Journal of psychopharmacology (Oxford, England)
August 1, 2021
Rachael L Sumner, Emme Chacko, Rebecca McMillan et al.
68 citations
Ketamine, given at 0.44 mg/kg to 32 volunteers with major depressive disorder in a crossover design with the active-placebo remifentanil, produced psychedelic experiences that correlated with greater antidepressant response at 24 hours. Specifically, higher scores on spirituality, experience of unity, and insight were linked to larger reductions in depression ratings. Qualitative interviews revealed perceptual changes, loss of control, emotional shifts, a psychedelic afterglow, and lasting changes in perspective on life, people, problems, and depression. The findings suggest the psychedelic experience and afterglow contribute to ketamine's antidepressant effects, and that standard questionnaires may not fully capture these properties.
Scientific reports
January 29, 2025
Richard J Zeifman, Meg J Spriggs, Hannes Kettner et al.
26 citations
A preliminary test of the REBUS model found that a high dose of psilocybin (25 mg) reduced confidence in negative self-beliefs in 11 healthy individuals, both during the acute experience and four weeks later. Greater brain signal entropy and stronger subjective effects under psilocybin correlated with larger decreases in negative self-belief confidence. Decreases in negative self-belief confidence were linked to increases in well-being. The findings provide initial evidence that relaxing and revising negative self-beliefs may underlie psilocybin's positive psychological effects, with increased neuronal entropy as a possible mechanism. Replication in larger clinical samples is needed.
Journal of Psychopharmacology
November 14, 2022
Meg J Spriggs, Bruna Giribaldi, Taylor Lyons et al.
15 citations
A fixed 25 mg dose of psilocybin produces similar acute psychedelic effects and improvements in well-being regardless of body mass index (BMI). Pooling data from three therapeutic studies, results support the null hypothesis that BMI does not predict overall intensity of the altered state, mystical experiences, perceptual changes, or emotional breakthroughs. There was weak evidence that lower BMI participants reported greater 'dread of ego dissolution,' but BMI did not meaningfully add to predictions beyond age, sex, and study. Mystical-type experiences and emotional breakthroughs strongly predicted well-being improvements, but BMI did not. These findings suggest body weight-adjusted dosing may be unnecessary, supporting fixed dosing to reduce practical and financial burdens on psychedelic therapy scalability.
Journal of eating disorders
September 30, 2024
Adele Lafrance, Meg J Spriggs, Natalie Gukasyan et al.
8 citations
Psychedelic medicine, including psychedelic-assisted therapy (PAT), may offer a valuable adjunct to existing treatments for eating disorders, particularly anorexia nervosa, by addressing underlying psychological and transpersonal factors and improving treatment engagement. Preliminary findings from multiple studies suggest promise, though risks remain. This commentary, informed by lived experience and authors' field experience, provides a rationale and multi-dimensional perspective for applying these models as they become more accessible in naturalistic, research, and clinical settings.