The Ohio police officer who shot and killed a crazed gunman at a Damageplan concert 10 years ago has quit the force and is in counselling due to the emotional toll following his heroics.

James Niggemeyer was diagnosed with post-traumatic stress disorder and severe anxiety following the incident at the Alrosa Villa nightclub in Columbus, which cost guitarist 'Dimebag' Darrell Abbott his life in December, 2004.

Speaking to the Columbus Dispatch newspaper on the anniversary of the shoot-out (08Dec14), he says, "I found out real quickly that you don't have any control over your brain. It's going to do what it's going to do.

"Cops are regular human beings. Things affect us the same way they affect everyday citizens. We relive it and have to deal with the aftermath."

Niggemeyer, 41, adds, "The shooting changed my career path - not for the better, certainly. I'm happy to have been able to end the situation with no further tragedies after I arrived, but it certainly hasn't made my life any better."

The hero cop was patrolling blocks away when the call came in about the gunman at the club. He entered the Alrosa Villa via a back door and immediately saw the shooter and bodies on the floor. He was able to get off one shot, which killed the gunman instantly.