A psychologist at Mesa State College says there are no easy answers to why an adult would walk into a school and kill children.
Dr. Susan Becker says such actions often bring copycat crimes and are not limited to school shootings but also include murder and other serious crimes.
Becker says people involved in school shootings are often victims of undiagnosed depression, and that can bring irrationality into an already dangerous mix. She says people with depression can easily let their emotions build up into irrational hate and a desire to kill, which she says is something others cannot understand.
Becker says when depression affects men the consequences are often worse because men hold in their feelings, abuse alcohol, and don't know where to turn for help, which can lead to violence.