And, nationwide, one of the big problems resulting in gun violence is the under-reporting or non-reporting of mental illness by mental health professionals and courts in states like Oregon where such reporting is required by law.  

CNN "As of October 2011, 23 states and the District of Columbia had submitted fewer than 100 mental health care records. Seventeen submitted fewer than 10 records, and four states hadn't reported a single record to the federal background check system, according to the federal investigation, conducted by the Government Accountability Office. 
As of October 2012, Oklahoma had submitted only three mental health records to the NICS Index, according to the mayors' group. 

20 states make most of the reports.
Texas reported 200,000 to the National Center.

I haven't been able to find where Oregon stands.  There are statutes requiring judges and the OSP to report, but I haven't been able to find out if they actually do.