A patient describes, with obvious distress, that as he thinks something, people around him somehow know exactly what he is thinking at that moment — as though his thoughts are no longer confined to his own head and are somehow accessible to others. He denies that anyone is putting thoughts into his mind or taking them away. What is this?

This is thought broadcasting: the conviction that one's own thoughts are no longer private, and that others can somehow gain access to them, share them, or overhear them, as they occur. It is not thought insertion, which concerns foreign thoughts being placed into the mind from outside, not the patient's own thoughts becoming accessible to others; he explicitly denies this. It is not thought withdrawal, which concerns thoughts being actively removed, not shared outward. And it is not an auditory hallucination of thoughts spoken aloud (thought echo), which involves actually hearing a voice speak the thoughts, rather than a belief that others have silent access to them.