Understanding variations in knowledge and attitudes of psychiatrists to psilocybin therapy is important for the collective discourse about the potential impact on clinical practice and public health in Ireland.

A 28-item questionnaire was designed based on previous studies and distributed to psychiatrists in Ireland via online mailing lists and at in-person academic events.

151 psychiatrists completed the questionnaire (73.3% were under 40 years of age, 76.0% were trainees, and 49.0% were female). In the total sample, 81.5% agreed that psilocybin therapy shows promise in the treatment of psychiatric disorders and 86.8% supported funding research, 86.8% would be willing to refer a patient if it was licensed and indicated, and 78.1% would consider the treatment for themselves, if indicated. Conversely, 6.6% agreed that psilocybin therapy was unsafe even under medical supervision, and 21.9% thought it was potentially addictive. 15.9% of the total sample reported at least one concern including, lack of robust evidence, long-term effectiveness, superiority to current interventions, potential harmful effects, cost and accessibility, and impartiality. Less than half of respondents felt knowledgeable (40.0%) and 9.9% felt adequately prepared to participate in psilocybin therapy. Consultant psychiatrists trended towards less optimism for a potential role in bipolar depression and emotionally unstable personality disorder compared to trainee psychiatrists.

Overall psychiatrists in Ireland held positive attitudes towards psilocybin therapy. However, there was a lack of knowledge evident. Addressing the knowledge gap and aligning with the best available evidence will be key if psychedelic therapy is to prevail in a clinical setting.

Psilocybin Therapy (PT) is being increasingly studied as a psychiatric intervention. Personality relates to mental health and can be used to probe the nature of PT's therapeutic action.

In a phase 2, double-blind, randomized, active comparator controlled trial involving patients with moderate-to-severe major depressive disorder, we compared psilocybin with escitalopram, over a core 6-week trial period. Five-Factor model personality domains, Big Five Aspect Scale Openness aspects, Absorption, and Impulsivity were measured at Baseline, Week 6, and Month 6 follow-up.

PT was associated with decreases in neuroticism (B = −0.63), introversion (B = −0.38), disagreeableness (B = −0.47), impulsivity (B = −0.40), and increases in absorption (B = 0.32), conscientiousness (B = 0.30), and openness (B = 0.23) at week 6, with neuroticism (B = −0.47) and disagreeableness (B = −0.41) remaining decreased at month 6. Escitalopram Treatment (ET) was associated with decreases in neuroticism (B = −0.38), disagreeableness (B = −0.26), impulsivity (B = −0.35), and increases in openness (B = 0.28) at week 6, with neuroticism (B = −0.46) remaining decreased at month 6. No significant between-condition differences were observed.

Personality changes across both conditions were in a direction consistent with improved mental health. With the possible exception of trait absorption, there were no compelling between-condition differences warranting conclusions regarding a selective action of PT (v. ET) on personality; however, post-ET changes in personality were significantly moderated by pre-trial positive expectancy for escitalopram, whereas expectancy did not moderate response to PT.