Susan Nolen-Hoeksema (May 22, 1959 – January 2, 2013) was an influential American psychologist known for her work in the fields of women's mental health and emotion regulation. She was particularly recognized for her contributions to the understanding of how individuals cope with mood disorders and the concept of rumination—repetitive thinking about one's feelings and problems. Nolen-Hoeksema authored several academic articles and books, including the highly cited paper 'Responses to Depression and Their Effects on the Duration of Depressive Episodes,' which introduced the response styles theory. Her work has been instrumental in exploring the gender differences in depression and the social factors that contribute to the mental health of women. She served as a professor at Yale University until her untimely death in 2013 and left a lasting impact on the field of clinical psychology.