The long-term course of anxiety, depression and the comorbid disorder is not well understood.

Data were derived from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a prospective population based study and the Netherlands Study of Depression and Anxiety (NESDA), also a prospective study with patients form primary and specialist outpatient care.

The two year course of anxiety and depression in NESDA is best for depressive disorders, than for anxiety disorders and worse for the comorbid anxiety-depressive disorders with a median duration of depression 6 months, anxiety 16 months and comorbid depression-anxiety >24 months. Severity of the index episode, longer duration at baseline and early onset are predictors of a unfavourable course. Avoidance behaviour seems to predict a longer duration for the anxiety disorders.

The course of major depressive disorder (MDD) in NEMESIS is better than for dysthymia and double depression. The cumulative incidence of recurrence of MDD after 20 years is 42% and recurrence is predicted by younger age of onset, previous episodes, severity of index episode, daily hassles and negative youth experiences.

The long-term course anxiety and depression is unfavourable, especially for the comorbid condition Recurrence of MDD is high, even in the general population. Knowledge of the predictors of unfavourable course may help to distinguish the patients at risk.