Yeah, I hope for your sake that you're trolling. When I was in high school and people still thought DXM was cool I had some friends that took 600-800mg daily for a few months and they certainly had brain damage. 600mg a day for years will certainly result in brain, liver and heart damage, and who knows what else.
That, and you'll be addicted to cough syrup. If you're actually consuming that much daily then there's probably a reason these "snitches" sent you to the hospital. They may actually care for your safety.
Be safe man.