Principal diagnoses in psychiatric outpatients with borderline personality disorder: Implications for screening recommendations.

BACKGROUND: In the Rhode Island Methods to Improve Diagnostic Assessment and Services project, we examined how often borderline personality disorder (BPD) is the principal diagnosis in patients presenting for outpatient psychiatric treatment. To inform clinicians when it is most productive to screen for BPD, we examined the prevalence of BPD in psychiatric outpatients with different principal diagnoses.

METHODS: In this study, 3,674 psychiatric outpatients were evaluated with a semi-structured diagnostic interview for DSM-IV BPD.

RESULTS: Slightly ≥10% of the sample was diagnosed with BPD (n = 390, 10.6%). For 80 (20.5%) patients with BPD, the chief concern was related to a feature of BPD; therefore, BPD was designated as a comorbid diagnosis. The highest rate of BPD as a principal diagnosis was found among patients with bipolar disorder. The rate of BPD in patients with principal diagnoses of adjustment disorder, dysthymic disorder, and generalized anxiety disorder was significantly lower than in patients without these principal diagnoses.

CONCLUSIONS: For the majority of psychiatric outpatients with BPD, the principal diagnosis for which they seek treatment is not BPD but, rather, a mood or anxiety disorder. This highlights the importance of screening for BPD.