Relationship of cortisol and alpha amylase to behavioral engagement under three levels of negative evaluative psychosocial stress.

Despite that behavioral engagement is integral to mental health, surprisingly little is known about the relationship of psychosocial stress and behavioral engagement. The current study developed an observer-rated measure of behavioral engagement for lab-based stress inductions, then examined its relationship with stress-responsive biomarkers and affect. Young adults (N = 109, Mage=19.4, SDage=1.59, 57% female) completed one of three Trier Social Stress Test (TSST) conditions-non-stressful Control, Intermediate, or an Explicit Negative Evaluative-and at four timepoints provided self-reports of positive and negative affect and saliva samples for cortisol and salivary alpha-amylase (sAA). Trained study staff (experimenters and TSST judges) completed a programmed questionnaire measure of the novel behavioral engagement measure after the participants completed the TSST. Psychometric review and EFA of the behavioral engagement items resulted in a final 8-item measure with good interrater reliability and well-fitting 2-factor structure, capturing Persistence (4 items; loadings=.41-.89), and Quality of Speech (4 items; loadings=.53-.92). Results indicated that the relationship of positive affect growth and biomarker level to behavioral engagement varied substantially as a function of context: As negative evaluation level strengthened, behavioral engagement became more tightly associated with relative preservation of positive affect. For both cortisol and sAA, the relationship between biomarker levels (but not reactivity) and behavioral engagement varied significantly by condition, such that under milder conditions and elevated levels of biomarkers, engagement was greater, but under Explicit Negative Evaluation, and elevated levels of biomarkers, engagement was less, suggesting behavioral withdrawal. Findings reveal the critical role of context-especially negative evaluation-in the relationship of biomarkers with behavioral engagement.

Additive serotonergic genetic sensitivity and cortisol reactivity to lab-based social evaluative stress: Influence of severity across two samples.

Prior work demonstrates that an additive serotonergic multilocus genetic profile score (MGPS) predicts amplified risk for depression following significant life stress, and that it interacts with elevations in the cortisol awakening response to predict depression. The serotonin system and HPA-axis have bidirectional influence, but whether this MGPS predicts acute cortisol reactivity, which might then serve as a mechanism for depression, is unknown. Our prior work suggests that depression risk factors predict blunted cortisol reactivity to explicit negative evaluative lab-based stress. Thus, we hypothesized that a 4-variant serotonergic MGPS (three SNPs from the original 5-variant version plus 5HTTLPR) would predict blunted cortisol reactivity to explicit negative evaluative stress versus a control. In Sample 1, growth curve modeling showed that the MGPS predicted heightened cortisol reactivity (p = 0.0001) in an explicitly negative evaluative Trier Social Stress Test variant (TSST) versus a control condition among non-depressed emerging adults (N = 152; 57% female). In Sample 2, 125 males completed the Socially Evaluative Cold Pressor Test (SECPT), an ambiguously negative evaluative manipulation; findings displayed a similar pattern but did not reach statistical significance (ps.075-.091). A participant-level meta-analysis of the two samples demonstrated a significant effect of negative evaluation severity, such that the MGPS effect size on reactivity increased linearly from control to SECPT to an explicitly negative evaluative TSST. Findings indicate that this MGPS contributes to sensitivity to social threat and that cortisol dysregulation in the context of social stress may be one mechanism by which this MGPS contributes to depression.