Not good.
I dunno, maybe a checkbox for psychotropic meds. Worth discussing that, methinks. Also reports from doctors who prescribe, and an admonition from the doctor to the patient, “if I prescribe this med, one of the side effects is possible suicidal or homicidal thoughts, so I am obliged to report this prescription to NICS. If you take this prescription, you agree to relinquish your right to keep and bear arms.”
And no gun-seller should be required to sell a gun to anyone they have reservations about.
I understand that it's a slippery slope, but there are two options: measures which infringe on Unalienable Rights, and measures which don't infringe on them. As gun owner's, we're duty bound to seek out the latter, or else the propagandists will ensure the former.
Having said that, it's also incumbent on gun rights advocates to staunchly and articulately defend those rights, and to repudiate the emotional, "feel good" measures which the Leftists propose—measures which both infringe on Unalienable Rights and are also ineffective.