Meta-correlation of the effect of ketamine and psilocybin induced subjective effects on therapeutic outcome
Bostoen, T., Dadiomov, D., Dahan, A., Dahan, J. D. C.
This meta-analysis (2024, s=31) examines the correlation between subjective effects and therapeutic outcomes for ketamine (s=23, n=471) and psilocybin (s=8, n=183) in depression and substance use disorder (SUD) treatment. It finds modest mediating effects of subjective experiences on therapeutic outcomes, with psilocybin showing a stronger mediating effect (R² = 24%) compared to ketamine (R² = 5-10%), and a greater mediating effect observed in SUD compared to depression regardless of the substance used.
Abstract
There is some evidence that the subjective effects of ketamine and other psychedelics like psilocybin are crucial for their therapeutic outcomes, such as treatment of depression or substance use disorder (SUD). We performed a meta-analysis and systematic review on the correlation of subjective symptoms and dissociation versus ketamine-induced therapeutic outcomes in patients with depression or SUD. A similar analysis was conducted for psilocybin-induced therapeutic improvement. We retrieved 23 papers studying ketamine (21 on depression, 2 on SUD) in 471 patients and 8 papers studying psilocybin (6 on depression, 2 on SUD) in 183 patients. Our study demonstrated a modest role for subjective effects mediating therapeutic outcomes, with R2-values ranging from 5-10% for ketamine and for psilocybin the R2 was 24%. A greater mediating effect for psilocybin compared to ketamine was detected, particularly when restricting the analysis to depression. Additionally there is a greater mediating effect in SUD than depression, irrespective of treatment.