Sigmund Freud believed that children go through stages of psychosexual development. Freud proposed five psychosexual stages of personality development. In his model of the child's psychosexual development, Sigmund Freud describes five stages. Freud's theory of psychosexual development is represented amongst five stages. Wilhelm Stekel considered sado-masochistic practices to be variant behavior arising from psychosexual infantilism. This is the second stage of Freud's psychosexual stages. Freud believed in the libido, which he referred to as psychosexual energy. Psychiatrists were now able to diagnose psychosexual disorders in place of perversions. A medical, psychosexual and psychiatric history should be documented. He also proposed the concepts of psychosexual development and the Oedipus complex, among other theories. Published in 1928, Mead's ethnography focused on the psychosexual development of adolescents in Samoa. The film is a fantastical psychosexual retelling of life from Stewart's point of view. The anal stage is the second of five stages of psychosexual development. Consequently, the utility of rodent models for studying human psychosexual differentiation has been questioned. He seems to accept Ann's story, unconvinced by his own psychosexual explanations of her visions.