Things improved for Susan in 2012 when she was diagnosed with a form of autism called Asperger’s Syndrome.
"That was just a relief for me, though, because for years I thought I had something a bit more serious, you know? So that took it off my shoulders a bit," she said, explaining that she had previously thought she had "quite serious brain damage."
"[With] Asperger's you just have to make people aware that sometimes you have to go at a certain pace, don't be too bombarded with things. At the very beginning I was too bombarded," she explained.
"It's nothing to be ashamed of. Everybody has something. I mean, a flaw, if you like. But you shouldn't be ashamed of it. It's something that you bring out in the open in the hope that you help other people. I like to feel I'm the voice for people who have been the underdog, and I wanted to try and prove myself."
Susan explained that her diagnosis means she sometimes finds it difficult to communicate in the same was as other people.
"If people give you a bit more time — like you did, thank you — I can eventually get my words out and I'm OK," the singer explained.
Susan, who has recently released her album TEN, is about to tour the UK, says she feels better than ever.
"I just want to keep entertaining people," she told Tracey. "Making albums. Touring. I'm as happy as anything."