Mary Trump, a clinical psychologist who is Donald Trump's niece, told MSNBC that her uncle has "severe untreated psychiatric disorders."
In an interview on Sunday, Mary Trump reflected on her uncle's recent debate with Vice President Kamala Harris.
"She inflicted upon him a narcissistic injury so deep he will never recover from it, but I'm actually not being hyperbolic," she explained. "Donald will revisit those moments for the rest of the campaign and probably for the rest of his life."
MSNBC host Michael Steele noted that Donald Trump seemed unable to give cogent answers to basic questions in interviews.
"What the hell is his problem?" Steele asked.
"First, just for a second to allude to something you said earlier, Donald does have no ideology," Mary Trump replied. "He has no core self at all, actually."
"In terms of what we're seeing happen with his inability to hold a thought, this is somebody who has severe, untreated psychiatric disorders going back decades," she continued. "So, he is unraveling. This is what happens when you don't treat illnesses. They worsen."
Mary Trump said some pundits were doing a disservice to the public by "imbuing meaning into his statements that does not exist."
"That is giving him a huge advantage and essentially just making up out of whole cloth whatever they want him to mean," she noted. "And it's very dangerous."