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Journal articleBonnelle V, Feilding A, Rosas FE, et al., 2024,
Autonomic nervous system activity correlates with peak experiences induced by DMT and predicts increases in well-being.
, J Psychopharmacol, Vol: 38, Pages: 887-896BACKGROUND: Non-ordinary states of consciousness induced by psychedelics can be accompanied by so-called "peak experiences," characterized at the emotional level by their intensity and positive valence. These experiences are strong predictors of positive outcomes following psychedelic-assisted therapy, and it is therefore important to better understand their biology. Despite growing evidence that the autonomic nervous system (ANS) plays an important role in mediating emotional experiences, its involvement in the psychedelic experience is poorly understood. The aim of this study was to investigate to what extent changes in the relative influence of the sympathetic (SNS) and parasympathetic nervous systems (PNS) over cardiac activity may reflect the subjective experience induced by the short-acting psychedelic N,N-Dimethyltryptamine (DMT). METHODS: We derived measures of SNS and PNS activity from the electrocardiograms of 17 participants (11 males, mean age = 33.8 years, SD = 8.3) while they received either DMT or placebo. RESULTS: Results show that the joint influence of SNS and PNS ("sympathovagal coactivation") over cardiac activity was positively related to participants' ratings of "Spiritual Experience" and "Insightfulness" during the DMT experience, while also being related to improved well-being scores 2 weeks after the session. In addition, we found that the state of balance between the two ANS branches ("sympathovagal balance") before DMT injection predicted scores of "Insightfulness" during the DMT experience, as well as subsequent sympathovagal coactivation. CONCLUSION: These findings demonstrate the involvement of the ANS in psychedelic-induced peak experiences and may pave the way to the development of biofeedback-based tools to enhance psychedelic therapy.
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Journal articleAngyus M, Osborn S, Haijen E, et al., 2024,
Validation of the imperial psychedelic predictor scale.
, Psychol Med, Pages: 1-9BACKGROUND: Access to psychedelic drugs is liberalizing, yet responses are highly unpredictable. It is therefore imperative that we improve our ability to predict the nature of the acute psychedelic experience to improve safety and optimize potential therapeutic outcomes. This study sought to validate the 'Imperial Psychedelic Predictor Scale' (IPPS), a short, widely applicable, prospective measure intended to be predictive of salient dimensions of the psychedelic experience. METHODS: Using four independent datasets in which the IPPS was completed prospectively - two online surveys of 'naturalistic' use (N = 741, N = 836) and two controlled administration datasets (N = 30, N = 28) - we conducted factor analysis, regression, and correlation analyses to assess the construct, predictive, and convergent validity of the IPPS. RESULTS: Our approach produced a 9-item scale with good internal consistency (Cronbach's α = 0.8) containing three factors: set, rapport, and intention. The IPPS was significantly predictive of 'mystical', 'challenging', and 'emotional breakthrough' experiences. In a controlled administration dataset (N = 28), multiple regression found set and rapport explaining 40% of variance in mystical experience, and simple regression found set explained 16% of variance in challenging experience. In another (N = 30), rapport was related to emotional breakthrough explaining 9% of variance. CONCLUSIONS: Together, these data suggest that the IPPS is predictive of relevant acute features of the psychedelic experience in a broad range of contexts. We hope that this brief 9-item scale will be widely adopted for improved knowledge of psychedelic preparedness in controlled settings and beyond.
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Journal articleMurphy RJ, Sumner RL, Godfrey K, et al., 2024,
Multimodal creativity assessments following acute and sustained microdosing of lysergic acid diethylamide.
, Psychopharmacology (Berl)INTRODUCTION: Enhanced creativity is often cited as an effect of microdosing (taking repeated low doses of a psychedelic drug). There have been recent efforts to validate the reported effects of microdosing, however creativity remains a difficult construct to quantify. OBJECTIVES: The current study aimed to assess microdosing's effects on creativity using a multimodal battery of tests as part of a randomised controlled trial of microdosing lysergic acid diethylamide (LSD). METHODS: Eighty healthy adult males were given 10 µg doses of LSD or placebo every third day for six weeks (14 total doses). Creativity tasks were administered at a drug-free baseline session, at a first dosing session during the acute phase of the drug's effects, and in a drug-free final session following the six-week microdosing regimen. Creativity tasks were the Alternate Uses Test (AUT), Remote Associates Task (RAT), Consensual Assessment Technique (CAT), and an Everyday Problem-Solving Questionnaire (EPSQ). RESULTS: No effect of drug by time was found on the AUT, RAT, CAT, or EPSQ. Baseline vocabulary skill had a significant effect on AUT and RAT scores. CONCLUSIONS: Despite participants reporting feeling more creative on dose days, objective measurement found no acute or durable effects of the microdosing protocol on creativity. Possible explanations of these null findings are that laboratory testing conditions may negatively affect ability to detect naturalistic differences in creative performance, the tests available do not capture the facets of creativity that are anecdotally affected by microdosing, or that reported enhancements of creativity are placebo effects.
