Does bipolar disorder differ from other mental illnesses in terms of emotion dysregulation? A systematic review and meta-analysis

IntroductionEmotion regulation (ER) is the ability to assess, monitor, or modify emotional reactions to achieve a goal (Gross. Psychological inquiry 2015; 26 1-26). When ER strategies are rigidly or maladaptively applied, emotional dysregulation (ED) can occur (Thompson. Development and psychopathology 2019; 31 805-815). ED is common in people diagnosed with bipolar disorder (BD), but it can also be described in other clinical populations given its transdiagnostic nature. Numerous aspects of ED have been described in BD (De Prisco et al. Neuroscience & Biobehavioral Reviews 2022; 104914), but it is unclear whether these manifest similarly in other conditions such as major depressive disorder (MDD) or borderline personality disorder (BPD), or whether they are specific to BD.ObjectivesThe objective of this systematic review and meta-analysis is to examine the literature comparing BD with other psychiatric disorders in terms of ED, focusing on those studies using validated clinical tools.MethodsA systematic search from inception to April 28th, 2022, was conducted exploring the PubMed/MEDLINE,EMBASE, Scopus, and PsycINFO databases. Those studies providing quantitative data on ED in people diagnosed with BD and compared with clinical groups were eligible for inclusion. No restriction about age, sample size, or language were applied. Random effect meta-analyses were conducted, and effect sizes were calculated as standardized mean differences (SMD).ResultsA total of 3,239 records was identified and, after duplicate removal and title/abstract evaluation, 112 were explored at the full text. Twenty-nine studies were finally included, and it was possible to perform a meta-analysis with twenty-two (145 comparisons) of them. Only studies comparing BD with MDD, and BPD provided sufficient data to perform a meta-analysis. People with BD did not differ from people with MDD in most of the comparisons considered. However, BD patients presented higher positive rumination (two comparisons: SMD=0.46; CI=0.27, 0.64; p=8.5e-07; I2=0%; and SMD=0.34; CI=0.15, 0.52; p=2.7e-04; I2=0%) and risk-taking behaviors (SMD=0.48; CI=0.27, 0.69; p=8.11e-06; I2=0%). In contrast, people with BPD displayed an overall higher degree of ED (SMD=-1.22; CI=-1.94, -0.5; p=9.1e-04; I2= 90.7) and used fewer adaptive ER strategies. Additionally, higher levels of self-blaming (SMD=-0.80; CI=-1.11, -0.50; p=2.68e-07; I2=0) and impulsive behavior (SMD=-0.76; CI=-0.89, -0.63; p=5.4e-29; I2=0) were observed.I