The 43-year-old, whose full name is Melanie Brown and performed as Scary Spice, told The Sun on Sunday that she's been through an "incredibly difficult" six months in which she worked on an autobiography.
"It has been unbelievably traumatic reliving an emotionally abusive relationship and confronting so many massive issues in my life," she said.
Brown posted a link to a US government website to Twitter explaining post-traumatic stress disorder (PTSD) after she was diagnosed with it following an abusive relationship.
"Knowledge is power," the singer wrote.