You might want to check out the following article:
www.ncbi.nlm.nih.gov/pmc/articles/PMC3225003/
This report seems to be compatible with our findings from evaluating treatment outcomes. Injecting anything was found to be associated with greater risk for relapse. This would seem to suggest a more advanced stage of the addiction and/or greater severity as suggested in the article.
Thank you Dr. Hoffmann this helpful. Like this article, most comparisons I found was between injectors and non-injectors. However we see a big profile difference (and possible outcome differences as well) between snorters and smokers. As so I would like to compare all 3 groups (injectors, snorters and smokers). Anyways thanks a lot for your help.