Since the publication of Frantz Fanon's fuller body of work, a clearer picture has emerged of the correspondences between his clinical theories of subjectivity and his political theories of colonization. Yet no effort has been made to test these theories in an interpretation of the case histories Fanon compiled in ‘Colonial War and Mental Disorders,’ the last chapter of Wretched of the Earth, which documents the symptoms of colonial war and ethnic cleansing. This article closely reads one of Fanon's cases of ‘reactionary psychosis’ by speculatively reconstructing his engagement with Jacques Lacan's contemporaneous work on paranoid psychosis in the 1930s and early 1950s, particularly in his medical dissertation. Through the case interpretation, I offer a new approach to conceiving the unconscious dimension of colonization: the subject's forced occupation by the question of existence – ‘Who am I in reality?’