Clinical features and diagnosis
The core clinical features of depression include physical (sleep and appetite disturbances, psychomotor changes, fatigue, low energy), emotional (sadness, loss of interest, anhedonia), and cognitive (guilt, suicidal thoughts and behaviours, concentration and memory difficulties, indecisiveness) symptoms. DSM-5 classifies depressive disorders in adults as major depressive disorder (MDD), other depressive disorders, and persistent depressive disorder; the latter includes chronic MDD, unremitted MDD, and dysthymia (chronic, low-grade depressive symptoms). DSM-5 also includes specifiers, or sub-types, of MDD that have implications for prognosis and treatment choice and selection. The differential diagnosis of depression includes bereavement, bipolar disorder, and other medical or substance-induced conditions.