I have often heard it said how some people are a prisoner of their own mind (though I think neuroscience is slowly showing that the mind may not be a thing as that the functions previously attributed to it are just the brain itself).
Others have a more metaphysical take on it.
In Buddhism I know there is a saying about how the mind is great servant but a terrible master. I can attest to that since I often let my thoughts wander and craft stories or lines of logic that don’t make sense at all and sometimes how I truly feel about things tends to get buried in the “noise”. For others it might be being consumed by certain emotions or thought patterns and they can’t see clearly.