Phenomenological analyses of schizophrenia symptoms indicate that disturbances of self might be a core marker of the disease. It has been shown that alterations in the capacity to correctly distinguish between self-produced and other-produced actions pronounced in the symptoms (e.g. thought insertion) are detectable also in patients' performance in behavioral tests.
It is connected to diminished capacity of self-monitoring (e.g. of movements). It has been discussed whether Sense of Agency (SoA) is present only in patients with Schnieder's first-rank symptoms or it might be related to the disease itself, i.e. also in patients without them.