Here are 7 brutal comments from experts about Donald Trump's mental stability

President Donald Trump has turned back to attacking former Vice President Joe Biden after super Tuesday states delivered higher than expected wins for the new Democratic front-runner. Trump has turned to attack Biden's mental acuity, an argument that the president likely doesn't want to have given the number of experts who have speculated the president doesn't have the mental fitness to lead the nation.

Last year, more than 350 psychologists and mental health experts sounded the alarm that the president's mental state was "deteriorating" and it was time to begin hearings to study if he was emotionally and mentally capable of serving in office.

Here are the 9 most damning statements saying the president's mental stability is dangerous for the country.

1. Dr. John Gartner, co-founder of the Duty to Warn PAC

"He has no empathy or concern for anybody but himself and so he will not care about the destruction that it will cause other people. In fact, because of his sadism, there’s a part of him that perversely seems to revel in causing chaos and destruction and making us all frightened all the time, but even more importantly, it will be irresistible for him because it will transform him from feeling like a hunted victim of this witch hunt to feeling like an omnipotently destructive victor," said Dr. Gartner.

2. Dr. Bandy X. Lee, Yale University psychiatry professor.

“As a co-worker, [House Speaker Nancy Pelosi] has the right to have him submit to an involuntary evaluation, but she has not,” Dr. Lee said. “I am beginning to believe that a mental health hold, which we have tried to avoid, will become inevitable.”

“This is exactly the kind of dangerous event we foresaw as Donald Trump’s response to the impeachment proceedings, just as his pulling troops from northern Syria was a direct response to the announcement of an impeachment inquiry,” Lee said. “This was why more than 800 mental health professionals petitioned Congress to consult with us, since, without intervention, this kind of crisis was a matter of time, not just a possibility.”

3. `Dr. Howard Gardner, Harvard University professor

"If you are going to make statements about what it means to be intelligent, you need either to define intellect clearly, give the results of formal testing, or both. To my knowledge, Trump has done neither," he told the Washington Post.

"Second, however you define intellect, you need to distinguish between that cognitive capacity, and others arguably of equal or greater importance — for example, relevant knowledge, judgment, wisdom. And if you are addressing an individual’s potential to lead and to inspire, you need to take into account personal and temperamental capacities that are not, strictly speaking, cognitive or intellectual: for instance, patience, perseverance, empathy, forgiveness," he continued.

4. Psychiatrist Steve Wruble

“Donald Trump’s early development,” he writes, “created who we are witnessing. ... [H]is father’s intensity left its mark on the entire family. Donald’s oldest brother essentially killed himself under his father’s rule. This tragedy must have played a prominent role in the formation of Donald’s identity and left minimal room to rebel against his father’s authority, except through competition in the realm of business success. Despite their appreciation for each other, the tension between father and son caused Donald psychological wounds that still fester.”

5. Therapist Diane Jhueck

Jheck asked, rhetorically, Why Donald Trump’s “dangerousness” wasn't identified and dealt with early on in his life?

It was likely that the wealth and power of his family insulated him.

"His father had similar mental health disturbances,” lessening the possibility that the younger Trump’s behavioral problems would be addressed. She writes that Trump “exhibits extreme denial of any feedback that does not affirm his self-image and psychopathic tendencies, which affords him very limited ability to learn and effectively adjust to the requirements of the office of president. Rather, he consistently displays a revenge-oriented response to any such feedback.”

6. Lance Dodes, a retired psychiatry professor at Harvard Medical School

“The failure of normal empathy, is central to sociopathy, which is marked by an absence of guilt, intentional manipulation and controlling or even sadistically harming others for personal power or gratification.” In the book, he lists examples of Trump’s lack of empathy, “loss of reality” and “rage reactions and impulsivity," he wrote in The Dangerous Case of Donald Trump.

7. Stanford University professor emeritus Philip Zimbardo and Rosemary Sword,

The two wrote in a column for Psychology Today, that the president’s tweets where he brags about his intelligence are only part of his arrogance that point to reckless behavior that could put the country in greater danger.

"We were concerned that, given his 'straightforward' or 'outsider' presentation and charisma, he would appeal to people who were unaware of the dangers of his obvious narcissistic personality type, and the offensive behaviors that can accompany it. These behaviors include but are not limited to condescension, gross exaggeration (lying), bullying, jealousy, fragile self-esteem, lack of compassion, and viewing the world as Us-vs.-Them. Having observed the schoolyard-bully tactics Trump employed during public debates, as well as his boasting presentation during interviews, we felt it was important to raise awareness about his behaviors," they wrote.