One example involves his recent meeting with German Chancellor Angela Merkel. Trump famously refused to shake her hand during her White House visit, the sort of rude treatment you'd reserve for someone with whom you're barely speaking. But then he bragged later in an interview about how he had "great chemistry" with Merkel.
So does Trump know he's lying when he says things like this or is he delusional?
"What we are witnessing is someone who needs to reshape reality to put himself in the center as 'the greatest' of whatever standard is being measured," the linked article notes. "He creates delusions to pretend he has accomplished great things."
If you've ever spent any time around someone who is psychotic, this is exactly the sort of behavior they exhibit. They make up preposterous stories and then believe them like they're verified facts.
The writer on the linked piece then asks: "the only remaining question about all of this is whether Trump actually believes these delusions or simply creates them in a calculated way."
She concludes Trump is delusional and not deliberately lying.
If she is correct, then the nation is in deep, deep trouble. We have a true lunatic in the White House.