Former Pittsburgh Steelers linebacker Anthony Chickillo was tased by cops at a hospital this week ... after police say he had a breakdown inside of a doctor's office.
According to the Hialeah Police Department, Chickillo was at the Hialeah Hospital in Hialeah, Fla. on Thursday morning ... when witnesses say he suddenly snapped and began "trashing" an office, breaking things and throwing chairs.
Cops say the former football player then allegedly "tried to attack everybody" -- before he got into a wrestling match with his dad.
Bystanders called 911 -- and when officers arrived on scene, we're told they deployed a taser in order to subdue him.