By Erika Angulo, Producer, NBC News
In classrooms across the country, teachers are going back to school to learn how to spot symptoms of mental illness among their students.
It's all part of an effort to prevent incidents such as this week's shooting at an elementary school in Georgia, which could have ended in disaster were it not for the quick thinking of school bookkeeper Antoinette Tuff. Suspect 20-year-old Michael Brandon Hill told Tuff he was mentally unstable and had nothing to live for, but she calmed him down, and convinced him to surrender.  
Mental illness also played a role in the December shooting deaths at Sandy Hook Elementary in Newton, Conn., and the massacre at Columbine High School in Colorado 14 years ago.
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