A patient describes an unsettling change in the privacy of his thoughts, but you are not yet sure whether this is thought insertion or thought broadcasting. Before revealing the answer, decide what single question separates the two.

Ask which direction the disturbance runs: is something coming into the patient's mind from outside, or is something private leaving the patient's mind and becoming accessible to others? Thought insertion concerns an outside agency placing foreign thoughts into the person's own mind. Thought broadcasting concerns the reverse — the person's own private thoughts are no longer confined to themselves, whether experienced as escaping, being shared, or being made audible to others. Both are experiences of thought alienation and can occur together in the same patient, but the direction of travel of the thought is what tells them apart.