The central nervous system (CNS) activity has been investigated by using a topological substructural molecular approach (TOPS芒芒芒MODE). A discriminant analysis to classify CNS and non-CNS drugs was developed on a data set (302 compounds) of great structural variability where more than 81%(247/302) were well classified. Randic芒芒芒s orthogonalization procedures was carried out to allow the interpretation of the model and to avoid the collinearity among descriptors.