Although repetitive thought (RT) styles such as worry, rumination, and processing correlate positively, they have divergent effects on well-being, suggesting important dimensional variation. In Study 1, multidimensional scaling identified 2 dimensions--positive versus negative content valence and searching versus solving purpose--among students (N=978) who completed standard RT measures. In Study 2, students (N=100) sorted 25 descriptions of RT. Multidimensional scaling identified 4 dimensions, including valence and purpose. Content valence associated with valenced affect; solving associated with less aroused affect and less polarized appraisals of thought topics. In Study 3, valence and purpose of RT descriptions by women in a breast cancer prevention trial (N=62) predicted concurrent affect and psychological and physical well-being.