It is well known that the great majority of patients presenting psychiatric symptoms are treated by GPs rather than by specialist psychiatric personnel (Shepherd et al. 1966). Goldberg & Huxley (1980) have proposed a model to describe psychiatric disorders and their care, consisting of five levels and four filters. Level 1 refers to psychiatric and emotional disorders in the community as a whole, and filter 1 represents the decision to, and act of, consulting a GP. Level 2 consists of all psychiatric morbidity that presents to GPs, although a proportion is not recognized as such (the hidden psychiatric morbidity – HPM). Filter 2 is thus the process of identification, and level 3 refers to the morbidity so identified (the conspicuous psychiatric morbidity – CPM). Filter 3 is the process of referral to the specialist psychiatric services, the patients of which are designated as level 4. A proportion of patients at this level will be admitted to hospital (i.e. will pass through filter 4) and reach level 5 (psychiatric in-patients).