Chapter 7: Depressive Disorders

The chapter categorizes major depression into subtypes including unipolar depression, recurrent depressive episodes, atypical presentations, and psychotic depression, while underscoring the essential importance of screening for manic episodes before initiating antidepressant therapy to avoid precipitating mood destabilization in individuals with bipolar disorder. A substantial portion addresses the biological mechanisms underlying depressive illness, particularly the biogenic amine hypothesis which posits that depression results from dysregulation of monoamine neurotransmitter systems, specifically serotonin, norepinephrine, and dopamine. The chapter explains how these neurotransmitter deficiencies relate to observable symptoms and how various antidepressant classes target these neurochemical systems. Neurovegetative symptoms including sleep architecture disturbances, appetite dysregulation, and fatigue are discussed as biological markers distinguishing endogenous depression from reactive mood states. The treatment section synthesizes multiple intervention modalities including selective serotonin reuptake inhibitors and other pharmacological agents, evidence-based psychotherapy approaches, electroconvulsive therapy for severe or treatment-resistant cases, transcranial magnetic stimulation as a neuromodulatory alternative, and adjunctive lifestyle modifications. The chapter establishes that effective depression management frequently requires integrated treatment combining pharmacotherapy with psychological intervention, recognizing both the neurobiological basis of mood disorders and the role of psychological and social factors in treatment response.