SPEAKERS

Introduction:

Psilocybin therapy shows promise as an intervention for improving a wide range of mental health outcomes (e.g., well-being; Johnson et al., 2018). However, there remains an incomplete understanding of the underlying psychological mechanisms that explain its therapeutic action. Qualitative research suggests that experiential avoidance may play a key role in psilocybin therapy (Watts et al., 2017), suggesting that further research into experiential avoidance as a mechanism underlying psilocybin therapy is warranted. Methods:We conducted a within-subject experimental study in which healthy, psychedelic-naïve, individuals (N=17) were administered a low and high dose of psilocybin. At baseline, as well as 4-weeks after low and high-dose psilocybin, individuals completed self-report measures of experiential avoidance and well-being. Results:A repeated measure ANOVA with post-hoc tests indicated that high dose psilocybin (p=.002; Cohen’s d=3.59), but not low-dose psilocybin (p=.08; d=1.88), led to significant increases in well-being. Similarly, high dose psilocybin (p=.004; d=3.36), but not low-dose psilocybin (p=.269, d=1.15), led to decreases in experiential avoidance. Furthermore, changes in experiential avoidance were significantly associated with changes in well-being following high-dose psilocybin (r=.51, p=.035), but not low-dose psilocybin (r=-.08, p=.769).

Discussion:

Our findings indicate that a single high-dose of psilocybin leads to decreases in experiential avoidance and increases in well-being among healthy individuals. These results suggest that experiential avoidance may be a transdiagnostic mechanism underlying outcomes associated with psilocybin therapy. Furthermore, integrating psilocybin and psychotherapeutic interventions that specifically target experiential avoidance (e.g., acceptance and commitment therapy [ACT]; Hayes, Strosahl, & Wilson, 2012) may optimize treatment outcomes.