RESUMO
The Psychopharmacological Studies Group of Fann, Dakar, considered the cultural expression of mental illness as it would help for a new definition of the nosographic frames, and inside of them, the appreciation of symptoms. This new definition would be applied "universally" if it may be considered that some symptoms are "culture-free" and others deeply marked by the discourse held by the person or by his social group. The use of valuation scales for symptomatic change during a treatment (here anti-depressive one) become harder by the undifferenciation of these two types of symptoms. Further, it may exist nosographic masks which can hide more curable substructures ; as often happens here, in masked depressions when the presented symptoms are those of acute or chronic psychotic manifestations. The efficacy of depressive treatment is then remarkable.