Background: Salivary cortisol level is considered a prominent depression biomarker, as saliva induces less stress as compared to blood.  

Methodology: The study was performed in the physiology department, Sheikh Zayed Medical Institute Lahore from April 2015 to December 2015. Sixty participants, including 14 (46.67%) males and 16 (53.33%) females, in each non-depressive and depressive group of over 17 years of age, were undertaken. 

The depression diagnostics were performed both outdoors and in clinics and confirmed with the standards of the Diagnostic and Statistical Manual of Mental Disorders and Beck's Inventory. Saliva specimens were collected and processed for enzyme-linked immunoassay (ELISA), and absorbance was calculated on a microtiter plate reader.  

Results & Data Analysis: The statistics with the Statistical Package for the Social Packages (SPSS) 26.0 (IBM Corp., Armonk, NY) show that patients of the non-depressive category exhibited mean ages 35.73±6.89 years and 39.10±6.89 years in the depressive group (p-value: 0.178). The mean cortisol level was 1.46±0.91 ng/ml among non-depressive and 2.23±1.69 in depressive patients (p-value: 0.031). The mean depression score among non-depressive was 5.73±4.05 and 52.03±5.08 while there was no statistical difference in the mean height and weight of subjects in normal and depressive patients (p-value: 0.0001). Meanwhile, the mean cortisol level was 1.46±0.91 ng/ml among non-depressive patients, while it was 2.23±1.69 in the depressive group, with no statistical difference in mean ages (p-value: 0.031). These findings proved the cortisol level directly linked with severe depression and useful for depression diagnostics and management. 

Conclusion: These findings recommend that cortisol level may comprise as a biological index of severe depression and add an element to the diagnostics and management of attitude and depression complaints. It also shows the potential significance of long time family history of depression beyond several generations has positive impact on the depressed patients and their effective treatment.