Kanye West Says a 'Sprained Brain' Doesn't Get Treated Like an Ankle

Kanye West described in vivid detail what it's like to have a bipolar episode, and he grouses people just don't get it ... and actually made it way worse for him.

Ye opened up about his mental health struggles to David Letterman for his Netflix show, 'My Next Guest Needs No Introduction' -- and we got hold of the footage where he tries to get people to imagine a sprained ankle and then transfer that concept to a sprained brain.

Listen to Kanye ... it's a revelation when you think of a people bearing down on a sprained ankle, causing pain and exacerbating the injury. Now, think of doctors and society doing the same sort of thing to a cerebrum.

TMZ broke the story ... Kanye had what seemed like a nervous breakdown back in 2016, which turned out to be a bipolar episode. He was handcuffed to a hospital bed and left alone, which -- as he explains in this clip -- only made things worse.

He says he's opening up about all this to start a conversation about the way we treat bipolar disorder ... and has been applauded for his efforts in speaking about it so candidly.

The entire season -- which also includes interviews with Ellen DeGeneres and Melinda Gates -- drops Friday on Netflix and we're told through it all, Kanye is for the most part very cogent and clear.