This educational text provides a comprehensive overview of depressive disorders, focusing on their clinical classification, biological origins, and nursing management. It details various conditions ranging from major depressive disorder and persistent depressive disorder to newer diagnoses like disruptive mood dysregulation disorder. The material emphasizes the diathesis-stress model, explaining how genetic predispositions and environmental triggers disrupt neurotransmitters like serotonin and norepinephrine. Readers are guided through the nursing process, which includes suicide risk assessment, the identification of vegetative symptoms, and the implementation of evidence-based interventions. Finally, the source evaluates modern treatment modalities, covering pharmacotherapy, psychotherapy, and advanced brain stimulation therapies such as electroconvulsive therapy and deep brain stimulation.