Differential association of somatic and cognitive symptoms of depression and anxiety with inflammation: Findings from the Netherlands Study of Depression and Anxiety (NESDA)

Objective: Depression and anxiety have been suggested to be associated with systemic inflammation upregulation. However, results are not always consistent, which may be due to symptom heterogeneity of depression and anxiety. There are some indications that associations with inflammation are mainly driven by somatic symptoms of depression and anxiety. We therefore set out to evaluate the differential association of somatic and cognitive symptoms of depression and anxiety with inflammation, while adjusting for demographic, health related, and lifestyle related variables. Methods: We evaluated baseline data from 2861 participants from the Netherlands Study of Depression and Anxiety (NESDA). The Inventory of Depressive Symptomatology and the Beck Anxiety Inventory were used to assess depressive symptoms and anxiety symptoms. For both scales somatic and cognitive symptoms scales were calculated. Baseline blood samples were collected to determine high sensitivity C-Reactive Protein (CRP), interleukin (IL)-6, and Tumor Necrosis Factor (TNF)-α. We used linear regression to analyze the associations adjusting for demographics and health indicators and markers for an unhealthy lifestyle. Results: After adjustment for sociodemographic and health indicators, depressive symptoms were associated with higher levels of CRP, IL-6 and TNF-α. This association was mainly driven by somatic symptoms. For anxiety, somatic symptoms were associated with higher levels of CRP, IL-6 and TNF-α, whereas cognitive anxiety symptoms were associated with CRP (men only). Markers of an unhealthy lifestyle explained the significant associations. Conclusions: Especially somatic symptoms of depression and anxiety are associated with inflammation. However, this association was mostly mediated through unhealthy lifestyles among depressed and anxious individuals. © 2013 Elsevier Ltd

Association between exposure to HSV1 and cognitive functioning in a general population of adolescents: The TRAILS study

Background Infections with different herpes viruses have been associated with cognitive functioning in psychiatric patients and healthy adults. The aim of this study was to find out whether antibodies to different herpes viruses are prospectively associated with cognitive functioning in a general adolescent population. Methods This study was performed in TRAILS, a large prospective general population cohort (N = 1084, 54% female, mean age 16.2 years (SD 0.6)). At age 16, immunoglobulin G antibodies against HSV1, HSV2, CMV and EBV were measured next to high sensitive C-Reactive Protein (hsCRP). Two years later, immediate memory and executive functioning were assessed using the 15 words task and the self ordered pointing task. Multiple linear regression analysis with bootstrapping was performed to study the association between viral infections and cognitive function, adjusting for gender, socioeconomic status, ethnicity, and cannabis use. Results Presence of HSV1 antibodies was associated with memory function ((B = −0.272, 95% CI = −0.556 to −0.016, p = 0.047)), while the association with executive functioning did not reach statistical significance (B = 0.560, 95% CI is −0.053 to 1.184, p = 0.075). The level of HSV1 antibodies was associated with both memory function (B = −0.160, 95% CI = −0.280 to −0.039, p = 0.014) and executive functioning (B = 0.296, 95% CI = 0.011 to 0.578, p = 0.046). Other herpes viruses and hsCRP were not associated with cognitive functioning. Conclusions Both presence and level of HSV1 antibodies are prospectively associated with reduced cognitive performance in a large cohort of adolescents

Does tryptophan degradation along the kynurenine pathway mediate the association between pro-inflammatory immune activity and depressive symptoms?

Background Several studies have suggested that induced tryptophan (TRP) degradation through the kynurenine (KYN) pathway by the enzyme indoleamine 2,3-dioxygenase (IDO) is implicated in the relation between depression and inflammation. We investigated the role of tryptophan degradation in the relationship between inflammatory markers and depressive symptoms in the Netherlands Study of Depression and Anxiety (NESDA) and hypothesized that tryptophan degradation would mediate (part of) this association. Methods 2812 Participants of NESDA were included in this study including 1042 persons with current major depressive disorder (MDD). Assessments of C-reactive protein (CRP), interleukin (IL)-6, tumor-necrosis factor (TNF)-α, KYN and TRP were obtained from fasting blood samples at the baseline assessment. Tryptophan degradation was estimated by calculating the ratio [KYN/TRP]. Depressive symptoms were measured with the Inventory of Depressive Symptomatology. Results Significant associations between inflammation and depressive symptoms were found for CRP and IL-6, for the total group and the subgroup of patients with current MDD. Adjustment for KYN/TRP did not attenuate these associations. There were no significant indirect effects for CRP on depressive symptoms mediated by KYN/TRP for the whole group (B = −0.032; 95% CI: −0.103 to 0.028) and for the subgroup of patients with current MDD (B = 0.059; 95% CI: −0.037 to 0.165). Also IL-6 did not indirectly affect depressive symptoms through KYN/TRP in the total group (B = −0.023; 95% CI: −0.093 to 0.045) and in the MDD subgroup B = 0.052; 95% CI: −0.019 to 0.144). Finally, no significant relation between depressive symptoms and KYN/TRP was found in the whole group (β = −0.019, p = 0.311) nor in the subgroup with MDD (β = 0.025, p = 0.424). Conclusions We did not find indications for tryptophan degradation, measured by KYN/TRP, to mediate the relationship between inflammation and depressive symptoms. Keywords: Indoleamine 2,3-dioxygenase, Depressive symptoms, Depression, Tryptophan, Kynurenine, Inflammatio

Associations between depressive and anxiety disorders and characteristics with inflammatory markers

Stress-related psychiatric disorders across the life spa