Look to the causes of most gun violence, many recent events are reactions to problematic situations and could be prevented. Why does someone shoot up a school? What led them down that path, were they bullied, left out, ignored, repressed. Did they seek help, talk about their problems, become antisocial, etc? Was help offered/given, denied? Was the situation handled appropriately or allowed to continue unhindered? Was their actions a last resort to bring light to problems?
