Resistant Depression

Abstract

The term resistant points out a clinical phenomenon in which there is a lack of response to one or more therapeutic interventions. Resistance to major depressive disorder treatment causes distress to patients and their relatives, and increases the number of hospital admissions, outpatient consultations, use of psychoactive drugs, and treatment costs. Despite its serious medical and psychosocial medical implications, the definition of treatment resistant depression continues to be ambiguous and controversial. The lack of an agreement on definition, as well as the research on the subject being difficult, limits the practical knowledge on the best treatment options for groups of treatment resistant depression (TRD) patients. We review the concept and definitions of treatment resistant depression as well as the medical literature on different treatment methods studied and comparative studies. Finally, some relevant neurobiological data are reviewed.