NICS doesn't get the data they want because....
What they want is your medical records to see if you were EVER on any anti depressants or other drugs which MIGHT point to a mental health problem.
HIPA .... prohibits health care professionals from discussing your medical records with anyone UNLESS you give your express written permission. This whole "information expansion " of NICS violates federal law, yet I have heard no mention of amending HIPA to make the new law legal.
It is another case of the government wanting to pick and choose what law they have to abide by.