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Journal articleKettner H, Roseman L, Gazzaley A, et al., 2024,
Effects of Psychedelics in Older Adults: A Prospective Cohort Study.
, Am J Geriatr Psychiatry, Vol: 32, Pages: 1047-1059OBJECTIVE: Affective symptoms such as anxiety, low mood, and loneliness are prevalent and highly debilitating symptoms among older adults (OA). Serotonergic psychedelics are currently investigated as novel interventions for affective disorders, yet little is known regarding their effects in OA. We investigated the mental health effects and psychological mechanisms of guided psychedelic group experiences in OA and a matched sample of younger adults (YA). METHODS: Using a prospective observational cohort design, we identified 62 OA (age ≥60 years) and 62 matched YA who completed surveys two weeks before, a day, two weeks, four weeks, and six months after a psychedelic group session. Mixed linear regression analyses were used to investigate longitudinal well-being changes, as well as baseline, acute, and post-acute predictors of change. RESULTS: OA showed post-psychedelic well-being improvements similar to matched YA. Among baseline predictors, presence of a lifetime psychiatric diagnosis was associated with greater well-being increases in OA (B = 6.72, p = .016 at the four-week key-endpoint). Compared to YA, acute subjective psychedelic effects were less intense in OA and did not significantly predict prospective well-being changes. However, relational experiences before and after psychedelic sessions emerged as predictors in OA (r(36) = .37,p = 0.025). CONCLUSIONS: Guided psychedelic group sessions enhance well-being in OA in line with prior naturalistic and controlled studies in YA. Interestingly, acute psychedelic effects in OA are attenuated and less predictive of well-being improvements, with relational experiences related to the group setting playing a more prominent role. Our present findings call for further research on the effects of psychedelics in OA.
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Journal articleDavid E, Barba T, Robin C-H, 2024,
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, ISSN: 2589-5370Background Psilocybin therapy (PT) produces rapid and persistent antidepressant effects in major depressive disorder (MDD). However, the long-term effects of PT have never been compared with gold-standard treatments for MDD such as pharmacotherapy or psychotherapy alone or in combination. Methods This is a 6-month follow-up study of a phase 2, double-blind, randomised, controlled trial involving patients with moderate-to-severe MDD. Participants were recruited from a hospital in the UK. Inclusion criteria: major depressive disorder (DSM-IV), moderate to severe depression (HAM-D ≥ 17), no MRI or SSRI contraindications, confirmed diagnosis by a GP or mental healthcare professional, aged 18-80, both genders, and competent in English. Patients were randomly assigned (1:1) to receive either two 25 mg doses of the psychedelic drug psilocybin administered orally combined with psychological support (‘psilocybin therapy’ or PT) and book-ended by further support or a 6-week course of the selective serotonin reuptake inhibitor (SSRI) escitalopram (administered daily at 10 mg for three weeks and 20 mg for the subsequent three weeks) plus matched psychological support (‘escitalopram treatment’ or ET). The primary outcome measure was change from baseline in the score on the 16-item Quick Inventory of Depressive Symptomatology–Self-Report (QIDS-SR-16) at week 6, which has been reported previously. Herein, we present results at the 6-month follow-up time point. Measures of social functioning, connectedness, and meaning in life constituted the study’s secondary outcomes during follow-up. Safety in the follow-up period was not assessed. This trial is registered at ClinicalTrials.gov, NCT03429075.Findings Between January 15th, 2019 and March 20th , 2020, 59 patients were enrolled and 30 (11 females (37%) and 19 males (63%)) were assigned to the psilocybin group and 29 (9 females (31%) and 20 males (69%)) to the escitalopram group. 25 participants
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Journal articleBrouwer A, Carhart-Harris RL, Raison CL, 2024,
Psychotomimetic compensation versus sensitization.
, Pharmacol Res Perspect, Vol: 12It is a paradox that psychotomimetic drugs can relieve symptoms that increase risk of and cooccur with psychosis, such as attention and motivational deficits (e.g., amphetamines), pain (e.g., cannabis) and symptoms of depression (e.g., psychedelics, dissociatives). We introduce the ideas of psychotomimetic compensation and psychotomimetic sensitization to explain this paradox. Psychotomimetic compensation refers to a short-term stressor or drug-induced compensation against stress that is facilitated by engagement of neurotransmitter/modulator systems (endocannabinoid, serotonergic, glutamatergic and dopaminergic) that mediate the effects of common psychotomimetic drugs. Psychotomimetic sensitization occurs after repeated exposure to stress and/or drugs and is evidenced by the gradual intensification and increase of psychotic-like experiences over time. Theoretical and practical implications of this model are discussed.
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Journal articleSiegel JS, Subramanian S, Perry D, et al., 2024,
Psilocybin desynchronizes the human brain.
