Chronic dysphoria can be secondary to a debilitating medical illness, a psychiatric disorder, or both (Akiskal, 1983).
1990, Martin B. Keller, Frances M. Sessa, Lauren P. Jones, “Chapter 7: Chronic Depressive Disorders”, in Barry A. Edelstein, Michel Hersen, M.E. Thase, editors, Handbook of Outpatient Treatment of Adults: Nonpsychotic Mental Disorders, page 145