So, how did his pass the background firearm checks?
HIPPA. Health care workers can no longer report specific persons who wish to harm themselves or others to the police.
http://www.atf.gov/firearms/how-to/identify-prohibited-persons.html
“...who has been adjudicated as a mental defective or has been committed to any mental institution;”
Just seeing a shrink doesn’t lose one their rights. I suppose that will be changed now...
I believe you have to have been involuntarily commited or judged incompetent by a court.
He lied. There is no public record of his mental condition so there is no "fail safe" backup to lying on your ATF Form 4473 (filed with FFL licensed seller when transferring ownership of a firearm). That may change under Obamacare as all medical records will be computerized and accessible by authorized personnel (scary thought that, isn't it?).
Regards,
GtG