Is mental illness a real factor for gun violence?
Yes. I think so
Mental illness is not the major reason of gun violence. According to researchers: It is usually cause by low self esteem and risky behaviour.
Both are part of it. Other reasons include:
Pop culture influence ( e.g violent movie scenes, violent games).
Decline in parenting and family values.
Parole, short sentencing, and early release of violent offenders.
Depression? Access to guns or what?
Yes, but on some occasions. Aside from that, there are many other reasons while people do gun violence.