Groups the psychologists whose primary work concerns the assessment, diagnosis or treatment of mental illness and psychological distress, the largest single group among psychology's named figures. Belongs here: Sigmund Freud, Alfred Adler, Anna Freud, Carl Rogers, Aaron Beck, Melanie Klein, Donald Winnicott, Ronald Fairbairn, David Rosenhan, Albert Ellis, Karen Horney, Martin Seligman, Rollo May, Girindrasekhar Bose, Enrique Pichon-Riviere, Chabani Manganyi, Francis Cecil Sumner, Ernest Becker, Karen Machover, Molly Harrower, Martha Bernal and Nancy Chodorow. A figure whose primary contribution is a general theory of personality without a treatment or diagnostic focus is filed under personality psychology instead.