The aim of this chapter was to analyze associations between measures of cortisol in saliva
and mental health and to see if divergent results were functions of the methods used. Measures of
mental health outcome included Major Depressive Disorder (MDD), symptoms of depression, and
symptoms of anxiety, Burnout (BO), and Vital Exhaustion (VE). Only studies on otherwise healthy
individuals were included. Cortisol measures were grouped into single time point measures, measures
of deviations, laboratory test responses, Area Under the Curve (AUC), and response to dexamethasone.
Some consistency is seen for MDD, mainly higher mean levels. The results regarding single measures
and depressive mood are less consistent, but the overall picture for depression shows poorer diurnal
deviation and response to stress. Inconsistency among papers studying depression seems to be related
mainly to the study population. Very few significant findings were found for anxiety, therefore cortisol
does not seem to be strongly related to anxiety. Most of the statistical analysis does not show a
significant relationship between BO and cortisol, and when these are present, the results are
inconsistent. One explanation seems to be the measures of BO used, probably due to the different
conceptual basis for BO. VE measured using the Maastricht Questionnaire seems to be related to a
poorer cortisol response to stress and poorer diurnal deviation. The coexistence of BO and VE in many
studies does make it difficult to conclude how the different concepts are related to cortisol. However, an
interesting difference appeared between MDD and VE in response to dexamethasone administration,
showing lower suppression in MDD patients and higher suppression in VE patients. A general
conclusion for all mental health measures is that a large proportion of non-significant findings are due
to low power and few sampling days combined with low contrasts between study groups and within
study populations. Generally, deviation measures such as diurnal deviation seem to be more valid
measures compared with single measures to capture possible changes in the hypothalamus-pituitaryadrenal
axis, measured using salivary cortisol.
Keywords: Salivary cortisol, depression, anxiety, major depression disorder, burnout, vital exhaustion,
single time point measures, deviations measures, area under the curve, laboratory test, dexamethasone.
