Pioneers of nosology in psychiatry considered mental deficit as a basic disorder obligated to all clinical forms of illness, as did E. Kraepelin in the concept of dementia praecox and E. Bleuler in the concept of schizophrenia. At the present stage of studies, this position is clearly articulated in the «deficit schizophrenia» concept of J. Klosterkotter. Negative disorders are considered in categorical approach to interpret psychopathological dimensions of schizophrenia as coordinated, strongly bound with positive syndromes (concept of «dialectical unity» of A.V. Snezhnevskiy, 1964) and classified as syndromes according to systematics of positive disorders. However, distinguished types of negative disorders are determined in terms of positive syndromes or characterological changes (asthenic, pseudopsychopathic deficit). Within a new paradigm (dimensional approach to schizophrenia), which differs from the categorical approach, negative disorders are considered as a distinct domain, primary in relation to other psychopathological phenomena of schizophrenia). A concept of primary persistent negative symptoms serves as basis of the current concept of schizophrenic deficit. Factor analysis revealed two domains of negative disorders: 1) emotional blunting: blunted affect, alogia; 2) avolition: apathy, anhedonia, asociality.