The correct ICD-10 code for chronic depression is F33.1. This code represents major depressive disorder, recurrent, moderate. For persistent depressive disorder (dysthymia), use F34.1. Chronic depression ICD-10 billing most often uses F33.1 when a patient has repeated moderate depressive episodes. Document episode frequency, severity, and functional impact. Medical necessity requires ongoing symptoms for at least two years (for F34.1) or multiple distinct episodes […]