Objectives:
This article addresses the problem of explaining emotional pathology (levels of personality organization) using the concepts of theory of mind (ToM) and mentalization. Although these terms are used interchangeably to describe the “ability to interpret the behavior of others in terms of mental states,” they do not have identical status in emotional disorders. ToM refers to a “cold” knowledge, whereas mentalization requires the activation of relational and emotional representations, as well as processing of emotional experience (whether reflection or defense). The aim of the study was to compare the cognitive (ToM) and affective (mentalization) aspects of “understanding the behavior of others in terms of mental states” in the clinical group—consisting of patients with borderline personality organization (N = 30)—and the control group (N = 30).

Methods:
The Borderline Personality Inventory was used as a diagnostic questionnaire for the organization of personality, the Strange Stories Test was employed to measure ToM, and the Mental States Task instrument measured mentalization.

Results:
With respect to mentalization, different patterns of results were obtained: the activation of overwhelming mental states and primitive defenses in the clinical group; and the inhibition of the recognition of mental content by defenses, such as denial and suppression of emotions, in the control group. No differences were observed in ToM between groups.

Conclusions:
In explaining the personality organization levels, only the affective, and not the cognitive, aspects of “understanding the behavior of others in terms of mental states” are significant.