This article is a literature search about the psychopathology related to hepatitis C and its treatment with interferon. An overview of the methodology of the available studies is presented. New theories for a better understanding and diagnosis of the psychiatric alteration associated to hepatitis C or interferon treatment are proposed, to improve future research. We discuss neurobiological aspects, clinical manifestations, psychosocial features and pharmacotherapy of the psychiatric manifestations of hepatitis C and its treatment with interferon.