Last I checked, physicians must treat both symptoms and diseases simultaneously. E.g., the Shock. The bleeding. The excess fever.
Similarly there's no reason both cannot be tackled simultaneously here as well; for the root cause is often far more difficult to address than treating symptoms.
So yes, address the root causes such as:
Reducing societal stress (reduce work weak, lower socioeconomic inequality)
Expand and improve baseline education levels
Provide Universal healthcare with free access to mental health including therapy.
... But also address the symptoms, which means that when someone does inevitably fall through the cracks, they're not given free and easy access to gun that is lethally more effective than a knife.