Endogenous depression(melancholia) is an atypical subclass of major depressive disorder (clinical depression). It could be caused by genetic and biological factors.[1] Endogenous depression occurs due to the presence of an internal (cognitive, biological) stressor instead of an external (social, environmental) stressor.[2] Endogenous depression includes patients with treatment-resistant, non-psychotic, major depressive disorder, characterized by abnormal behavior of the endogenous opioid system but not the monoaminergic system.[3][4][5] Symptoms vary in severity, type, and frequency and can be attributed to cognitive, social, biological, or environmental factors that result in persistent feelings of sadness and distress. Since symptoms are due to a biological phenomenon, prevalence rates tend to be higher in older adults.[6] Due to this fact, biological-focused treatment plans are often used in therapy to ensure the best prognosis.[2]
^Matsunami, Katsufumi (2013). "The clinical meaning and academic significance of "endogenous depression" as an ideal type". Seishin Shinkeigaku Zasshi = Psychiatria et Neurologia Japonica. 115 (3): 267–276. ISSN0033-2658. PMID23691813.
^Nyhuis PW, Specka M, Gastpar M (2006). "Does the antidepressive response to opiate treatment describe a subtype of depression?". European Neuropsychopharmacology. 16 (S4): S309. doi:10.1016/S0924-977X(06)70328-5. S2CID54365563.
^Bodkin, JA; Zornberg, GL; Lukas, SE; Cole, JO (February 1995). "Harvard Medical School Clinical Study "Buprenorphine treatment of refractory depression."". Journal of Clinical Psychopharmacology. 15 (1): 49–57. doi:10.1097/00004714-199502000-00008. PMID7714228.
^Bodkin, J. Alexander; Zornberg, Gwen L.; Lukas, Scott E.; Cole, Jonathan O. (February 1995). "Buprenorphine Treatment of Refractory Depression". Journal of Clinical Psychopharmacology. 15 (1): 49–57. doi:10.1097/00004714-199502000-00008. PMID7714228.