Intensity and instability of affective and cognitive states in borderline personality disorder compared to remitted mood disorders and population-based controls: an Ecological Momentary Assessment study

Background Ecological Momentary Assessment (EMA) is one of the methods of choice for the evaluation of affective dynamics. Several studies have been conducted on the subject focusing on borderline personality disorder (BPD). However, most have only compared BPD to healthy controls. The present study aims to compare affective states, as well as an exploratory selection of cognitive, physiological, and psychomotor-activity states assessed by EMA of participants with BPD to those of participants with remitted bipolar disorder (BIP), remitted major depressive disorder (MDD), and population-based controls with no mood disorder, in terms of (1) intensity and (2) instability of these measures. Methods A total of 23 BPD participants, 18 participants with remitted MDD, 18 participants with remitted BIP and 269 participants from the general population (GP) were prompted four times a day during seven days to assess the intensity of the measured states. Linear mixed models were used to compare the BPD group with the three groups in terms of intensity (mean scores), whereas instability indices (within person variance; WPV and mean square successive difference; MSSD) were analyzed using generalized linear models with a Tweedie distribution and log link. In the framework of the generalized linear hypothesis testing, comparisons between the BPD group and the three groups were adjusted for multiple testing by single-step method. Results BPD participants were characterized by higher intensity and instability levels of sadness and anhedonia compared with participants with remitted MDD or BIP, as well as those from the general population. Higher intensity and instability in anxiety were also observed in the BPD group, although instability differences were less consistent across comparison groups. In addition, BPD participants reported higher instability in irritability and agitation relative to population-based controls. Conclusions Our results support the view that BPD patients display elevated intensity and instability of affects, including sadness, anxiety and anhedonia. Overall, the present study contributes to enhancing the understanding of affective dynamics in BPD through the application of EMA methodology. Clinical trial number Not applicable.