This paper addresses the cultural authority of modern psychiatry in the late 1930s Lebanon. It introduces a new reading of the institutionalization of the feminist Nahda literary critic and translator May Ziade at the Lebanon Hospital for Mental Disorders, by exploring the biotechnologies and social lives of her diagnosis: Involutional Melancholia. The paper combines multiple forms of research based on the archival records of the Lebanon Hospital for Mental and Nervous Disorders, as well as research on the psychiatric genealogy of Involutional Melancholia within the history of psychiatry, and primary and secondary sources, including biographies and literary manuscripts. I trace the scientific-making of Involutional Melancholia between Europe and Lebanon, looking at the practices and diagnostics through which certain kinds of women in late 1930s Lebanon could “slip” into psychiatric institutionalization, becoming outside the margins of society. Ziade’s institutionalization led to a raging public debate over women, madness and mental illness, the echo of which still vividly resonates in literary and intellectual circles, among archivists, scholars and feminists today. By engaging the expertise of modern psychiatry with these debates, this paper approaches the clinical encounter as a site of knowledge-making that impacts cultural understandings of gender, mental illness and social pathologies, and delimits the promises of Arab modernity itself.