here in New York fire starting out of anger, is the crime of arson.

in the old mental disorder diagnostics that will soon no longer be used, there was a mental disorder called pyromania but it was classified as an impulse control disorders not an anger disorder and was placed ie in the same category of mental disorders as obsessive compulsive disorder, kleptomania, pathological lying, gambling, drug addiction and other issues that have to do with a person showing uncontrollable /unconscious behavior patterns that were impulses not a conscious act.

As of the last I knew pyromania has been removed from the DSM 5 so its no longer considered a mental disorder here in the USA. thats not to say treatment providers wont be able to help who over has this problem. people with this problem can still get help for their pyromania issues, it will just be treated according to the underlying issue that is causing the person to start fires. example here where I live and work those that were labled "pyromania" thier psychiatrists are updating the diagnostics to the new diagnostics of removing pyromania and placing them under the terms "conduct disorder" and "intermittent explosive disorder" if anger issues apply.