What makes someone crazy?

For everything that happens, there is reason to cause the event. A person usually goes crazy because of genetic and environmental factors. Those factors may cause some neurological disorder that leads to craziness.

apart from genetic and mental illness there is also sociatal factors. i think that at some point we all have the capacity to have some kind of psychotic break brought on by stress and untenable situations. normally rational people too can be pushed to the brink of insanity. then it will take that one little thing to push them over. basically then they seperate from reality. kinda like michael douglas' character in the movie falling down.

Genetic or clinical causes are not tied to particular triggers. No reason at all is necessary; it's basically a chemical thing.