Emotional instability in borderline personality disorder: Specificity, determinants, and dynamic interplay with other symptoms.

Emotion dysregulation is considered a core problem of borderline personality disorder (BPD), which is a severe and pervasive mental disorder. Therefore, studies are investigating how emotions unfold in the daily lives of persons with BPD to better understand the dysfunction underlying BPD. Daily life studies found that persons with BPD typically show large changes in the intensity of their emotions and large changes between positive and negative emotional states, resulting in emotions that are highly unstable. Although this research linking BPD to patterns of emotional instability in daily life is important, the exact role of emotional instability in BPD remains unclear, both in terms of the specificity of findings after comparison with other disorders and the exact role it plays in BPD itself. We propose a project that allows us to fill these gaps. We want to examine (1) whether emotional instability is specific to BPD or is a feature of several mental disorders, (2) whether emotional instability is specific to only a certain subgroup of persons with BPD, or is a universal characteristic of BPD, (3) what drives emotional instability in BPD, by focusing on different processes underlying emotional change over time, and (4) exactly what role emotional instability plays in relation to other BPD symptoms, most importantly whether it follows from, or precipitates other symptoms. Findings will help to better understand what drives BPD, in order to improve treatment and prevention.