I assume that the DOJ has psych consultants, or they can talk to Quantico (FBI psychologists). Safe to assume that there has been some discussion about Trump's mental status and how that would impact investigation and prosecution.
Early in my career I did forensic work as a mental health professional. Even county judges, detectives, chief of police would discuss the psychology of suspects with only minor infractions.
It is quite interesting and I assume we are not the first to discuss this topic. How abnormal psychology and the law intersect in the case of the People vs Trump.
Mental health professionals have been privately and publicly discussing Trump's mental status and future behavior for years. Actually some have been pleading that the public and officials listen to their warnings, to no avail.
Trump is quite dangerous, and refusal to listen to the warnings has been costly to the public and national security.
In terms of NGRI, Trump could argue he didn't know taking classified docs was wrong and he didn't cover it up.
1. Trump is sticking to his story that US government documents are his property.
If true, this sounds delusional. He sounds psychotic.
I guarantee you that there are psychologists who would testify that Trump is impaired.
He is delusional, exacerbated by his decades of amphetamine abuse (prescription meds, Adderall.)
I don't think he is psychotic, he is a ruthless sociopath. Being a sociopath with no moral core does not get you NGRI for sure. But he does at times to appear to be psychotic or delusional. And there would be mental health professionals who would testify to that.
2. He could further argue that he didn't cover anything up.
He moved the documents in full view as he left the WH. He moved them into MAL in full view. They were not hidden nor locked up in any way at the resort.
3. Trump's money shot on this issue that the FBI knew he had the documents for a long time and did nothing. So how bad could it be, and in doing so they were acknowledging his right to possession.
In terms of Trump not doing things because they won't work: I am sure there was someone who told him that trying to overturn the presidential election would not work, nor would trying to kidnap or kill Pence.
He did it anyway.
When a narcissistic sociopath is cornered they can really act out and get dangerous or act out of character. Yes I agree, his ego normally would get in the way of him pleading NGRI but if threatened with possible jail, he might pull a stunt of some sort. The DOJ would be very foolish to underestimate what Trump could do, what he is capable of.