Difficulties in emotion regulation in bipolar disorder: A systematic review and meta-analysis

Background: Bipolar disorder (BD) is a severe mental disorder characterized by mood swings and functional impairment. Although alterations in emotional regulation (ER) are a key feature, a comprehensive meta-analysis on abnormalities in emotion regulation in BD is still lacking. Methods: We performed a random-effects meta-analysis on studies comparing the ER measured with the Difficulties in Emotion Regulation Scale (DERS) in BD and healthy controls (HC) or borderline personality disorder (BPD) and calculated the standardized mean difference (SMD) of the total DERS score between those with BD and HC (primary outcome). Secondary outcomes were the SMD of the DERS subscales between BD and HC, as well as the SMD of the total score of DERS and the subscales between BD and BPD. Results: Twelve studies (858 BD, 540 BPD, 285 HC) were included. Compared to HC, BD showed significantly higher total DERS score (k=8, SMD 0.962, p<0.001) and subscale scores, including non-acceptance (k=6, SMD=0.85, p<0.001), goal-directed behavior (k=6, SMD=0.894, p<0.001), impulse control (k=6, SMD=1.08, p<0.001), strategies (k=6, SMD=1.25, p<0.001) and emotional clarity (k=6, SMD=0.694, p=0.001). Relative to BPD, BD presented significantly lower scores in all the DERS subscales. Sensitivity analyses confirmed the main analyses. The age of the participants and sample size moderated the primary outcome. Limitations: The small number of studies and the cross-sectional design limit the generalizability of the results. Conclusions: Our findings suggest that alterations of specific ER abilities are present in BD and their magnitude is smaller relative to BPD. Future therapeutic interventions should target ER strategies.