Ipseity at the intersection of Phenomenology, psychiatry and philosophy of mind: Are we talking about the same thing?

In recent years, phenomenologically informed philosophers, psychologists and psychiatrists have attempted to import philosophical notions associated with the self into the empirical study of pathological (self-)experience. In particular, so-called ipseity disturbances have been put forward as generative of symptoms of schizophrenia, and several attempts have been made to operationalize and measure kinds and degrees of ipseity disturbances in schizophrenia. However, we find that this work faces challenges caused by the fact that (a) the notion of ipseity is used ambiguously, both in the philosophical and in the empirical discussion, and (b) the methods employed to operationalize ipseity often portray a rather different understanding of the notion from that found in the (phenomenological) literature that is cited as providing the philosophical foundation for the studies in question. In particular, according to the definitions found in the philosophical literature, while being phenomenologically available, the self is not represented in ipseity. However, when it comes to the empirical study of ipseity and its disturbances, the object of investigation is often a kind of explicit self-representation. As a result, it is unclear whether different researchers are really talking about the same thing. Future progress in this area will require more careful conceptual distinctions; the present article aims to contribute to this task.