ATLANTA August 12, (Reuters)-- A judge Wednesday ordered a 15-year-old schoolboy to stand trial as an adult for allegedly wounding six classmates in a Georgia high school shooting rampage, rejecting defense claims the boy was mentally ill.

If convicted in adult court, T.J. Solomon faces more than 100 years in prison instead of the maximum five years he could have gotten in the juvenile system for allegedly bringing his stepfather's guns to school and shooting his classmates, all of whom survived.

Solomon showed no emotion when the judge announced his decision but the youth's mother, Mae Dean Daniele, slumped to her courtroom seat as the judge spoke.

Solomon is charged with 21 counts of aggravated assault, child cruelty and weapons possession in the May 20 shootings at Heritage High School in Conyers, Georgia, about 25 miles east of Atlanta.

Evidence and three days of testimony at his status hearing suggested that Solomon was copying the deadliest-ever U.S. school shooting incident in which 15 people, including two gunmen, were killed one month earlier in Littleton, Colorado.

More than a dozen other school shootings over the past six years have horrified U.S. communities, and Rockdale County District Attorney Richard Read said Conyers, a largely rural town of about 25,000, was no exception.

"The bullets were not only fired at our children, but in the collective hearts and souls of our community," Read said. "It made every parent and every teacher extremely afraid and extremely desperate for those we expect to protect the most in our society."

Defense attorney Ed Garland asked Judge William Schneider to try the accused as a child because the juvenile justice system in Georgia would have provided psychiatric care for him. The defense claimed that the boy was mentally ill.

"He is a sick boy," Garland said. "I suggest you use all the resources of the state to help this boy. If he goes untreated, you may probably find one day that he will have killed himself. You may find him hanging in a prison cell."

Schneider was not moved.

"There is no doubt that the child suffers and has suffered from emotional problems, but the statute on mental health requires more," the judge said. "It requires detachment from reality."

Georgia law stipulates that anyone under age 17 is a juvenile, but the judge said Solomon should be tried as an adult because of the seriousness of his crimes.

"The severity and the viciousness of these offenses makes it paramount to the public interest that he be treated not as a juvenile but as an adult," the judge said.

"The fact that the child attempted to copy a heinous and devastating crime through premeditation and deceit shows an even more outrageous disregard for our community," he said.

"The child wounded six high school students during a time in our history when these crimes have seen widespread publicity for the fear and horror, the alarm and shock that pervades the minds of parents and community members in our nation," Schneider said.

Students returned to Heritage High School Wednesday for the start of a new school year. Security was high, with Rockdale County police turning back cars that did not need to be in the area around the school.