The prevalence and predictors of bipolar and borderline personality disorders comorbidity: Systematic review and meta-analysis

Introduction: Data about the prevalence of borderline personality (BPD) and bipolar (BD) disorders co-morbidity are scarce and the boundaries remain controversial. We conducted a systematic review and meta-analysis investigating the prevalence of BPD in BD and BD in people with BPD.Methods: Two independent authors searched MEDLINE, Embase, PsycINFO and the Cochrane Library from inception till November 4, 2015. Articles reporting the prevalence of BPD and BD were included. A random effects meta-analysis and meta-regression were conducted.Results: Overall, 42 papers were included: 28 considering BPD in BD and 14 considering BD in BPD. The trim and fill adjusted analysis demonstrated the prevalence of BPD among 5273 people with BD (39.94 +/- 11.78 years, 44% males) was 21.6% (95% CI 17.0-27.1). Higher comorbid BPD in BD were noted in BD II participants (37.7%, 95% CI 21.9-56.6, studies = 6) and North American studies (26.2%, 95% CI 18.7-35.3, studies =11). Meta regression established that a higher percentage of males and higher mean age significantly (p < 0.05) predicted a lower prevalence of comorbid BPD in BD participants. The trim and fill adjusted prevalence of BD among 1814 people with BPD (32.22 +/- 7.35 years, 21.5% male) was 18.5% (95% CI 12.7-26.1).Limitations: Paucity of longitudinal/control group studies and accurate treatment records.Conclusions: BPD-BD comorbidity is common, with approximately one in five people experiencing a comorbid diagnosis. Based on current diagnostic constructs, and a critical interpretation of results, both qualitative and quantitative syntheses of the evidence prompt out the relevance of differences rather similarities between BD and BPD. (C) 2016 Elsevier B.V. All rights reserved.