Trump has what psychologists call the Dark Triad

[littlemissmartypants]

10. It's the result of brain damage/disorder from a variety of sources.

Could be stroke induced, could be caused by frontal/
prefrontal cortex lobe damage, or many different types of brain damage, like psychosis, Antisocial Personality Disorder, Bipolar disorder, any of the many schizo affective disorders, even head injury close and open types. It's also seen in dementia disorders.

And yes, it is suggested there in a hereditary component to many of the disorders mentioned especially Antisocial Personality Disorder but APD can be related to actual physical insult to the brain.

The most famous example of which is the story of Phineas Gage.

Phineas P. Gage (1823–1860) was an American railroad construction foreman remembered for his improbable[B1]:19 survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior over the remaining 12 years of his life‍—‌effects sufficiently profound (for a time at least) that friends saw him as "no longer Gage." [H]:14

https://en.wikipedia.org/wiki/Phineas_Gage



More here:
https://www.smithsonianmag.com/history/phineas-gage-neurosciences-most-famous-patient-11390067/

Anosognosia, also called "lack of insight," is a symptom of severe mental illness experienced by some that impairs a person's ability to understand and perceive his or her illness. It is the single largest reason why people with schizophrenia or bipolar disorder refuse medications or do not seek treatment.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.treatmentadvocacycenter.org/key-issues/anosognosia%23:~:text%3DAnosognosia%252C%2520also%2520called%2520%2522lack%2520of,or%2520do%2520not%2520seek%2520treatment.&ved=2ahUKEwjyzpyyoqXqAhWhdN8KHYgvDgUQFjABegQICxAI&usg=AOvVaw1rg1lTbABPfAKXkfhECAaB

Anosognosia is a result of changes to the brain. It's not just stubbornness or outright denial, which is a defense mechanism some people use when they receive a difficult diagnosis to cope with. In fact, anosognosia is central in conditions like schizophrenia or bipolar disorder.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.healthline.com/health/anosognosia&ved=2ahUKEwjyzpyyoqXqAhWhdN8KHYgvDgUQFjAHegQIDBAK&usg=AOvVaw1AceULMTbHJlB8C0Hm3pqu