Speaking of Meds, most of the shooters in Mass shooting had some type of mental illness. Most of the time, authorities say that the shooters was not taking his medication, however there are reports from family, friends and former co-workers who claim that they were taking Meds up to the time of the shooting. Authorities always check the blood to see what was in the person system and don't find what they are looking for the drug components that should be there and are not. A strong possibility is that they were take the drug that the doctor was prescribing them, but it was a new drug they gave them, not the official drug they needed. It was a kickback drug they the doctors got a profit from, in that it was not approved for. Another possibility is misdiagnosis.
There are also the fame seekers.
There needs to be a balance of gun regulation but there is none. It is easy to get a gun in the county, not just from the legal perspective, but from the black-market which will always thrive.