Significant reductions from baseline to the final on-treatment assessment on the oppositional subscale of the CPRS-R : L were seen with GXR plus psychostimulant compared with placebo plus psychostimulant , both in the overall study population ( placebo-adjusted least squares [ LS ] mean change from baseline to the final on-treatment assessment : GXR a.m. + psychostimulant , -2.4 , p = 0.001 ; GXR p.m. + psychostimulant , -2.2 , p = 0.003 ) as well as in the subgroup of subjects with significant baseline oppositional symptoms ( GXR a.m. + psychostimulant , -3.6 , p = 0.001 ; GXR p.m. + psychostimulant , -2.7 , p = 0.013 ) .