Models of the etiology of depressive disorders suggest that the
onset of a depressive episode is the result of a complex phenomenon
based on the interaction between genetic background, critical environmen-
tal factors such as life stressors and traumatic events, and the effects of
neuroendocrine changes associated with the stress response. Numerous
studies have highlighted the usefulness of morning cortisol (C) as a poten-
tial predictor of depressive episodes. The aim of this study was to compare
the effectiveness of C, salivary alpha-amylase (sAA) activity/output, and
the sAA/C ratio in predicting depressive symptoms in a community sam-
ple of 99 children aged 8-11 years old. Two saliva samples were obtained
in the morning on two different school days. Teachers described their pu-
pils' behavior by using the internalizing problems scales of the Teacher’s Re-
port Form (TRF) questionnaire. Our results indicate that, regardless of gen-
der, the best predictor of depressive/withdrawal scores and overall inter-
nalizing scores on the TRF was lower mean morning levels of sAA activi-
ty. Hence, sAA could be proposed as a biological marker for the risk of
developing a first episode of depressive illness in child samples.
