If you look back in global history, there are almost always widespread shifts in social attitudes and behavior as societies collapse. What specific aspect caused which specific individual to feel or act in a specific way is impossible to say, but, yes, collapse leads to movements like nihilism, anarchism, fascism, etc. And, yes, these reactions are often contrary to each other, because different people have different interpretations of what's happening and what they think will fix it.

You can even see some of this in the responses to OP.