Table 3.
Interactions between Cortisol and RSA as Moderators of Internalizing Symptoms
| Step and Variables | R2 | Δ R2 | β | X2(df) | Δ X2 (Δdf) | |
|---|---|---|---|---|---|---|
|
Depressive Symptoms (CDI)-Study 1 | ||||||
| Step 1: | Control variables | .151 | .151 | 9.117(4) | ||
| Step 2: | Cortisol | .166 | .015 | .151 | 8.014(2) | 1.103(2) |
| RSA | .101 | |||||
| Step 3: | Cortisol X RSA | .292 | .126 | −.402** | .073(1) | 7.941(1)** 9.044(3)* |
|
Anxiety Symptoms (RCMAS)-Study 1 | ||||||
| Step 1: | Control variables | .196 | .196 | 11.470(4) | ||
| Step 2: | Cortisol | .204 | .008 | −.072 | 10.852(2) | 0.618(2) |
| RSA | −.099 | |||||
| Step 3: | Cortisol X RSA | .344 | .140 | −.433*** | .073(1) | 10.779(1)** 11.397(3)** |
|
Depressive Symptoms (CDI)-Study 2 | ||||||
| Step 1: | Control variables | .029 | .029 | 6.172(4) | ||
| Step 2: | Cortisol | .041 | .012 | −.038 | 3.996(2) | 2.176(2) |
| RSA | −.102 | |||||
| Step 3: | Cortisol X RSA | .058 | .017 | −.135† | .875(1) | 3.121(1) † 5.297(3) |
|
Anxiety Symptoms (TSCC)-Study 2 | ||||||
| Step 1: | Control variables | .030 | .030 | 8.858(4) | ||
| Step 2: | Cortisol | .055 | .025 | −.079 | 4.173(2) | 4.685(2) |
| RSA-B2 | −.133† | |||||
| Step 3: | Cortisol X RSA-B2 | .077 | .022 | −.144† | .829(1) | 3.344(1) † 8.029(3)* |
Note. In the first path analytic model, child age, gender, ethnicity, SES, start time of cortisol intake, and externalizing behavior (collectively referred to as control variables) were entered. In the second model, main effects were entered: cortisol and RSA. For each model, the ΔX2 (Δdf) for step 3 was calculated based on the initial model as well as the previous model. Unit of measurement for salivary cortisol is μg/dl and the unit of measurement of RSA is seconds. RSA Respiratory Sinus Arrhythmia; CDI Child Depression Inventory; RCMAS Revised Child Manifest Anxiety Checklist; TSCC Trauma Symptoms Checklist for Children.
†
p < .10;
*
p ≤ .05;
**
p < .01;
***
p < .001.