Prevalence of depressive illness

Unipolar depressive illness affects 5% of the population. Depressive illness is much commoner in women than men [approximately twice as common]. It can start at any age from adolescence onwards. In women the highest rates occur between the ages of 35 and 45 years. In men it becomes more common with increasing age.

Recent trends suggest that it is becoming more common [or more commonly diagnosed] in younger age groups. 12-20% of people with a depressive illness develop a chronic depressive illness i.e. lasts more than 2 years.