Napier-Bell has no idea what was left in the George Michael vaults.
One long buried item was Wham!'s 1986 concert The Final from London, which was filmed but has never been released.
"George wanted to finish Wham!," Napier-Bell said. "That was it. Wham! was his childhood. A lot of artists aren't that happy with their early catalogue and he was like that."
However Napier-Bell has good memories of the final concert involving one of Wham!'s most famous fans.
"Prince Charles and Princess Diana were right near me. Towards the last few numbers Diana was up on her feet dancing and kept saying to Charles 'Get up and dance, you have to dance!' He was doing this terrible, miserable shuffling of his feet in the last few numbers. I've never seen someone more sad to be at a concert. It was quite mesmerizing."
Napier-Bell's CV includes discovering John Paul Young during a stint in Australia, managing artists including the Yardbirds, T-Rex, Boney M, Japan and Ultravox and co-writing 60s hit You Don't Have To Say You Love Me.
He also managed Sinead O'Connor and was alarmed at her recent Facebook videos telling fans she was suicidal.
"What we call bipolar now used to be called an artistic nature. It's a mix of insecurity and megalomania, you balance between those two things - you're desperate for love and affection and an audience. Every artist has these terrible depressive traits in their character. In the past they took medication or they went and got care and you never heard about it.
"Now with social media you can't keep it private. And with social media now when they come off the stage and they've lost that audience they can get that audience without even having to perform on a stage.
"Sinead is getting that audience she needs by being open about her problems. Sometimes she looks so lost and miserable. It's terrible."