Table 3. Main articles linking peripheral inflammation with emotion regulation, emotion reactivity or associated behaviours in bipolar disorder, borderline personality disorder, and attention deficit/hyperactivity disorder patients.
| Diagnosis | Main Findings | Sample | Measure(s) of ED or associated behaviours | Measure(s) of inflammation | Study type | Covariates | Directionality of the findings | |
|---|---|---|---|---|---|---|---|---|
| Dargél et al., 2017 [214] | BD | Peripheral levels of hsCRP were higher in patients with emotional hyper-reactivity and hypo-reactivity compared with patients showing normal emotional reactivity | 613 remitted BD patients; mean age = 41.2, SD = 12.4 | Multidimensional Assessment of Thymic States | Peripheral hsCRP | Cross-sectional | Age, sex, years of education, age at BD onset, BD subtype, total number of mood episodes (manic and depressive), suicide attempts, depressive symptoms, anxiety symptoms, manic symptoms, medications (antidepressants and benzodiazepines) | Positive correlation between hsCRP levels and alterations in emotional reactivity (hypo- or hyper-reactivity) |
| Dargél et al., 2020 [103] | BD | A data-driven allostatic load index including peripheral measures of inflammation (hsCRP and albumin) could predict with an 81.1% the presence of either hyper-emotional reactivity or non-hyper emotional reactivity in a cohort of BD patients | 1072 BD patients with non-hyper emotional reactivity (n = 528) or hyper-emotional reactivity; (n = 544); mean age of non-hyper reactive patients = 42.05, SD = 12.67; mean age of hyper reactive patients = 41.45, SD = 12.82 | Multidimensional Assessment of Thymic States | BALLI index for allostatic load including peripheral measures of inflammation (hsCRP and albumin), cardiovascular risk (systolic and diastolic blood pressure), glucose metabolism (glucose fasting), and lipid metabolism (triglycerides) | Cross-sectional | Age, sex, and smoking controlled for when assessing the allostatic load scores of patients with hyper-emotional reactivity and non-hyper emotional reactivity. | Emotional hyper-reactivity correlates with higher scores on the allostatic load; the BALLI index could predict with an accuracy of 81.1% patients with hyper-emotional reactivity |
| Saccaro et al., 2023* [250] | BD | Overall, structural and functional correlates of inflammation in bipolar disorder revealed a link between brain abnormalities and peripheral inflammatory markers in BD patients | Final number of studies = 23 (functional MRI = 6, structural MRI = 16, botch functional and structural MRI = 1) | MRI and functional MRI | Peripheral inflammatory mediators (depending on the study) | Systematic review | Most of the studies accounted for potential confounding factor (e.g., age, sex, treatments, and medical comorbidities) | Heterogeneous results, broadly supporting a positive link between peripheral inflammation and brain alterations in areas involved in somatomotor processing and affective processing |
| Westling et al., 2011 [403] | BPD | Increase in IL-1β levels in response to glucose was significantly greater in patients than in controls. Furthermore, IL-1β reactivity was associated with symptoms of hostility | 13 young women with BPD and 13 healthy young women as controls matched for age and BMI range; age range = 19–24 | Aggression Questionnaire Revised Swedish Version | Peripheral IL-1β, TNF-α, and IL-6 | Cross-sectional | Age and BMI | Positive correlation between IL-1β levels and glucose intake during a 5h glucose challenge (higher in BPD patients than controls). Additional positive correlation between IL-1β reactivity and symptoms of hostility |
| Yang et al., 2020 [329] | ADHD | Higher peripheral CRP levels were associated with more severe ED, including the total ER scale and the strategies subscale | 105 adult ADHD patients and 57 healthy adults as controls; median age of ADHD patients = 36 (age range = 29–43), median age of controls = 38 (age range = 34–43) | DERS-16 | Peripheral CRP, SAA, sICAM-1 and sVCAM-1 | Cross-sectional | Age, sex, BMI, ADHD medication, and other medications | Positive correlation between ED and CRP levels, no correlation between ED and SAA, sICAM-1 and sVCAM-1 levels |
| Skott et al., 2020 [356] | ADHD | The administration of a synbiotic for nine weeks improved ER in the subgroup of adults with high baseline sVCAM-1 levels | 114 adult ADHD patients, 57 receiving the synbiotic and 57 receiving the placebo; median age = 36 (age range = 29–42) | DERS-16 | Peripheral SAA, sICAM-1, and sVCAM-1 | Experimental | Age and sex | No effect of the synbiotic on DERS score after stratification for medication status. Positive effect of the synbiotic on DERS score in the subgroup of patients with high sVCAM-1 baseline levels |
Studies marked with ‘*’ are reviews. Abbreviations: ADHD, attention deficit/hyperactivity disorder; BALLI, allostatic load index for BD; BD, bipolar disorder; BMI, body mass index; BPD, borderline personality disorder; CRP, C-reactive protein; DERS-16, difficulty in emotion regulation scale-16; ED, emotion dysregulation; ER, emotion regulation; hsCRP, high-sensitivity C-reactive protein; IL-1β/-6, interleukin-1β/6; SAA, serum amyloid A; SD, standard deviation; sICAM-1, soluble intercellular adhesion molecule 1; sVCAM-1, soluble vascular adhesion molecule 1; TNF-α, tumor necrosis factor-α.