Guns don't kill people ....

[DanaC]

The thing is, if you ban anyone with any kind of mental illness, including depression and OCD, from owning guns, it increases the likelihood that some people suffering from such conditions will not seek help.

There is already a massive stigma attached to even run of the mill psychiatric conditions. The more aspects of life which are officially closed off from people on the grounds of mental health, the more mental health problems will go unreported and untreated. Some parents may even be inclined to not seek help for children they suspect of having some mental condition such as mild ADHD or depression, in order not to mark them out in a world which may well discriminate against them on that basis.