Add Jill Stein to the ranks of public figures questioning Donald Trump’s mental condition.

The Green Party presidential candidate, who is a Harvard-educated physician, said that the Republican White House hopeful may have a “memory problem” during an interview with Politico.

“You know, I don’t pretend to be able to do TV diagnosis, but I think the guy has a problem,” she answered when asked if she agreed with Trump physician Dr. Harold Bornstein’s widely-mocked claim that the real estate mogul would be “the healthiest individual ever elected” to the presidency. “The guy has a lot of problems—physical, mental, emotional, cognitive.”

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Stein pointed to a number of inconsistent positions that Trump has held over the course of the last decade—and even during the 2016 presidential contest itself—on issue like immigration and the Iraq war. In one of the biggest flip flops of the campaign to date, Trump finally admitted last week that President Barack Obama was born in the United States despite the fact that Trump himself had largely made his political name by being one of the “birther” movement’s most ardent and vocal champions.

“It’s hard to, you know, to think too hard about anything Donald Trump says because he will change his mind in the next hour, if not the next day, or whatever,” said Stein, suggesting that Trump’s mercurial policy positions may be more a sign of a mental issue than of political eccentricity.

“Today, suddenly, after five years, he became convinced [the birth certificate is] not an issue. Yesterday it was an issue. It will probably become an issue again for him. You know, the guy may have a memory problem. Who knows what it is? But he’s incapable of having a consistent thought or policy,” she added.

A number of psychiatrists and psychologists have somewhat controversially suggested that Trump may suffer from a number of conditions ranging from narcissistic personality disorder to sociopathy. Such speculation has never been verified in actual medical documents, and Trump did not address his mental acuity in the medical summary he unveiled on celebrity Dr. Mehmet Oz’s show last week.

Hillary Clinton also disclosed new information about her health last week in a bid to reassure voters about her fitness after a pneumonia diagnosis temporarily knocked her off the campaign trail.

Stein and Libertarian candidate Gary Johnson failed to make the cut for the first presidential debate schedule later this month.