So many of us thought Columbine was an aberration. We believed that after the post-mortem of the massive senseless shootings by two students attending that school, such madness would never recur.

How wrong we were. These heartbreaking tragedies haven't stopped. After 20 years, America should have found some real answers to preventing mayhem in schools. We need answers more than the usual thoughts and prayers.

School and university shootings are nothing new. What is new is their increased frequency and inevitable deaths. Historical reports show that there have always been isolated violence and deaths on school campuses.

These are documented by Wikipedia starting in the 1840s when a University of Virginia law student shot and killed his professor. In 1898, six people were shot and killed at a school exhibition in Charleston, West Virginia. Between 1900 and the 1950s, there were approximately 72 school shootings.

Seventeen school shootings occurred in the 1960s, including the first mass shooting in 1966 when a University of Texas student at the Austin campus first killed his mother and wife with a knife and then climbed the university's bell tower and killed 18 and wounded 31. Most people believed that this was just an isolated case of a very disturbed individual.

Something seemed to change in American society in the 1970s, when 30 school shooting incidents occurred. The two major campus shootings, Kent State (Ohio) and Jackson State (Mississippi) had political issues and were carried out by National Guard and police agencies. California State at Fullerton also experienced a mass shooting. In the 1980s, 41 school shooting incidents occurred; three had multiple victims.

There were more than 120 different school shootings from the 1990s through the 2000s. They happened across the nation in small and large communities. Columbine in 1999 was the most significant, but four others were major. In 2007, the Virginia Tech massacre took place; it left our nation bewildered and distraught. Again, we had thoughts and prayers, but no helpful answers.

From 2010 to the present, there have been 179 different school shootings. The most infamous were the 2012 Newtown (Sandy Hook, Connecticut) and 2018 Parkland (Florida) massacres. Yet, in 2018 there also were two other school shootings, each resulting in 10 deaths and many injured. We don't even remember the places of all of these terrible tragedies. What is wrong with us?

Many people believe that social media has been a game changer. While it may have some effect on those seeking revenge or publicity, it's too simple an explanation for American school deaths. Bullying, often linked to peer violence, is not new and most schools work to prevent it.

Mental health issues are clearly part of school violence. However, predicting who is going to shoot others is still more of an art than science. Guns have been around for ages and used to shoot people in schools for over a century. However, the guns of old were not set to kill multiple people quickly and easily, as do today's assault weapons, which do not need to be easily available to all. School violence explanations also include decreased family stability, frequent exposure to violence and drugs in media and life, and a youth culture unable to handle frustrations.

The data on shootings in educational settings show that such murders have occurred for generations, but they have increased dramatically during the past few decades. Americans still haven't found a way to curtail these tragedies. We know the questions that follow each of these horrible events. Twenty years after Columbine, America desperately needs answers.

Diane W. Mufson is a retired psychologist. Her email is