Forensic psychology and Firearms

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:

1. Pop culture influence ( e.g violent movie scenes, violent games).

2. Decline in parenting and family values.

3. Economic factors.

4. Parole, short sentencing, and early release of violent offenders.

5. Environmental factors.

Depression? Access to guns or what?

Yes, but on some occasions. Aside from that, there are many other reasons while people do gun violence.