This chapter discusses the major psychological perspectives on mental illness. In terms of the biopsychosocial model, the unique contribution of psychology lies in its attention to the intra individual mechanisms that produce abnormal thoughts, feelings, and behaviors. Although there are a number of popular psychological models of abnormality, the chapter focuses on four: the psychoanalytic, cognitive behavioral, humanistic-existential-phenomenological, and the family systems approaches. Many psychodynamic theorists today are particularly interested in the mental representations that people have of themselves and others. Several theories of schizophrenia, propose that the disorder is most likely to occur in families in which messages are consistently disguised, contradictory, or accompanied by strong criticism. In family therapy, the therapist attempts to establish a healthy equilibrium within the family. Studies show that this kind of therapy is often effective for reducing conflicts and resolving specific problems such as bulimia.