Abstract:

Depression refers to a series of mental health issues characterized by loss of interest and enjoyment in everyday life, low mood and selected emotional, cognitive, physical and behavioral symptoms. Depression is a common disorder, affecting 5–15% of the general population. When diagnosed as major depressive disorder (MDD), patients are currently treated with pharmacological agents such as serotonin or noradrenaline  uptake inhibitors (SSRI or SNRI) or tricyclics. Patients that fail to respond to two or more antidepressant drugs - at an adequate dose for an adequate duration given sequentially – are considered affected by “treatment-resistant depression (TRD)”. TRD patients account for the 12–28% of the total MDD patients in charge to mental health services and are generally eligible to adjunctive pharmacotherapies with antipsychotics or lithium, behavioral therapies or electroconvulsive treatment (ECT). Unfortunately, several TRD patients display a persistent lack of response to the current adjunctive treatments, resulting in a relevant social burden and incurring in high direct medical costs to the health care system.