The 39-year-old singer has been close friends with the 'Heartless' rapper for many years, and has said that following Kanye's social media outbursts - which have seen him voice his support for controversial president Donald Trump, as well as claim the 400 years of black slavery was a ''choice'' - many people have tried to label him with a mental health condition.
And whilst John ''clearly disagreed'' with the things Kanye posted, he insists what's ''going on in his brain'' is no-one's business.
Speaking to the Wall Street Journal magazine, the 'All of Me' hitmaker said: ''A lot of people have tried to armchair-diagnose him, but I leave it to him and his doctor to discuss what's going on in his brain. Clearly I disagreed with some of the things he was saying, and I was worried that his saying it might empower some of the wrong forces, might be really demoralising for people who looked up to him and thought of him as a leader.''
John's comments come after Kanye, 41, previously claimed he had been diagnosed with bipolar disorder, but said he thinks he was just battling with ''sleep deprivation'' rather than the mental health disorder.
He said: ''What I think is we don't need sentences, we need pardons. We need to talk to people. I was diagnosed with bipolar disorder, I was connected with a neuropsychologist that works with the athletes in the NBA and NFL. He looked at my brain. I wasn't actually bipolar, I had sleep deprivation which can cause dementia 10 to 20 years from now when I wouldn't even remember my son's name.''
But the rapper - who has North, five, Saint, two, and Chicago, nine months, with his wife Kim Kardashian West - previously revealed he had learned to embrace his bipolar.
He explained: ''I think it's important for us to have open conversations about mental health - especially with me being black. Because we never had therapists in the black community. We never approached taking a medication. I think it's good that when I had my first complete blackout at age five, my mom didn't fully medicate me. Because I might have never been 'Ye. And there's times where at least I'm happy that I know [I'm bipolar.] Like, even like for this interview, I knew I wanted to stay in a calm state.''