A Florida teenager has been convicted in a vicious kicking and stomping attack on a girl outside a middle school in 2010 by a jury that rejected his insanity defense.

The jury on Monday found 17-year-old Wayne Treacy guilty of attempted first-degree murder in the assault on then-15-year-old Josie Lou Ratley. Treacy could get up to 50 years in prison. Ratley has permanent brain injuries.

The crux of the case was Treacy's defense that he was not responsible because he suffered from severe post-traumatic stress disorder resulting from his brother's suicide a few months earlier.

The attack happened after Ratley enraged Treacy by sending him a taunting text message about his dead brother.

Experts agreed Treacy had PTSD. But prosecution psychiatrists testified that Treacy clearly knew right from wrong.