Matt,

Everyone living in sin very likely has demonic activity in or around their
life.  True mentally ill people, on the other hand, don't fall into that
category, in my opinion.  However, some of the most positive people in the
world have demonic activity in their life and talk to demons all the time
without knowing it.  For example, I was listening to a world famous psychic
on the radio the other night.  I had never even heard of him.  People were
calling in and asking questions about what he believed.  The bottom line was
this, he said, man created God.  I said, wait just a minute.  The Bible said
God created man.  He said something else along those lines, reversing and
saying the opposite of the Bible.  In short, he was calling light darkness
and darkness he called light.  This man also told callers they could talk to
the dead and many other such things.  Also exactly the opposite of Biblical
instruction.  I have a friend who has what he calls a guardian angel but he
calls it that for my benefit because he knows what I believe it is.
Otherwise, he calls this presence in his life his spirit guide.  He refuses
to even once consider it is a demon spirit.  This, of course, has become
very common among new age philosophy.  When I was a Baptist, we thought all
Charismatics and Pentecostals were demon possessed.

Phil.