Background: Experiences of early life maltreatment (ELM) are alarmingly common and represent a risk factor for the development of psychopathology, particularly depression. Research has focused on alterations in autonomic nervous system (ANS) functioning as a mediator of negative mental health outcomes associated with ELM. Early alterations in autonomic vagal activity (vmHRV) may moderate the relationship between ELM and depression, particularly when considering forms of emotional maltreatment. Recent evidence suggests that the relationships of both ELM and vmHRV with depression may be non-linear, particularly considering females.Objective: Building on and extending theoretical considerations and previous work, the present work aims to further the current understanding of the complex relationships between ELM exposure, vmHRV, and depression.Methods: This study uses an adaptive modelling approach, combining exploratory network-based analyses with linear and quadratic moderation analyses, drawing on a large sample of males and females across adolescence (total N = 213; outpatient at-risk sample and healthy controls) and adulthood (total N = 85; community-based convenience sample).Results: Exploratory network-based analyses reveal that exposure to emotional abuse is particularly central within a network of ELM subtypes, depressive symptoms, and concurrent vmHRV in both adolescents and adults. In adults, emotional neglect shows strong associations with both emotional abuse and vmHRV and is highly central as a network node, which is not observed in adolescents. Moderator analyses reveal significant interactions between emotional maltreatment and vmHRV predicting depressive symptoms in adult females. Significant quadratic relationships of emotional maltreatment and vmHRV with depression are observed in both adolescent and adult females.Conclusions: The present findings contribute to the understanding of the psychological and physiological mechanisms by which ELM acts as a risk factor for the development of depression. Ultimately, this will contribute to the development of targeted and effective intervention strategies to mitigate the detrimental effects of early adversity.
Early exposure to chronic and severe adversity, which includes experiences of maltreatment, defined by the World Health Organization as physical, sexual, emotional abuse and/or neglect of children under the age of 18, is highly prevalent in the general population (estimated at 4050 percent), and is a well-documented risk factor for depression.The present work combines network-based analyses with tests of different functions (i.e. linear, nonlinear quadratic) in moderator analyses to further explore the complex relationships among ELM exposure, vmHRV, and depression.The present findings contribute to the understanding of the psychological and physiological mechanisms by which early exposure to chronic and severe maltreatment acts as a risk factor for the development of depression.Ultimately, this will contribute to the development of targeted and effective intervention strategies to mitigate the detrimental effects of early adversity.
Autonomic Nervous System , Depression , Humans , Adolescent , Adult , Female , Male , Emotional Abuse , Emotions , Outpatients
BACKGROUND: Depression is one of the most common mental disorders and a leading cause of disability worldwide. In adults, depression is characterized by decreased vagal activity (vagally-mediated heart rate variability; vmHRV), while vmHRV is inversely correlated with depressive symptoms. In children/adolescents, a 2016 synthesis (4 studies, 259 individuals) found similarly decreased vmHRV in clinical depression, but no significant association between depressive symptoms and vmHRV (6 studies, 2625 individuals). Given the small number of studies previously considered for synthesis and the rapidly growing evidence base in this area, a meta-analytic update was warranted. METHOD: A previous review was updated by a systematic literature search to identify studies that (a) compared vmHRV in clinically depressed children/adolescents with non-depressed controls and (b) reported associations between vmHRV and depression severity. RESULTS: The search update identified 5 additional studies for group comparison (k = 9 studies in total, n = 608 individuals in total) and 15 additional studies for correlational meta-analysis (k = 21 studies in total, n = 4224 individuals in total). Evidence was found for lower resting-state vmHRV in clinically depressed children/adolescents compared to healthy controls (SMD = -0.593, 95 % CI [-1.1760; -0.0101], I2 = 90.92 %) but not for a significant association between vmHRV and depressive symptoms (r = -0.053, 95 % CI [-0.118; 0.012], I2 = 65.77 %). Meta-regression revealed a significant association between depressive symptoms and vmHRV as a function of sex. LIMITATIONS: The samples considered are highly heterogeneous. Data on the longitudinal association between vmHRV and depression are currently lacking. CONCLUSION: The present findings support the use of vmHRV as a biomarker for clinical depression in children/adolescents.
