The Hidden Patterns of BPD and NPD: A Deep Dive into Attachment and Interpersonal Dysfunction

This is a single-couple idiographic case study of the borderline/narcissistic type of relationships. Utilizing an integrated assessment approach that entailed the use of the Sacks Sentence Completion Test (SSCT) and the International Personality Disorder Examination (IPDE). The dyad was chosen purposely to investigate interpersonal complementarity in an intimate relationship. The borderline partner showed the abandonment-seeking patterns, which are manifested by the high SSCT relational conflict indices (M = 1.7), and the narcissistic partner showed the grandiosity-mediated withdrawal (M = 1.2). Thematic analysis brought out intertwining developmental formations typified by maternal deprivation and paternal wounding which helped create a sense of defensive complementarity in the dyad. The inter-coder reliability before consensus showed high agreement (Cohen’s κ = .82). The results shed light on the dyadic processes of personality pathology but are ideographically constrained and non-generalizable because the study was limited to a single couple. SSCT narratives were relational and attachment richer than those derived using structured diagnostics alone, which highlights that the combination of projective and diagnostic methods in personality assessment is indeed clinically valuable. Diverse dyadic constellation replication is justified.