Association of serum cortisol level with severity of depression and improvement in newly diagnosed patients with major depressive disorder in Jimma medical center, Southwest Ethiopia

BACKGROUND: Major Depressive Disorder (MDD) is the leading psychiatric disorder in low- and middle-income countries, and is to be the second leading cause of burden of disease by 2020. Cortisol plays a significant role in pathophysiology of MDD. Depression can alter serum cortisol level. However, the change in serum cortisol level and its association with depressive symptom severity and improvement among patients with MDD is not well studied. OBJECTIVE: To outline change in serum cortisol levels and its association with severity and improvement of depressive symptoms in newly diagnosed patients with MDD. METHOD: Hospital based longitudinal study was conducted among 34 newly diagnosed patients who met DSM-V criteria of MDD. Venous blood sample was performed twice; pre- and post- 8 weeks of treatment. Serum cortisol concentration was measured using an extracted radioimmunoassay. The 17-item Hamilton Depression Scale (HAM-D) was used to rate depression at baseline and after 8 weeks of treatment. Paired t-test was done to look the mean difference of serum cortisol level and HAM-D, before and after treatment. Pearson correlation was done to look the association between serum cortisol levels, HAM-D scores and, sociodemographic and clinical factors. Statistical significance was set at p<0.05. RESULTS: There is no significant difference in cortisol concentrations at baseline and end line (t (33) = 2.02, p = 0.052). However, there is significant difference in HAM-D total score (t (33) = 5.67, p<0.001). Baseline and end line serum cortisol levels were significantly correlated (r = .561, p = .001). Monthly family income is correlated with baseline HAM-D total score (r = -0.373, p = .030). There is no significant relationship between baseline serum cortisol level and HAM-D score. There is also no significant relationship between end line serum cortisol level and HAM-D score. CONCLUSIONS: The symptoms of MDD were reduced following treatment but there is no significant difference in serum cortisol levels. Baseline and end line serum cortisol levels were significantly correlated. We recommend further research based on large sample.