comes from a psilocybin-assisted smoking cessation study
carried out at the Johns Hopkins University School of Medicine in Maryland, USA 
The form of treatment consisted of up to three psilocybin sessions additional to cognitive behavioral therapy. Twelve out of fifteen participants (80%) succeeded in quitting their habit after this treatment for a minimum of six months . Participants experienced an increased faith to effectively deal with the addiction, a heightened spiritual awareness and an uplifted state of overall well-being. An interesting finding was that, although three participants didn’t succeed in quitting, this group turned out smoking less cigarettes a day six months after the beginning of the treatment.
Because of the study design lacking a control group, it is not (yet) possible to solely ascribe the therapeutic effect of the treatment to the characteristics of psilocybin. Nevertheless, these results promise a better treatment perspective for psilocybin combined with cognitive behavioral therapy than for regular treatment options. The success rate in this study being 80%, compared to 25% to 34% when treated with buproprion or varenicline respectively , or compared to around 50% when treated with a combination of bupropion, nicotine replacement, and intensive cognitive behavioral therapy . More scientific studies would be necessary in order to understand the full potential of treating smoking addiction with psilocybin or other pharmacons that have their mechanism of action on the 5-HT2A-receptor.
The idea of using psychedelics to fight addiction is nothing new. In the 50s and 60s there were a lot of research projects focusing on the therapeutic potential of these compounds. The interested reader might want to take a look at a meta-analysis by Teri Krebs (2012), which, based on six of these studies, concluded that the treatment of alcoholism using LSD seemed to be very effective.
 World Health Organization (2011)
 Johnson, Garcia-Romeu, Cosimano, & Griffiths (2014)
 The notion should be considered that several participants indicated to have a relapse period between the last psilocybin session and six month follow-up, but that they were able to correct it themselves and continued as non-smokers until follow-up.
 Gonzales et al., 2014; Jorenby et al., 2014
 Hall et al., 2009; Killen et al., 2008
 Success rates are based on 7 day point prevalence abstinence measures of smoking behavior. Gathered by self-report and urine- and breath analyzes.
Gonzales, D., Rennard, S. I., Nides, M., Oncken, C., Azoulay, S., Billing, C. B., … Reeves, K. R. (2014). Varenicline, an ␣ 4 ␤ 2 Nicotinic Acetylcholine Receptor Partial Agonist, vs Sustained-Release Bupropion and Placebo for Smoking Cessation, 296(1), 47–55.
Hall, S. M., Humfleet, G. L., Muñoz, R. F., et al. (2009). Extended treatment of older cigarette smokers. Addiction, 104, 1043-1052
Johnson, M. W., Garcia-Romeu, A., Cosimano, M. P., & Griffiths, R. R. (2014). Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction. Journal of Psychopharmacology (Oxford, England), (September). doi:10.1177/0269881114548296
Jorenby, D. E., Hays, J. T., Rigotti, N. A., Azoulay, S., Watsky, E. J., Williams, K. E., … Reeves, K. R. (2014). Efficacy of Varenicline, an α4β2 Nicotinic Acetylcholine Receptor Partial Agonist, vs Placebo or Sustained-Release Bupropion for Smoking CessationA Randomized Controlled Trial. JAMA, 296, 56-63.
Killen, J. D., Fortmann, S. P., Schatzberg, A. F., et al. (2008). Extended cognitive behavior therapy for cigarette smoking cessation. Addiction, 103, 1381-1390.
Krebs, T. S., & Johansen, P.-Ø. (2012). Lysergic acid diethylamide (LSD) for alcoholism: meta-analysis of randomized controlled trials. Journal of Psychopharmacology (Oxford, England), 26(7), 994–1002. doi:10.1177/0269881112439253