Depressive Symptom Heterogeneity and Inflammation: The Moderating Role of Early-Life Trauma

Despite the high prevalence rates of depression, particularly among young adults, current treatments remain suboptimal, partly owing to the complex and heterogeneous nature of the disorder. While some individuals with depression display elevated inflammation, this is not consistently reported and may depend on the specific symptoms expressed. Moreover, individuals exposed to traumatic events may be more vulnerable to inflammation and mood disorders. In the current study young adults (N=210) completed baseline questionnaires assessing adverse early life experiences and depressive symptoms, provided blood samples to measure C-reactive protein (CRP) levels, and were assigned to either a control (n=106) or a stressor (n=104) task. CRP levels were positively correlated with both typical (p=0.02) and atypical depression (p=0.03), as well as total trauma (p=0.02), general trauma (p=0.012), and physical abuse (p=0.02) within the stress group. Notably, upon assessing specific symptoms of depression, somatic features including sleep and fatigue correlated with higher CRP levels. Additionally, the relationship between CRP levels and depressive symptoms was moderated by experiences of sexual abuse (p=0.03). These findings suggest that the CRP-depression link may be driven by somatic features of depression, and that exposure to early life trauma may play an important role in modulating this relationship. Understanding the relationship between adverse early life experiences, inflammation, and specific depressive symptoms can help inform an integrated approach that combines biological, psychological, and social factors to improve both prevention and treatment outcomes for depression.