Depression is a life threatening psychiatric disorder. STAR-D study stated that remission rates decrease, and relapse rates increase. It produces chronic diseases and worsens mean health when co-morbid with these diseases. The depressive symptoms in humans are analogous to the ‘sickness behavior’ syndrome seen in animals when injected by pro-inflammatory cytokines.

This study was done to clarify the relation between the severity of depression and serum level of tumor necrosis factor alpha (TNF), so improving the quality of pharmacological management.

This study was done to prove that inflammatory process is involved in the pathogenesis of depression by assessing the serum level tumor necrosis factor alpha (TNF alpha)

Our study is comparing between 60 patients with major depressive disorder and 30 healthy controls regarding the serum level of tumor necrosis factor alpha. Patients were diagnosed by a semi-structured interview using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Patients were subdivided into mild, moderate and severe depression according to Hamilton Rating Scale for Depression (17 items). Assessment of serum level of tumor necrosis factor alpha was done using enzyme- linked immunoassay technique.

Serum level of TNF alpha was significantly higher among patients than among controls (Z = 4.710* P ≤ 0.001*) regardless the severity of depression.

Serum TNF alpha can be used as a biomarker of depression but not for the disorder severity. However, further study is needed to detect if there is a relation between major depressive disorder and serum level of other inflammatory markers as C-reactive protein.

The authors have not supplied their declaration of competing interest.