RESUMEN
Results of research comparing the Deficit Index (d.i.) of the Halstead-Reitan Neuropsychological Battery (HRN-B) and the Deterioration Index (DI) of the Weschler's scale (WAIS) are presented. The tests were applied to obtain a neuropsychological evaluation of two groups: chronic solvent-users and non-users. The subjects were from a marginal community and were observed during one year. They were evaluated at the beginning and end of the year on patterns of consumption and cognitive damage. The results showed that during the year of the study: 58 percent of users abandoned drug use; 33 percent changed to occasional consumption and 8.3 percent maintained their consumption pattern 58 percent non-users continued a non-consumption pattern and 41 percent began experimental consumption. In relation to these results, users changed their cognitive performance from "moderate damage" to "light damage", according to the Deficit Index (HRN-B); non-users remained in this last level. In relation to the Deterioration Index (WAIS), this was invalidated in the first evaluation. In the second, users obtained "clinical significance" and non-users "suspect damage". In conclusion, Deficit Index (HRN-B) data showed more consistent changes in consumption patterns than Deterioration Index (WAIS). These results are discussed in terms of changes in patterns of consumption and other variables.