Clinicians are encouraged to collect feedback from patients through ongoing, patient-report questionnaires to monitor treatment response and assess change. These instruments rely on a patient's self-reporting functional impairment, distress, and corresponding changes. This presents particular challenges when working with individuals diagnosed with a personality disorder due to the nature of their psychopathology. A pragmatic solution is for the clinician to notice certain affective, defensive, and cognitive markers, which can serve as observable indicators of emerging change in the patient's personality organization. I identify three markers: signal anxiety; repression; and mentalization. This proposition is illustrated by clinical material from the case of an adult patient diagnosed with borderline personality disorder and treated using psychoanalytic psychotherapy. Excerpts from a psychotherapy session are analyzed, providing a qualitative description and evaluation of change in the personality organization of a borderline patient, and highlighting the feasibility of assessing change in a real-world psychotherapy context.