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28 Jan 2019

2018 Psilocybin science roundup

by Roderick

The following are excerpts from studies completed in 2018 that provide information or context on the medical applications of psilocybin. They range from the perceived effects of various substances to intensive studies of brain chemistry and physiology. They stand on the shoulders of the psychedelic studies that preceded them, and pave the way for future investigations to elucidate the full nature of psilocybin’s power.

As a nod to those true pioneers and patrons of the research that normalizes and legitimizes the therapeutic and medicinal use of psychedelics, we’ve highlighted an individual and institution specifically for their contributions in 2018. As you will see below, these names appear constantly throughout this list of innovative research published last year. They will likely continue to be at the forefront of research in this domain for years to come.

Articles marked with a ⭐ indicate work involving 2018 star researcher Robin Carhart-Harris.

Articles marked with a 🏤 indicate work done at, or in collaboration with, 2018 star institution Johns Hopkins University.

The top studies and findings of 2018 on psilocybin therapy and research

"Microdosing Psychedelics: Personality, mental health, and creativity differences in microdosers." Anderson et al.

Microdosing psychedelics—the regular consumption of small amounts of psychedelic substances such as LSD or psilocybin—is a growing trend in popular culture. Current and former microdosers scored lower on self-reported measures of dysfunctional attitudes and negative emotionality, while scoring higher on wisdom, open mindedness, and creativity when compared to non-microdosing controls. These findings provide promising initial evidence that warrants controlled experimental research to directly test safety and clinical efficacy. As microdoses are easier to administer than full-doses, this new paradigm has the exciting potential to shape future psychedelic research.

🏤 "Psilocybin-occasioned mystical-type experience in combination with meditation and other spiritual practices produces enduring positive changes in psychological functioning and in trait measures of prosocial attitudes and behaviors." Griffiths et al.

Psilocybin can occasion mystical-type experiences with subjective increases in perceived well-being. However, little research has examined enduring changes in traits. This study administered psilocybin to participants who undertook a program of meditation/spiritual practices. Compared with a low-dose, high-dose psilocybin produced greater acute and persisting effects, showing significant positive changes on measures of interpersonal closeness, gratitude, sense of life meaning/purpose, forgiveness, daily spiritual experiences, and religious faith and coping.

⭐ "Psilocybin with psychological support for treatment-resistant depression: six-month follow-up." Carhart-Harris et al.

This study focused on patients with severe, unipolar, treatment-resistant major depression (TRD). They received two doses of psilocybin seven days apart in a supportive setting, and their depressive symptoms were assessed for up to 6 months after psilocybin treatment. Marked reductions were observed for the first five weeks post-treatment; over half the patients met the criteria for either response or remission of their TRD at week five. Results remained positive at three and six months. No patients sought conventional antidepressant treatment within five weeks of psilocybin.

⭐ "Psilocybin with psychological support improves emotional face recognition in treatment-resistant depression." Stroud et al.

The objective of this study is to investigate whether psilocybin, recently shown to rapidly improve mood in treatment-resistant depression (TRD), alters patients’ emotional processing biases. Before psilocybin, TRD patients were slower at recognising facial emotions compared with healthy controls. After psilocybin therapy, this difference between patients and controls was made non-significant. Emotion recognition was also faster after psilocybin treatment in patients, and this change was significantly correlated with a reduction in anhedonia (the inability to feel pleasure).

🏤 "Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: similarities and differences in subjective experiences." Carbonaro et al.

This study compared subjective, behavioral, and physiological effects of psilocybin and dextromethorphan (DXM) under conditions that minimized expectancy effects. High doses of both drugs produced similar increases in ratings of peak overall drug strength, with similar times to maximal effect and time-course. However, the high dose of psilocybin produced significantly greater and more diverse visual effects than DXM, including greater movement and more frequent, brighter, distinctive, and complex images and visions. Compared to DXM, psilocybin also produced significantly greater mystical-type and psychologically insightful experiences and greater absorption in music. In contrast, DXM produced larger effects than psilocybin on measures of disembodiment, nausea/vomiting, and lightheadedness.

🏤 "Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: effects on cognition." Barrett et al.

This study compares the neuropsychological effects of multiple doses of the classic psychedelic psilocybin with the effects of a single high dose of the dissociative hallucinogen dextromethorphan (DXM). Dose-dependent effects of psilocybin were observed on psychomotor performance, working memory, episodic memory, associative learning, and visual perception. Effects of DXM on psychomotor performance, visual perception, and associative learning were in the range of effects of a moderate to high dose of psilocybin. Evidence of delirium or global cognitive impairment was not observed with either psilocybin or DXM. Psilocybin had greater effects than DXM on working memory. DXM had greater effects than all psilocybin doses on balance, episodic memory, response inhibition, and executive control.

⭐ "Quality of acute psychedelic experience predicts therapeutic efficacy of psilocybin for treatment-resistant depression." Roseman et al.

It is a basic principle of the ‘psychedelic’ treatment model that the quality of the acute experience mediates long-term improvements in mental health. This was put to the test using data from a clinical trial assessing psilocybin for treatment-resistant depression (TRD). The occurrence of mystical experiences and ‘ego death’, or the anxiety surrounding it, significantly correlated with long-term positive outcomes when compared to baseline. Furthermore, the correlation of mystical experiences with improvement at five weeks was specific compared to the recorded magnitude of perceptual effects.

