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Bruna Giribaldi

Perceptive Inc. (formerly Invicro LLC), Hammersmith Hospital, London (Wall, Demetriou, Ertl); Department of Metabolism, Digestion, and Reproduction (Wall, Ertl) and Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Faculty of Medicine (Wall, Ertl, Giribaldi, Roseman, Erritzoe, Nutt, Carhart-Harris), Imperial College London; Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, UK (Demetriou); Department of Neurology, University of California, San Francisco (Carhart-Harris).

19 papers in the library · 2,117 citations · publishing 2018-2025

Papers

Trial of Psilocybin versus Escitalopram for Depression

New England Journal of Medicine April 14, 2021 Robin Carhart‐Harris, Bruna Giribaldi, Rosalind Watts et al. 1,372 citations

In a selected group of patients, psilocybin did not show a significantly greater antidepressant effect than escitalopram based on depression scores at week 6. Secondary outcomes generally favored psilocybin, but these analyses were not corrected for multiple comparisons. The authors call for larger and longer trials to compare psilocybin with established antidepressants.

The hidden therapist: evidence for a central role of music in psychedelic therapy

Psychopharmacology February 1, 2018 Mendel Kaelen, Bruna Giribaldi, Jordan Raine et al. 274 citations

Music plays a central therapeutic role in psychedelic therapy with psilocybin for treatment-resistant depression. In interviews with 19 patients, music had both welcome influences—evoking meaningful emotion, mental imagery, guidance, openness, calm, and safety—and unwelcome influences, such as unpleasant emotion, imagery, and resistance. Patients' experience of the music correlated with mystical experiences and insightfulness. Critically, the nature of the music experience significantly predicted reductions in depression one week after psilocybin, whereas general drug intensity did not.

Therapeutic Alliance and Rapport Modulate Responses to Psilocybin Assisted Therapy for Depression

Frontiers in Pharmacology March 31, 2022 Roberta Murphy, Roberta Murphy, Hannes Kettner et al. 229 citations

In a trial comparing psilocybin-assisted therapy to escitalopram for moderate-to-severe depression, a stronger therapeutic alliance with the therapist predicted greater emotional breakthrough and mystical-type experiences during psilocybin sessions, and these experiences in turn predicted larger reductions in depression symptoms six weeks after treatment. Emotional breakthrough during the first session strengthened the alliance before the second session, while a weaker alliance before the second session directly predicted higher depression scores at the endpoint, independent of the acute psychedelic experience. The findings suggest the therapeutic relationship plays a key role in shaping both the quality of the psychedelic experience and clinical outcomes.

Effect of psilocybin versus escitalopram on depression symptom severity in patients with moderate-to-severe major depressive disorder: observational 6-month follow-up of a phase 2, double-blind, randomised, controlled trial

EClinicalMedicine September 23, 2024 David Erritzoe, Tommaso Barba, Kyle T Greenway et al. 46 citations

In a clinical trial, psilocybin therapy showed comparable effectiveness to a common SSRI antidepressant for treating depression, with both treatments leading to significant reductions in depressive symptoms over a follow-up period. The findings suggest psilocybin may offer a viable alternative to standard antidepressant medication, though the study's design and sample size limit the strength of conclusions.

Personality change in a trial of psilocybin therapy v. escitalopram treatment for depression.

Psychological medicine January 1, 2024 Brandon Weiss, Induni Ginige, Lu Shannon et al. 38 citations

In a trial comparing psilocybin therapy with the antidepressant escitalopram for moderate-to-severe major depressive disorder, both treatments led to personality changes in a direction consistent with improved mental health. Psilocybin was linked to decreases in neuroticism, introversion, disagreeableness, and impulsivity, and increases in absorption, conscientiousness, and openness at six weeks, with some changes lasting six months. Escitalopram was linked to decreases in neuroticism, disagreeableness, and impulsivity, and increases in openness at six weeks, with neuroticism remaining decreased at six months. No significant differences between the two treatments were observed, except that patients' pre-trial positive expectations for escitalopram moderated personality changes after that treatment, but not after psilocybin.

Unique Psychological Mechanisms Underlying Psilocybin Therapy Versus Escitalopram Treatment in the Treatment of Major Depressive Disorder

International Journal of Mental Health and Addiction March 7, 2024 Brandon Weiss, Leor Roseman, Bruna Giribaldi et al. 26 citations

Acute psychological experiences, particularly mystical experience and ego dissolution, partially account for how psilocybin therapy improves depression compared to escitalopram. In a phase 2 trial of patients with moderate-to-severe major depressive disorder, mystical experience and ego dissolution uniquely mediated the effect of treatment on depressive response. Higher levels of mystical experience, emotional breakthrough, and intense music-listening responses were also linked to greater antidepressant improvement. These findings suggest that acute psychological experiences play a causal mechanistic role in psilocybin therapy for depression.

