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Predicting therapeutic response to oral ketamine for chronic suicidal ideation: a Bayesian network for clinical decision support

November 30, 2021 / Depressive Disorders, Ketamine, Papers / Leave a Comment / By / , , , , , , , , , ,

Abstract

Background: The glutamatergic modulator ketamine has been shown to result in rapid reductions in both suicidal ideation (SI) and depressive symptoms in clinical trials. There is a practical need for identification of pre-treatment predictors of ketamine response. Previous studies indicate links between treatment response and body mass index (BMI), depression symptoms and previous suicide attempts. Our aim was to explore the use of clinical and demographic factors to predict response to serial doses of oral ketamine for chronic suicidal ideation.

Methods: Thirty-two participants completed the Oral Ketamine Trial on Suicidality (OKTOS). Data for the current study were drawn from pre-treatment and follow-up time-points of OKTOS. Only clinical and sociodemographic variables were included in this analysis. Data were used to create a proof of concept Bayesian network (BN) model of variables predicting prolonged response to oral ketamine, as defined by the Beck Scale for Suicide Ideation (BSS).

Results: The network of potential predictors of response was evaluated using receiver operating characteristic (ROC) curve analyses. A combination of nine demographic and clinical variables predicted prolonged ketamine response, with strong contributions from BMI, Social and Occupational Functioning Assessment Scale (SOFAS), Montgomery-Asberg Depression Rating Scale (MADRS), number of suicide attempts, employment status and age. We evaluated and optimised the proposed network to increase the area under the ROC curve (AUC). The performance evaluation demonstrated that the BN predicted prolonged ketamine response with 97% accuracy, and AUC = 0.87.

Conclusions: At present, validated tools to facilitate risk assessment are infrequently used in psychiatric practice. Pre-treatment assessment of individuals’ likelihood of response to oral ketamine for chronic suicidal ideation could be beneficial in making more informed decisions about likelihood of success for this treatment course. Clinical trials registration number ACTRN12618001412224, retrospectively registered 23/8/2018.

Beaudequin, D., Can, A. T., Dutton, M., Jones, M., Gallay, C., Schwenn, P., Yang, C., Forsyth, G., Simcock, G., Hermens, D. F., & Lagopoulos, J. (2020). Predicting therapeutic response to oral ketamine for chronic suicidal ideation: a Bayesian network for clinical decision support. BMC psychiatry, 20(1), 519. https://doi.org/10.1186/s12888-020-02925-1

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Toxicokinetics and Toxicodynamics of Ayahuasca Alkaloids N, N-Dimethyltryptamine (DMT), Harmine, Harmaline and Tetrahydroharmine: Clinical and Forensic Impact

November 30, 2021 / Ayahuasca, DMT, Papers, Psychology / Leave a Comment / By / , , , ,

Abstract

Ayahuasca is a hallucinogenic botanical beverage originally used by indigenous Amazonian tribes in religious ceremonies and therapeutic practices. While ethnobotanical surveys still indicate its spiritual and medicinal uses, consumption of ayahuasca has been progressively related with a recreational purpose, particularly in Western societies. The ayahuasca aqueous concoction is typically prepared from the leaves of the N,N-dimethyltryptamine (DMT)-containing Psychotria viridis, and the stem and bark of Banisteriopsis caapi, the plant source of harmala alkaloids. Herein, the toxicokinetics and toxicodynamics of the psychoactive DMT and harmala alkaloids harmine, harmaline and tetrahydroharmine, are comprehensively covered, particularly emphasizing the psychological, physiological, and toxic effects deriving from their concomitant intake. Potential therapeutic utility, particularly in mental and psychiatric disorders, and forensic aspects of DMT and ayahuasca are also reviewed and discussed. Following administration of ayahuasca, DMT is rapidly absorbed and distributed. Harmala alkaloids act as potent inhibitors of monoamine oxidase A (MAO-A), preventing extensive first-pass degradation of DMT into 3-indole-acetic acid (3-IAA), and enabling sufficient amounts of DMT to reach the brain. DMT has affinity for a variety of serotonergic and non-serotonergic receptors, though its psychotropic effects are mainly related with the activation of serotonin receptors type 2A (5-HT2A). Mildly to rarely severe psychedelic adverse effects are reported for ayahuasca or its alkaloids individually, but abuse does not lead to dependence or tolerance. For a long time, the evidence has pointed to potential psychotherapeutic benefits in the treatment of depression, anxiety, and substance abuse disorders; and although misuse of ayahuasca has been diverting attention away from such clinical potential, research onto its therapeutic effects has now strongly resurged.

