It should also be noted that dextrorphan, according to William White is responsible for the stoned feeling of DXM trips, while the dextromethorphan itself is responsible for the more psychedelic aspects. Mr. White seems to be undecided about this, however.
Dividing the doses, or preloading, or just a metabolic fluke can lead some DXM trips to be exuberant and psychedelic, while others are stony and dizzy. This could be because of the varying effects of DXM and DXO, or it could just be that drugs that mess with Glutamate ain't nothing to mess with, the great number of Winamp visualization devices notwithstanding.