Taxometric analysis is a statistical methodology for testing between categorical and dimensional models of latent variables. This article reviews taxometric research on the structure of mental disorders conducted since previous reviews in 2003, a period in which the quantity of this work has more than doubled. Taxometric studies have addressed a wide variety of mental disorders whose status as discrete categories or dimensional continua has been controversial, including unipolar depression, schizophrenia subtypes, post-traumatic stress disorder, and attention deficit-hyperactivity disorder. They continue to yield categorical and dimensional findings with approximately equal frequency, and with adequate levels of replication. These findings are summarized, practical implications are discussed, and several concerns about current taxometric practice are raised.