They may be going through pharmacy records and checking against gun permits.
The Affordable Care Act will consolidate all medical records in a digital repository. It will be a simple name/SSN cross reference to find out who has been prescribed ooga-booga drugs. Look for all sorts of unintended (intended on their part) consequences....
High blood pressure medicine,
Ritalin and equivalents,
Sleep disorder medicines,
Weight loss medicines,
a whole host of disqualifiers.