The validity of psychiatric diagnoses has been at the heart of enduring and divisive debates in mental health discourse for over fifty years, often reaching a stalemate. Whilst some consider a diagnosis essential for validation and support, others view it as an obstacle to personal meaning-making. This chapter proposes that considering epistemic injustice may offer a valuable approach to overcome this impasse. By examining four facets of epistemic injustice—objectification, moral agency, trivialization, and narrative agency—it juxtaposes patient perspectives on borderline personality disorder and depression, arguably the least and most popular diagnoses with patients in psychiatry. Leveraging these four facets, it delves into the experiences of two representative patients, Cara and John, showing how epistemic injustice operates differently across diagnoses. This analysis suggests the importance of epistemic injustice as a tool in critically evaluating the usefulness of specific psychiatric diagnoses, enriching traditional metrics of reliability and validity in nosology. Moreover, it encourages a shift in clinical training to embrace reflective practices and restructure power dynamics in clinical encounters, promoting greater epistemic participation.