This book examines sex and gender differences in the causes and expression of medical conditions, including mental health disorders. Sex differences are variations attributable to individual reproductive organs and the XX or XY chromosomal complement. Gender differences are variations that result from biological sex as well as individual self-representation which include psychological, behavioural, and social consequences of an individual’s perceived gender. Gender is still a neglected field in psychopathology, and gender differences is often incorrectly used as a synonym of sex differences. A reconsideration of the definition of gender, as the term that subsumes masculinity and femininity, could shed some light on this misperception and could have an effect in the study of health and disease. This second edition of Psychopathology clarifies the anthropological, cultural and social aspects of gender and their impact on mental health disorders. It focuses ongender perspective as a paradigm not only in psychopathology but also in mental health disorders. As such it promotes open mindedness in the definition and perception of symptoms, as well as assumptions about those symptoms, and raises awareness of mental health.