Althusser became a tutor at the ENS. A Marxist, he influenced both Foucault and a number of other students, encouraging them to join the French Communist Party. Foucault did so in 1950, but never became particularly active in its activities, and never adopted an orthodox Marxist viewpoint, rejecting core Marxist tenets such as class struggle. He soon became dissatisfied with the bigotry that he experienced within the party's ranks; he personally faced homophobia and was appalled by the anti-semitism exhibited during the 1952–53 "Doctors' plot" in the Soviet Union. He left the Communist Party in 1953, but remained Althusser's friend and defender for the rest of his life. Although failing at the first attempt in 1950, he passed his agrégation in philosophy on the second try, in 1951. Excused from national service on medical grounds, he decided to start a doctorate at the Fondation Thiers in 1951, focusing on the philosophy of psychology, but he relinquished it after only one year in 1952. Foucault was also interested in psychology and he attended Daniel Lagache's lectures at the University of Paris, where he obtained a B.A. (licence) in psychology in 1949 and a Diploma in Psychopathology (Diplôme de psychopathologie) from the university's institute of psychology (now ) in June 1952. Early career (1951–1960) Over the following few years, Foucault embarked on a variety of research and teaching jobs. From 1951 to 1955, he worked as a psychology instructor at the ENS at Althusser's invitation. In Paris, he shared a flat with his brother, who was training to become a surgeon, but for three days in the week commuted to the northern town of Lille, teaching psychology at the Université de Lille from 1953 to 1954. Many of his students liked his lecturing style. Meanwhile, he continued working on his thesis, visiting the Bibliothèque Nationale every day to read the work of psychologists like Ivan Pavlov, Jean Piaget and Karl Jaspers. Undertaking research at the psychiatric institute of the Sainte-Anne Hospital, he became an unofficial intern, studying the relationship between doctor and patient and aiding experiments in the electroencephalographic laboratory. Foucault adopted many of the theories of the psychoanalyst Sigmund Freud, undertaking psychoanalytical interpretation of his dreams and making friends undergo Rorschach tests. Embracing the Parisian avant-garde, Foucault entered into a romantic relationship with the serialist composer Jean Barraqué. Together, they tried to produce their greatest work, heavily used recreational drugs and