Given the international data (Yes, this problem happens in places other than the US and with weapons other than guns sometimes), most of these folks WHERE on SSRI drugs or had recently come off of them. The attempt to say that it is a mental health issue is a direct attempt to abuse the law as it currently stands in many states and with certain federal law (the legality of those laws is another can of worms that I am NOT touching on).
In many states and under parts of the USC, if you are declared a threat to yourself by a court under the advisement of doctor who has done an exam and testing of the person; you can be barred from owning firearms. The way these laws were written lends them to abuse and this is not the first time they have been abused. Also they can try to have a person evaluated without their consent (it gets much more ugly from there). The fun part is that the research that Obama directed the CDC to do is finished and been published (don't have a link at the moment and this is a quick message). The results basically say that gun owners are in the majority more sane and responsible than non gun owners. The document is a real interesting read. Now Obama is calling for a new study and is giving this study to a far left group that is outside the government to remove political bias.
The law is seriously flawed and the first legal challenge to it was to narrow in the focus of how it is unconstitutional. Anyway, yes it is tied to gun control and yes it is a violation of 2A (My opinion and I will defend it). -Michael