ABSTRACT: The purpose of this article is to summarize the results of studies examining the validity of the positive and negative sub-types of schizophrenia as proposed by Crow. The authors summarized Crow's model's predictions in the form of 12 research questions and examined whether its predictions were confirmed. The following predictions are generally confirmed by the data collected: (i) it is possible to measure negative symptoms with accuracy; (ii) the negative symptoms predict a deterioration; (iii) the negative symptoms are generally correlated with overall cognitive deficits; (iv) each dimension appears to have distinct neurobiological substrata. However, several elements of the Crow model are not supported by the data collected. Among the necessary modifications, the most important are as follows: (i) it appears more productive to conceive of the negative symptoms as distinct dimensions, rather than distinct diseases; (ii) at least three dimensions exist for describing the symptoms of schizophrenia; (iii) the negative symptoms are not necessarily intrinsic to the schizophrenic process, and they may be due to other causes; (iv) the negative symptoms are not necessarily irreversible, and can be improved under ataractics; (v) the positive symptoms, in particular those relating to disorganization, can also be correlated with cognitive deficits.
Canadian journal of psychiatry. Revue canadienne de psychiatrie 10/1994; 39(7):407-14. · 2.42 Impact Factor