Documented Borderline Personality Disorder and EMR Indicators of Potential Under-Recognition in Depressive Outpatients.

Background and Objectives: This study aimed to estimate the prevalence of documented borderline personality disorder (BPD) diagnosis and study-defined BPD indicators among adults with depressive disorders in outpatient psychiatric care, and to quantify a subgroup who were indicator-positive but had no documented diagnosis (potential under-recognition). Materials and Methods: This retrospective, cross-sectional study included adult outpatients with depressive disorders receiving pharmacological treatment at Maharaj Nakorn Chiang Mai Hospital. BPD status was classified using (1) a documented BPD diagnosis in the electronic medical record (EMR) and (2) study-defined indicators, comprising a symptom-based indicator (documentation of ≥5 DSM-5 BPD criteria) and a prescribing-based indicator (antidepressant treatment with concurrent use of antipsychotics and/or mood stabilizers). Prevalence and overlap across diagnoses and indicators were summarized using a Venn distribution. Results: Among 1175 patients, 63 (5.4%) had a documented BPD diagnosis. Using EMR indicators, 84 (7.1%) met the symptom-based indicator and 325 (27.7%) met the prescribing-based indicator. In total, 374 (31.8%) had either a documented BPD diagnosis or at least one indicator, while 801 (68.2%) had neither. Overall, 370 (31.5%) met at least one indicator (symptom-based and/or prescribing-based). Among indicator-positive patients, 311 (84.1%) had no documented BPD diagnosis, representing 26.5% (311/1175) of the total cohort. Conclusions: Study-defined EMR indicators flagged a substantial subgroup with potential under-recognition of BPD features in depressive-disorder clinics. These indicators may help prioritize targeted assessment and structured diagnostic evaluation to support access to BPD-informed care and support referral to BPD-informed psychotherapy.