⭐ "Altered trajectories in the dynamical repertoire of functional network states under psilocybin." Lord et al.

This study investigated changes in the brain's dynamical repertoire in an fMRI dataset of healthy participants intravenously injected with psilocybin. Researchers found that a state closely corresponding to the fronto-parietal control system was strongly destabilized in the psychedelic state, while transitions toward a globally synchronized state were enhanced. These differences suggest that psychedelics create a bias toward a global mode of functional integration at the expense of locally segregated activity in specific networks.

"High dose psilocybin is associated with positive subjective effects in healthy volunteers." Nicholas et al.

This study investigated the relationship between escalating higher doses of psilocybin and the potential for positive subjective effects. There was a significant dose-related response in total score, specifically in the transcendence of time and space, but not in the rate of a complete mystical experience. 30 days after completion of the last dose, self-reported moderate increases in a sense of well-being or life satisfaction on average persisted. High doses of psilocybin elicited subjective effects at least as strong as the lower doses and resulted in positive persisting subjective effects 30 days after, indicating that a complete mystical experience was not a prerequisite for positive outcomes.

⭐ "Effects of psilocybin therapy on personality structure." Erritzoe et al.

This study explores whether psilocybin with psychological support modulates personality parameters in patients suffering from treatment-resistant depression (TRD). Neuroticism scores significantly decreased while extraversion increased following psilocybin therapy. Both were predicted by the degree of insightfulness experienced during the psilocybin session. Openness scores also significantly increased following psilocybin therapy. The changes were consistent with reports of personality change in relation to conventional antidepressant treatment, although the pronounced increases in extraversion and openness might constitute an effect more specific to psychedelic therapy.

⭐ "More realistic forecasting of future life events after psilocybin for treatment-resistant depression." Lyons and Carhart-Harris.

This study aimed to investigate the effects of an intervention involving psilocybin on pessimism biases in patients with treatment-resistant depression (TRD). Patients showed a significant pessimism bias before psilocybin therapy, which was related to the severity of their depressive symptoms. After psilocybin treatment, this bias was significantly decreased and depressive symptoms were greatly improved. Importantly, post psilocybin treatment, patients became significantly more accurate at predicting the occurrence of future life events.

"Exploring the effect of microdosing psychedelics on creativity in an open-label natural setting." Prochazkova et al.

Microdoses of psychedelic substances allegedly have multiple beneficial effects including creativity and problem-solving performance, potentially mediated through promoting cognitive flexibility. The aim was to quantitatively explore the cognitive-enhancing potential of microdosing psychedelics in healthy adults. The researchers found that both convergent and divergent thinking performance was improved after a non-blinded microdose. While this study provides quantitative support for the cognitive-enhancing properties of microdosing psychedelics, future research is needed to confirm these preliminary findings in more rigorous placebo-controlled study designs.

Read the full Psillow review of this microdosing article here

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Anderson, Thomas, et al. "Microdosing Psychedelics: Personality, mental health, and creativity differences in microdosers." Psychopharmacology (2018): 1-10.

Griffiths, Roland R., et al. "Psilocybin-occasioned mystical-type experience in combination with meditation and other spiritual practices produces enduring positive changes in psychological functioning and in trait measures of prosocial attitudes and behaviors." Journal of Psychopharmacology 32.1 (2018): 49-69.

Stroud, J. B., et al. "Psilocybin with psychological support improves emotional face recognition in treatment-resistant depression." Psychopharmacology 235.2 (2018): 459-466.

Carhart-Harris, R. L., et al. "Psilocybin with psychological support for treatment-resistant depression: six-month follow-up." Psychopharmacology 235.2 (2018): 399-408.

Carbonaro, Theresa M., et al. "Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: similarities and differences in subjective experiences." Psychopharmacology 235.2 (2018): 521-534.

Barrett, Frederick S., et al. "Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: effects on cognition." Psychopharmacology 235.10 (2018): 2915-2927.

Roseman, Leor, David J. Nutt, and Robin L. Carhart-Harris. "Quality of acute psychedelic experience predicts therapeutic efficacy of psilocybin for treatment-resistant depression." Frontiers in pharmacology 8 (2018): 974.

Lord, Louis-David, et al. "Altered trajectories in the dynamical repertoire of functional network states under psilocybin." bioRxiv (2018): 376491.

Nicholas, Christopher R., et al. "High dose psilocybin is associated with positive subjective effects in healthy volunteers." Journal of Psychopharmacology 32.7 (2018): 770-778.

Erritzoe, D., et al. "Effects of psilocybin therapy on personality structure." Acta Psychiatrica Scandinavica (2018).

Lyons, Taylor, and Robin Lester Carhart-Harris. "More realistic forecasting of future life events after psilocybin for treatment-resistant depression." Frontiers in psychology 9 (2018).

Prochazkova, Luisa, et al. "Exploring the effect of microdosing psychedelics on creativity in an open-label natural setting." Psychopharmacology 235.12 (2018): 3401-3413.

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