REGULAR ARTICLE The Conceptual Tragedy in Studying Defense Mechanisms Dominik Stefan Mihalits 1,2 & Marco Codenotti 3 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract The concept of defense mechanism is interwoven with psychoanalytic theories of anxiety and psychic conflict. From its first formulation in 1894, its useful- ness resides in the degree to which it helps to explain otherwise mysterious phenomena. Statistical approaches to the study of defense mechanisms, which have significantly increased in popularity in the past three decades, test isolated assumptions without reflection on how these are integrated into psychoanalytic theory, nor on what should be regarded as psychoanalytic data. Consequently, their results and their models have not provided useful insights into psychoan- alytic theory. This paper aims to show how these issues in statistical approaches largely stem from disregarding discussions on the ontological status of defense mechanisms and the epistemological consequences linked to them. Studying defense mechanisms as they are manifested in external lifestyles, clouds the distinction between constructs (explanatory terms) and phenomena (empirical referents), which is furthermore necessary for a theoretical model to have explanatory value. Concrete examples are given regarding problems in statistical conceptualizations of defense mechanisms as well as the cursory explanations these tend to describe. Implications for future research are discussed. Keywords Psychoanalysis . Defense mechanism . Resistance . Psychoanalytic theory . Conceptualization . Statistics . Explanatory terms . Phenomena . Theoretical model Integr Psych Behav https://doi.org/10.1007/s12124-020-09515-6 * Dominik Stefan Mihalits dominik.mihalits@sfu.ac.at 1 Faculty of Psychology, Sigmund Freud University, Vienna, Austria 2 Institute for Lifespan Development, Family, and Culture, Department of Behavioural and Cognitive Sciences, University of Luxembourg, Esch-sur-Alzette, Luxembourg 3 Department of Psychology, Sigmund Freud University, Milan, Italy