Psychedelics and sexual functioning: a mixed-methods study

Scientific Reports February 7, 2024 Tommaso Barba, Hannes Kettner, Caterina Radu et al. 24 citations

Psychedelics may improve sexual functioning and satisfaction days or weeks after use, according to two studies. In a large naturalistic study, people who used psychedelics reported greater pleasure, communication during sex, and satisfaction with their partner and appearance. A controlled clinical trial comparing psilocybin therapy with the SSRI escitalopram for depression found that those given psilocybin reported positive changes in sexual functioning after treatment, while those given escitalopram did not. This is the first quantitative investigation of psychedelics' post-acute effects on sexual functioning, suggesting a potential benefit and a need for further research.

A critical evaluation of QIDS-SR-16 using data from a trial of psilocybin therapy versus escitalopram treatment for depression

Journal of Psychopharmacology April 25, 2023 Brandon Weiss, David Erritzoe, Bruna Giribaldi et al. 24 citations

A reanalysis of data from a trial comparing psilocybin therapy (PT) to escitalopram (ET) for major depressive disorder found that 14 of 16 outcome measures favored PT, but the QIDS-SR-16 did not. The QIDS-SR-16 showed higher variance, imprecision from compound items and sum-scoring, vague response options, and lack of focus on a core depression factor. When the trial data were examined at item, facet, and factor levels, results suggested PT was superior in reducing depressed mood, anhedonia, a core depression factor, and specific symptoms like sexual dysfunction. This raises concerns about relying on individual scales that miss depression's multidimensional structure.

Reduced Brain Responsiveness to Emotional Stimuli With Escitalopram But Not Psilocybin Therapy for Depression

American Journal of Psychiatry May 7, 2025 Matthew B Wall, Lysia Demetriou, Bruna Giribaldi et al. 16 citations

Psilocybin therapy greatly improved depressive symptoms but had only a small effect on how the brain responds to emotional stimuli. This contrasts with SSRIs, which often reduce emotional responsiveness alongside their antidepressant action. The findings suggest that psychedelic therapy may work through different neural mechanisms than conventional antidepressants.

Body mass index (BMI) does not predict responses to psilocybin

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.

A Bayesian Reanalysis of a Trial of Psilocybin Versus Escitalopram for Depression

Psychedelic Medicine October 28, 2022 Bruna Giribaldi, Sandeep M. Nayak, Bilal A. Bari et al. 15 citations

A Bayesian reanalysis of a trial comparing psilocybin (25 mg) to escitalopram (20 mg) over 6 weeks in 59 patients with major depressive disorder found that psilocybin outperformed escitalopram on three of four depression scales, though evidence was not uniformly clinically meaningful. Using skeptical priors that bias results toward zero, the analysis showed strong to extremely strong evidence favoring psilocybin on the BDI-1A, MADRS, and HAMD-17, while evidence on the primary outcome (QIDS SR-16) was indeterminate. For clinically meaningful superiority, evidence was moderate against it for the QIDS SR-16 but moderate to strong for the MADRS and HAMD-17. Psilocybin showed extremely strong evidence of noninferiority to escitalopram across all scales. The findings support further research on psilocybin's relative efficacy.

Decreased brain modularity after psilocybin therapy for depression.

Research Square May 20, 2021 Richard E. Daws, Christopher Timmerman, Bruna Giribaldi et al. 11 citations

Across two clinical trials, psilocybin therapy produced robust antidepressant effects that were linked to a decrease in brain network modularity measured by resting-state fMRI. In an open-label study of 16 adults with treatment-resistant depression, Beck Depression Inventory scores dropped sharply at one week and six months, and the reduction in network modularity one day after treatment correlated with clinical improvement at six months. In a double-blind randomized trial of 43 adults with major depressive disorder, the psilocybin arm showed superior antidepressant effects at two and six weeks compared with escitalopram, and improvements correlated with decreased modularity. These convergent findings suggest that psilocybin therapy may work by reducing the brain's network modularity.

Correction to: The hidden therapist: evidence for a central role of music in psychedelic therapy.

