The APA was pretty specific about it's objections to enhanced reporting requirements of New York's SAFE Act. And the inability to accurately predict individiuals who would commit gun violence was among their objections.
There are something near 17 million gun sales per year that go through the NICs background check, the number of sales/transfer that take place beyond that is unknown.
For the sake of argument lets say only 17 million gun sales would be connected to 'psychiatric evaluations', and let's ignore that there is no evaluation intended to determine if a person will commit gun violence at a future time. And lets just say, that evaluation could be made, meaningfully, in one visit.
In 52 weeks that would require an additional 327,000 psychiatric appointments to be met per week. Each evaluation takes not only an interview, but possibly personality test batteries, and interviews and test results would require evalution, and a written report, and then reporting to NICs or other national databse. All that effort These require time, time that can't be given to other patients...patients that are seeking help because they are ill, not merely jumping through a regulatory hoop. Such a "reform" in the psychiatric industry would add significant burden on the US psychiatric industry.
And what would such an evaluation really mean? Mental illness can strike at any age, even if incidence rates for many illness peak among people from 15-30 years of age. Some things, like depression, anxiety and adjustment disorders (things associated with 'going postal) have significant -social/environmental- components and it can't be known when if ever in a person's life sufficient contextual distress will occur
to result in psychological and behavioral dysfunction. Gun deaths from suicide among men, which have about an 80% association with mental illness increase with age.
Do we need gun permits that expires so that the person can be regularly re-evaluated, say annually? If so, that 17 million gun ownership related psych-exam number per year would quickly grow toward the -70 million legal gun owners in the nation needing exams. This sort of added effort within the American mental health industry wouldn't help it work better, it would move toward overwhelming it...or perhaps more likely...lead to the production of evaluations not worth the computer memory they are stored on.