ABSTRACT
A lthough depressive illness is very common, its extent varies in different places and in different groups (see Box 1.1). Surveys show that 20-30% of the population m ay suffer sym ptom s of depression in the course of one year. M ost cases are m ild b u t about one person in 20 will have a m oderate or severe episode. Severe depression affects about 3-4% of the population, bu t only one-fifth of this group will seek medical treatm ent. A bout 1 in 50 depressives need hospital treatment.
