OCD is most definitely an illness caused (at least in part) by a
malfunction in certain areas of the brain. This has been backed
up by extensive study of patients with OCD. Essentially our
brains malfunction in two key ways. First the filter between our
conscious mind and unconscious mind is broken. Thoughts occur in
the unconscious mind outside the control of the conscious mind,
that is true for all people. Random thoughts happen all the
time. In the minds of most people these thoughts are filtered
such that one seldom even notices the unpleasant ones. In those
with OCD the filtering is less effective. Second, our brains get
stuck in anxiety mode when these thoughts reach our conscious
mind, thus causing the obsessive anxiety to occur. The thoughts
are real in the sense that they occur. But in the sense that
they represent our actual desires and wants, they are not.
Having a thought pop in to your head does not mean you choose
that thought. Our brains are constantly processing sensory data
and trying to inte