Agreement, Disagreement, and Life: Predicting Outcomes of Borderline Personality using Self and Informant Report

Abstract

Borderline Personality Disorder (BPD) impacts multiple functional life outcomes, but assessment may be difficult due to distortions in reports arising from the disorder itself. The use of adjunct informant reports shows promise in circumventing the barriers to self-report. Self and informant agreement has typically been low, but positive. I hypothesized this may be due to differences in perspective and available information. In this study, I used classic and novel statistical approaches to analyze agreement between self- and informant-reported BPD features in a community sample of individuals 55-64 years of age recruited as part of the St. Louis Personality and Aging Network. 1,387 participants were included in the final analyses. Optimal methods for combining self- and informant-report are explored in the prediction of clinically-relevant life outcomes. Self-reports and informant-reports were found to show limited, but positive, agreement in the endorsement of BPD criteria and diagnosis. Both reporters’ criteria endorsements were significantly associated with a similar number of relevant life outcomes, but had relatively low overlap (Mean overlap rate = 16%) in which outcomes were associated with any given criterion across both report types. These findings suggest that both self- and informant-reports provide incremental utility in the assessment of BPD features and appear to offer different information about those features.