Social decline

Note that although (post-)apocalyptic implies this, such settings should not be considered part of this by themselves. Apocalyptic fiction usually deals with the imminent destruction of the social order among other things but rarely actually deals with social decline/collapse as a result of it. In post-apocalyptic settings on the other hand, the social decline has already happened and is extremely likely actually the opposite of this, the raise of social order from the previous decline/collapse even if it still is noticeably worse than it was before the apocalypse.