Types of Insomnia. There are two types of insomnia: primary insomnia and secondary insomnia. 1  Primary insomnia: Primary insomnia means that a person is having sleep problems that are not directly associated with any other health condition or problem.
System of a Down's music has variously been termed alternative metal, nu metal, hard rock, progressive metal, thrash metal, art rock and avant-garde metal.
AllMusic Review by Johnny Loftus. It started in 2000 with Down with the Sickness.. Disturbed's thick, rhythmic take on alt-metal was perfect music for stalking bloody zombies, and vocalist David Draiman's jaw-snapping Pavlovian grunts made the trigger fingers of first-person shooters itch.