PURPOSE: Receiving a diagnosis of schizophrenia can be a profound life transition that often has a negative influence on the patient's sense of self. The present study is the first to examine how self-defining memories are temporally distributed around age at diagnosis of schizophrenia. METHOD: 25 patients and 25 matched control participants identified 3 self-defining memories from their lives. In addition, participants were assessed with standardized interviews and questionnaires on negative and positive symptoms as well as tests of cognitive function. RESULTS: Patients' self-defining memories increased in the years leading up to diagnosis and declined abruptly in the years immediately following diagnosis. The pre-diagnosis increase in self-defining memories was not attributable primarily to a rise in disease-related recollections. CONCLUSION: The sharp post-diagnosis memory decline suggests that patients find it difficult to establish new or evolve existing definitions of self. Implications for models of schizophrenia and for clinical practice are discussed.