, Nature, Vol: 632, Pages: 131-138A single dose of psilocybin, a psychedelic that acutely causes distortions of space-time perception and ego dissolution, produces rapid and persistent therapeutic effects in human clinical trials1-4. In animal models, psilocybin induces neuroplasticity in cortex and hippocampus5-8. It remains unclear how human brain network changes relate to subjective and lasting effects of psychedelics. Here we tracked individual-specific brain changes with longitudinal precision functional mapping (roughly 18 magnetic resonance imaging visits per participant). Healthy adults were tracked before, during and for 3 weeks after high-dose psilocybin (25 mg) and methylphenidate (40 mg), and brought back for an additional psilocybin dose 6-12 months later. Psilocybin massively disrupted functional connectivity (FC) in cortex and subcortex, acutely causing more than threefold greater change than methylphenidate. These FC changes were driven by brain desynchronization across spatial scales (areal, global), which dissolved network distinctions by reducing correlations within and anticorrelations between networks. Psilocybin-driven FC changes were strongest in the default mode network, which is connected to the anterior hippocampus and is thought to create our sense of space, time and self. Individual differences in FC changes were strongly linked to the subjective psychedelic experience. Performing a perceptual task reduced psilocybin-driven FC changes. Psilocybin caused persistent decrease in FC between the anterior hippocampus and default mode network, lasting for weeks. Persistent reduction of hippocampal-default mode network connectivity may represent a neuroanatomical and mechanistic correlate of the proplasticity and therapeutic effects of psychedelics.
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Journal articleLynskey MT, Thurgur H, Athanasiou-Fragkouli A, et al., 2024,
Suicidal Ideation in Medicinal Cannabis Patients: A 12-Month Prospective Study.
, Arch Suicide Res, Pages: 1-15OBJECTIVE: To document the prevalence and correlates of suicidal ideation (SI) among individuals seeking cannabis-based medicinal products (CBMPs); to test whether SI declines or intensifies after three months of CBMP treatment and to document 12-month trajectories of depression in those reporting SI and other patients. METHOD: Observational data were available for 3781 patients at entry to treatment, 2112 at three months and 777 for 12 months. Self-reported depressed mood and SI were assessed using items from the PHQ-9. Additional data included sociodemographic characteristics and self-reported well-being. RESULTS: 25% of the sample reported SI at treatment entry and those with SI had higher levels of depressed mood (mean = 17.4 vs. 11.3; F(1,3533) = 716.5, p < .001) and disturbed sleep (mean = 13.8 vs. 12.2, F(1,3533) = 125.9, p < .001), poorer general health (mean = 43.6 vs. 52.2, F(1,3533) = 118.3, p < .001) and lower quality of life (mean = 0.44 vs. 0.56 (F(1,3533) = 118.3, p < .001). The prevalence of SI reduced from 23.6% to 17.6% (z = 6.5, p < .001) at 3 months. Twelve-month follow-up indicated a substantial reduction in depressed mood with this reduction being more pronounced in those reporting SI (mean (baseline) = 17.7 vs. mean (12 months) = 10.3) than in other patients (mean (baseline) = 11.1 vs. mean (12 months) = 7.0). CONCLUSIONS: SI is common among individuals seeking CBMPs to treat a range of chronic conditions and is associated with higher levels of depressed mood and poorer quality of life. Treatment with CBMPs reduced the prevalence and intensity of suicidal ideation.
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Journal articlede la Salle S, Kettner H, Thibault Lévesque J, et al., 2024,
Longitudinal experiences of Canadians receiving compassionate access to psilocybin-assisted psychotherapy.
, Sci Rep, Vol: 14Recent clinical trials have found that the serotonergic psychedelic psilocybin effectively alleviates anxiodepressive symptoms in patients with life-threatening illnesses when given in a supportive environment. These outcomes prompted Canada to establish legal pathways for therapeutic access to psilocybin, coupled with psychological support. Despite over one-hundred Canadians receiving compassionate access since 2020, there has been little examination of these 'real-world' patients. We conducted a prospective longitudinal survey which focused on Canadians who were granted Section 56 exemptions for legal psilocybin-assisted psychotherapy. Surveys assessing various symptom dimensions were conducted at baseline, two weeks following the session (endpoint), and optionally one day post-session. Participant characteristics were examined using descriptive statistics, and paired sample t-tests were used to quantify changes from baseline to the two-week post-treatment endpoint. Eight participants with Section 56 exemptions (four females, Mage = 52.3 years), all with cancer diagnoses, fully completed baseline and endpoint surveys. Significant improvements in anxiety and depression symptoms, pain, fear of COVID-19, quality of life, and spiritual well-being were observed. Attitudes towards death, medical assistance in dying, and desire for hastened death remained unchanged. While most participants found the psilocybin sessions highly meaningful, if challenging, one reported a substantial decrease in well-being due to the experience. These preliminary data are amongst the first to suggest that psilocybin-assisted psychotherapy can produce psychiatric benefits in real-world patients akin to those observed in clinical trials. Limited enrollment and individual reports of negative experiences indicate the need for formal real-world evaluation programs to surveil the ongoing expansion of legal access to psychedelics.
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Journal articleThurgur H, Lynskey M, Schlag AK, et al., 2024,
Authors' response to letter 'On the use of open-label studies for the evaluation of cannabis-based products for the treatment of long-COVID'.
, Br J Clin Pharmacol
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