Depression is a chronic mental disorder affecting more than 10% of population. The World Health Organization revealed that depression is the fourth leading cause of disability worldwide (WHO,2001). Stressful life events facilitate the evolution of depressive illness as the stress can influence the function of central nervous system by altering a number of neurotransmitters, endocrine, neuro-endocrine and along with other biochemical systems (Gopalakrishna et al.,2010).The most lethal complication of depression is the suicidal behavior (Khandelwal et al., 2001; Sudhaker et al., 2010). Along with the classical theory of decrease in the neurotransmitter levels in the brain leading to the pathogenesis of clinical depression, recent studies have
