Abstract

Anxiety symptoms may strain underlying biological systems to result in negative long-term health consequences. In addition to generating psychological distress, anxiety symptoms may affect the system’s ability to respond optimally to stress, and impede endocrine and immune functioning over time. To date, the literature shows inconsistent findings regarding the nature and directionality of the relationship between anxiety symptoms and biomarkers of the immuno-endocrine systems. To explore how different dimensions of anxiety symptoms (physiological versus cognitive-emotional) interact with and affect the underlying immuno-endocrine systems over time from childhood to adolescence, the current studies examined the following questions: (1) How and in what direction are anxiety symptoms associated with diurnal cortisol rhythms concurrently and longitudinally?; (2) Is there an association between anxiety and diurnal salivary immunoglobulin A (sIgA)?; (3) How and in what direction are anxiety symptoms related to overall sIgA levels?; and (4) Are there feedback mechanisms, whereby anxiety symptoms and immuno-endocrine biomarkers create a chain of sequential cause and effect, with each affecting the other in a transactional sequence over several years?
Data were collected from participants in the Concordia Longitudinal Risk Project between the ages of 9 to 18 using a multi-wave design. Repeated measures of self-report symptom questionnaires, salivary samples of endocrine and immune biomarkers, and demographic information were collected at each data wave approximately three years apart. Hierarchical linear modeling and autoregressive cross-lagged panel designs were used to analyze the data. Results showed that higher physiological anxiety symptoms were concurrently associated with elevated diurnal cortisol, whereas longitudinal results over three years showed that chronic worry and social concerns predicted lower diurnal cortisol, illustrating a more blunted diurnal cortisol profile. Diurnal sIgA results revealed a pattern of activation in children with higher anxiety, specifically, worries and social concerns, than those with lower anxiety. Higher levels of total anxiety, worries and social concerns also led to lower levels of sIgA, which in turn led to increases in anxiety in an incremental “vicious” cycle from age 9 to 18. Taken together, these findings have important implications for understanding the developmental psychobiology of children’s anxiety.