And one of the other threats in the mental-health aspect:

They can change the definitions.  Expand them.
Biden called adjudication “a very high standard, basically being involuntarily committed to a mental institution.”

“We’re going to introduce legislation next week that says that if you are believed to be a risk to yourself or to others by your health care professional(no definition given, or standards), that that health care professional would have an obligation to report that fact to a police agency who then would initiate a process to — to make sure that you do not possess a firearm,” said the vice president’s son.

“You would have due process rights and you have a judicial proceeding(for now). But to make sure that those people who are mentally ill, that doctors believe shouldn’t be in possession of a weapon, don’t have them,” Biden continued. “Only 1300 people in 2010, for instance, were prohibited from possessing firearms because they were adjudicated mentally ill. This will broaden that category of people. We’ll have due process built into it. It will be constitutional and I think save lives, ultimately.”
Because we need LOTS of people banned from arms for this excus-ah, reason. Because it makes it so easy to disarm people, especially the way they'll decide things...

Apparently this crap runs in the Biden family.