FORT LAUDERDALE, Florida (AP) - A South Florida teenager will serve 20 years in prison for a vicious kicking and stomping attack outside a middle school that left a 15-year-old girl with permanent brain injuries.

A Broward County judge imposed the sentence Monday on 18-year-old Wayne Treacy. He was convicted in July of attempted first-degree murder in the 2010 attack on Josie Lou Ratley outside Deerfield Beach Middle School.

Treacy unsuccessfully used an insanity defense, claiming he was suffering from post-traumatic stress disorder caused by the recent suicide of his older brother. The attack on Ratley came after the two of them exchanged a series of insulting text messages, including one about the dead brother.

Mental health experts agreed that Treacy suffers from mental illness, but prosecutors said he knew right from wrong.

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