Editor’s Note: Michael D’Antonio is author of the book “Never Enough: Donald Trump and the Pursuit of Success” (St. Martin’s Press). The opinions expressed in this commentary are his. View more opinion articles on CNN.

CNN —  

You cannot go wrong by expecting the worst from Donald Trump.

Within 24 hours, he called on the attorney general to halt the investigation into his campaign’s links to Russia, slammed the criminal prosecution of his former campaign manager Paul Manafort as a “hoax,” and lied with great confidence at his Florida rally about his own popularity. Add his wacky claim that people need to present identification to buy groceries, and you get Trump at his worst.

Coming from any other President, Trump’s brand of crazy talk – much of it personal, ugly, and deranged – would be enough to prompt calls for the White House doctor, who would, at the very least, prescribe some rest. But with Trump, statements that sound like he’s trying to obstruct justice and distort reality no longer stir widespread outrage because he has taught the world to stop trying to make sense of what he says.

Eighteen months into his administration, Trump has bombarded us with so much awful noise that our minds have been trained to disregard much of it.

A good analogy from biology is what happens to people who work in foul environments and become desensitized to the odors. They just don’t notice the stench anymore. In psychology, this process has been observed when it comes to violence. Repeated exposures inure people to the suffering.

With Trump, it seems like the natural inclination for those who don’t agree with him is to defend themselves from the onslaught by abandoning the idea that the public will get anything approaching truth, dignity, and decency from our President.

We also try to tamp down the sense of fear we experience because our minds cannot handle the hits of adrenaline that come when Trump’s awful words and the mob-like reactions from his followers trigger our fight-or-flight response.

Many people can recognize the signs of danger in words or the shifting mood of a crowd. When CNN’s Jim Acosta recently warned of the potential for violence inspired by Trump’s rageful comments about journalists, he demonstrated a higher-order version of this instinct. Acosta tweeted a video of his encounter with Trump supporters at the President’s rally in Tampa, Florida and wrote, “We should not treat our fellow Americans this way. The press is not the enemy.”

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    If you watch the rally video Acosta posted, you will see the kind of rage one might expect to be directed at a mass murderer or an enemy proven to have plotted the absolute destruction of our society. Trump has incited this feeling by repeatedly calling reporters the “enemy” and offering lies about “fake news” to support this charge.

    In chip-off-the-block fashion, the President’s son, Eric Trump, took to Twitter to boost those who spewed venom at Acosta by appending the word “truth” to a clip of the chanting rallygoers, and the President retweeted Eric Trump’s tweet.

    Outside of the Trumposphere, the awful statements and sentiments of the President and his enablers are discounted by public officials – Paul Ryan is one example – who keep trying to do their jobs, and by everyday citizens who have become numb to his rhetoric. However, this numbness does not indicate that we are immune to the damaging effects of Trump’s destructive habits, any more than the effects of anesthesia eliminate the true impact a surgery can have on the body.

    With his continuing attacks on the justice system, the press, and reality itself, Trump makes it impossible for those outside his base of support – and, according to the recent approval ratings, most Americans fall outside of it – to recover a sense of equilibrium.

    This is the problem that we are talking about when, over coffee, we say the country no longer feels like the place we believed was exceptional. It is the problem that we try to address when we say “this is not normal,” and when we ask, “What has happened to us?”

    What has happened to us is Donald Trump. And this is not normal. While it may be natural to unplug once in a while, the persistent pain reminds us that the damage continues.