Therapeutic Effects of Psilocybin

"Regarding results, on depression and anxiety symptomatology,⁴ studies^16,21,27,32 consistently showed immediate and enduring antidepressant and anxiolytic effects. Notably, results have shown BDI score reductions lasting as long as 6 months¹⁶ and reaching as high as 83% anti-depressant response and 85% remission rates (defined by BDI scores),⁷ weeks following a single dose of psilocybin.²¹ Significant reductions were also reported on other depression measures such as QIDS,GRID-HAMD-17 or MADRS. Furthermore, significant evidence for anxiety symptom reduction was also observed on scales such as STAI and HAM-A, with reports of 76% and 52% of response and remission rates, respectively²⁷ (defined by HAM-A scores). Regarding OCD, 1 open-label study has found symptomatic relief and significant reductions on YBOCS scores.^39,56–58 On tobacco addiction, 2 open-label studies regarding the same experiment have showed abstinence on 80% of the subjects after 3 months and on 67% after 9 months from the final dose session. In addition, 60% were biologically verified as abstinent roughly 27 months after the last dose session. Nevertheless, these 2 studies did not differentiate the effects of moderate and high doses. In regard to alcohol abuse, the open-label study reported significant reductions on the percent of heavy drinking days and percent of drinking days to up to 28 weeks. However, it was not able to differentiate the effects of the 2 doses used. Although the level and quality of evidence for psilocybin on substance use disorder are low, the preliminary results published so far are promising and have motivated researchers to conduct larger controlled trials: a 50-participant study on psilocybin-facilitated smoking cessation treatment (NCT01943994), a 180-participant study on psilocybin-assisted treatment of alcohol dependence (NCT02061293), the first study on psilocybin-facilitated treatment for cocaine use (NCT02037126) and multiple studies on depression (NCT03775200, NCT03429075, NCT03715127, NCT03181529, NCT03380442, NCT03554174, NCT03866174) and OCD (NCT03356483, NCT03300947). Overall the results obtained across studies are impressive, given that few administrations show long lasting effects, well beyond the time course of the acute drug effects. Moreover, the studies on different disorders have coherently shown a significant therapeutic effect."