Salivary Alpha-amylase Enzyme and Salivary Cortisol Level in Depression after Treatment with Fluoxetine

BACKGROUND: Hypothalamic-pituitary-adrenal axis and its end product cortisol have been extensively investigated in patients with depressive disorders for many years. Recently, salivary alpha-amylase (sAA) had emerged as a new biomarker with non-invasive and more convenience protocol for measuring sympathetic activity which was also associated with depression. Selective Serotonin Reuptake Inhibitor is antidepressant drug extensively used to treat depression.
AIM: The aim of this study was to determine whether a decrease of sAA and salivary cortisol levels could be observed in subjects with depression who were treated by fluoxetine.
METHODS: The total subjects were 25 depressed subjects and 10 healthy controls. sAA was examined before therapy and after 2, 4, and 6 weeks of fluoxetine administration using a portable colorimeter. Salivary cortisol was examined before therapy, after 4 and 6 weeks of fluoxetine administration with the Elisa method. The therapeutic effect was assessed with Hamilton Depression Rating Scale (HDRS).RESULTS: sAA and cortisol level were significantly decreased after fluoxetine administration (p < 0.001) followed by at least 50% reduction of HDRS scores after 6 weeks of fluoxetine administration. Levels of sAA and cortisol were higher in the depression group than in the healthy control.
CONCLUSIONS: Measurement of sAA levels can be used as a potential biomarker of therapeutic response in depressed patients in addition to salivary cortisol.