Psychopharmacology May 1, 2018 Mendel Kaelen, Bruna Giribaldi, Jordan Raine et al. 9 citations correction

Music plays a central role in psychedelic therapy by helping to guide and support the therapeutic process. The article synthesizes evidence that music can influence emotional states, facilitate psychological insights, and enhance the overall therapeutic outcome when combined with psychedelic substances. The authors argue that music acts as a "hidden therapist" by directing the trajectory of the psychedelic experience, promoting emotional release, and supporting the integration of the experience afterward. This suggests that careful selection and use of music is crucial for optimizing the therapeutic benefits of psychedelic therapy.

Reduced brain responsiveness to emotional stimuli with escitalopram but not psilocybin therapy for depression

medRxiv June 3, 2023 Matthew B. Wall, Lysia Demetriou, Bruna Giribaldi et al. 7 citations preprint

Psilocybin therapy for major depressive disorder may work through a different brain mechanism than the SSRI escitalopram. In a trial comparing two groups—one receiving two 25 mg psilocybin doses plus daily placebo, the other receiving daily escitalopram plus two inactive 1 mg psilocybin doses—brain responses to emotional faces were measured with fMRI before and after six weeks of treatment. The escitalopram group showed significantly reduced brain activity in response to fear, happy, and neutral faces, including a specific reduction in amygdala response to fear faces. The psilocybin group showed no such reduction and even a slight increase in brain responsiveness, despite large improvements in depressive symptoms. Reduced emotional responsiveness may be a biomarker of SSRIs' antidepressant action not shared by psilocybin therapy.

Enhanced meaning in life following psychedelic use: converging evidence from controlled and naturalistic studies

Frontiers in Psychology June 6, 2025 William Roseby, Hannes Kettner, Leor Roseman et al. 6 citations

Psychedelics like psilocybin strongly increase the sense that life has meaning, based on three different studies: a clinical trial for depression, a healthy volunteer study, and naturalistic retreats. The 'presence of meaning' rose substantially after a psychedelic experience, while the 'search for meaning' dropped only slightly. These meaning enhancements were moderately linked to improvements in mental health, such as greater wellbeing and reduced depression. Mystical, ego dissolution, and emotional breakthrough experiences were associated with increased meaning, though the strength varied by context. The evidence converges to show a robust, lasting positive effect of psychedelics on meaning in life, with context influencing outcomes.

The effects of psilocybin therapy versus escitalopram on cognitive bias: A secondary analysis of a randomized controlled trial

medRxiv March 21, 2025 Jessica S. Henry, Bruna Giribaldi, David Nutt et al. 2 citations preprint

In a randomized controlled trial of 59 patients with major depressive disorder, two high-dose psilocybin therapy sessions produced large increases in optimism and improvements in dysfunctional attitudes related to achievement, dependency, and self-control after six weeks. By contrast, a six-week daily course of escitalopram produced no change in optimism and only improved dysfunctional attitudes in the achievement domain. Psilocybin therapy was superior to escitalopram in remediating negative cognitive biases in depression.

The effects of psilocybin therapy versus escitalopram on cognitive bias: A secondary analysis of a randomized controlled trial.

European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology June 23, 2025 Jessica Henry, Bruna Giribaldi, David J Nutt et al. 1 citation

In patients with major depressive disorder, two high-dose psilocybin therapy sessions produced large increases in optimism and improvements in all three domains of dysfunctional attitudes (achievement, dependency, self-control) at six weeks, while a six-week daily course of escitalopram improved only the achievement domain and did not change optimism. Psilocybin also made patients more optimistic about desirable life events, whereas escitalopram reduced pessimism about negative life events. The findings suggest psilocybin therapy is superior to escitalopram for remediating negative cognitive biases in depression.

A Bayesian Reanalysis of a Trial of Psilocybin versus Escitalopram for Depression

June 30, 2022 Sandeep M. Nayak, Bilal A. Bari, David B. Yaden et al. 1 citation preprint

A Bayesian reanalysis of a trial comparing psilocybin (COMP360) to escitalopram for major depressive disorder found that psilocybin outperformed escitalopram, but not by a clinically meaningful amount. The analysis also found extremely strong evidence that psilocybin is non-inferior to escitalopram. Evidence for psilocybin's superiority varied by depression scale: indeterminate for one, strong for two, and extremely strong for another. For a clinically meaningful difference, evidence was moderate against it on one scale, indeterminate on two, and moderate supporting it on one. These results provide a more nuanced interpretation and support further research.