Except those disorders don't often translate to people acting terribly towards acquaintances. Sociopaths may be the nicest people you've ever met, if and when they want something from you. Schizophrenics may be various levels of detached from reality and perhaps difficult in that way, but only a tiny fraction of a percentage are so unhinged that they would act abusive or destructive.

There just isn't a large enough population of mentally ill with symptoms that would manifest as described to make up 5%, though they surely make up some part of it.