According to T-Pain he battled with depression for four years after an upfront conversation with Usher on a plane.

Altering vocals had been done for decades and was bound to become the future of music.. @TPAIN just created a masterclass of technology & pop for my generation https://t.co/dzCmKq6ANr

— diplo (@diplo) June 22, 2021

T-Pain says that his depression battle started after Usher honestly told him, “I’m gonna tell you something, man. You kinda f*cked up music.”
The confession took T-Pain by surprise so much that he thought the statement was a joke, until Usher repeated himself and explained that he thought T-Pain messed things up for the “real singers” by using Auto-Tune for his songs.

T-Pain says he became depressed after Usher told him he "f*cked up music." https://t.co/y6dywyLX7F

— Complex Music (@ComplexMusic) June 21, 2021