Book excerpt: This book is written for researchers, undergraduate students and postgraduate students, physicians and traditional medicine practitioners who develop research in the field of neurosciences, phytochemistry and ethnopharmacology or can be useful for their practice. Topics discussed include the description of depression, its biochemical causes, the targets of antidepressant drugs, animal and cell models commonly used in the research of this pathology, medicinal plants and bioactive compounds with antidepressant activity used in traditional medicine, advances in nanotechnology for drug delivery to the brain and finally the future challenges for researchers studying this pathology.