Jax, no one here is qualified to diagnose someone, much less someone we have never met, but as you have seen from the replies above, the behavior you describe could indicate either a mental or physical health problem.

If you would like to get an idea of what things these behaviors might describe, I would recommend going to the Home page here, and clicking on the link that says "What Is...?" It gives a list of symptoms for a variety of disorders. You might want to print out some of these to show to your wife, to give her an idea of how serious this behavior might be. One other thing, some of the conditions that these behaviors are consistent with are the paranoid and schizoaffective disorders, both of which tend to cause sufferers to resist treatment. Showing you wife this might also convince her that intervention is necessary in order to get help.

Good luck.
mj