Brito-da-Costa, A. M., Dias-da-Silva, D., Gomes, N., Dinis-Oliveira, R. J., & Madureira-Carvalho, Á. (2020). Toxicokinetics and Toxicodynamics of Ayahuasca Alkaloids N,N-Dimethyltryptamine (DMT), Harmine, Harmaline and Tetrahydroharmine: Clinical and Forensic Impact. Pharmaceuticals (Basel, Switzerland), 13(11), 334. https://doi.org/10.3390/ph13110334

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A mechanistic model of the neural entropy increase elicited by psychedelic drugs

November 26, 2021 / Neuroscience, Papers / Leave a Comment / By / , , , , , ,

Abstract

Psychedelic drugs, including lysergic acid diethylamide and other agonists of the serotonin 2A receptor (5HT2A-R), induce drastic changes in subjective experience, and provide a unique opportunity to study the neurobiological basis of consciousness. One of the most notable neurophysiological signatures of psychedelics, increased entropy in spontaneous neural activity, is thought to be of relevance to the psychedelic experience, mediating both acute alterations in consciousness and long-term effects. However, no clear mechanistic explanation for this entropy increase has been put forward so far. We sought to do this here by building upon a recent whole-brain model of serotonergic neuromodulation, to study the entropic effects of 5HT2A-R activation. Our results reproduce the overall entropy increase observed in previous experiments in vivo, providing the first model-based explanation for this phenomenon. We also found that entropy changes were not uniform across the brain: entropy increased in some regions and decreased in others, suggesting a topographical reconfiguration mediated by 5HT2A-R activation. Interestingly, at the whole-brain level, this reconfiguration was not well explained by 5HT2A-R density, but related closely to the topological properties of the brain’s anatomical connectivity. These results help us understand the mechanisms underlying the psychedelic state and, more generally, the pharmacological modulation of whole-brain activity.

Herzog, R., Mediano, P., Rosas, F. E., Carhart-Harris, R., Perl, Y. S., Tagliazucchi, E., & Cofre, R. (2020). A mechanistic model of the neural entropy increase elicited by psychedelic drugs. Scientific reports, 10(1), 17725. https://doi.org/10.1038/s41598-020-74060-6

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Pharmacokinetics and Pharmacodynamics of Lysergic Acid Diethylamide Microdoses in Healthy Participants

November 26, 2021 / LSD, Microdosing, Papers / Leave a Comment / By / , , , , , , , , ,

Abstract

“Microdoses” of lysergic acid diethylamide (LSD) are used recreationally to enhance mood and cognition. Increasing interest has also been seen in developing LSD into a medication. Therefore, we performed a pharmacokinetic-pharmacodynamic study using very low doses of LSD. Single doses of LSD base (5, 10, and 20 µg) and placebo were administered in a double-blind, randomized, placebo-controlled crossover study in 23 healthy participants. Test days were separated by at least 5 days. Plasma levels of LSD and subjective effects were assessed up to 6 hours after administration. Pharmacokinetic parameters were determined using compartmental modeling. Concentration-subjective effect relationships were described using pharmacokinetic-pharmacodynamic modeling. Mean (95% confidence interval) maximal LSD concentrations were 151 pg/mL (127-181), 279 pg/mL (243-320), and 500 pg/mL (413-607) after 5, 10, and 20 µg LSD administration, respectively. Maximal concentrations were reached after 1.1 hours. The mean elimination half-life was 2.7 hours (1.5-6.2). The 5 µg dose of LSD elicited no significant acute subjective effects. The 10 µg dose of LSD significantly increased ratings of “under the influence” and “good drug effect” compared with placebo. These effects began an average of 1.1 hours after 10 µg LSD administration, peaked at 2.5 hours, and ended at 5.1 hours. The 20 µg dose of LSD significantly increased ratings of “under the influence,” “good drug effects,” and “bad drug effects.” LSD concentrations dose-proportionally increased at doses as low as 5-20 µg and decreased with a half-life of 3 hours. The threshold dose of LSD base for psychotropic effects was 10 µg.

Holze, F., Liechti, M. E., Hutten, N., Mason, N. L., Dolder, P. C., Theunissen, E. L., Duthaler, U., Feilding, A., Ramaekers, J. G., & Kuypers, K. (2021). Pharmacokinetics and Pharmacodynamics of Lysergic Acid Diethylamide Microdoses in Healthy Participants. Clinical pharmacology and therapeutics, 109(3), 658–666. https://doi.org/10.1002/cpt.2057

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Making “bad trips” good: How users of psychedelics narratively transform challenging trips into valuable experiences

November 26, 2021 / Papers, Psychology / Leave a Comment / By / , ,

Abstract

Background: We study the significance of stories about bad trips among users of psychedelics. Drawing on narrative theory, we describe the characteristics of such stories and explore the work they do.

Methods: In-depth qualitative interviews with 50 Norwegian users of psychedelics.

Results: Almost all participants had frightening experiences when using psychedelics and many described these as bad trips. The key feature of a bad trip was a feeling of losing oneself or going crazy, or ego dissolution. Most users said that these experiences could be avoided by following certain rules, based on tacit knowledge in the subcultures of users. Possessing such knowledge was part of symbolic boundary work that distinguished between drug culture insiders and outsiders. Some also rejected the validity of the term bad trip altogether, arguing that such experiences reflected the lack of such competence. Finally, and most importantly, most participants argued that unpleasant experiences during bad trips had been beneficial and had sometimes given them deep existential and life-altering insights.

Conclusion: Bad trip experiences are common among users of psychedelics. Such experiences are often transformed into valuable experiences through storytelling. Bad trip narratives may be a potent coping mechanism for users of psychedelics in non-controlled environments, enabling them to make sense of frightening experiences and integrate these into their life stories. Such narrative sense-making, or narrative work, facilitates the continued use of psychedelics, even after unpleasant experiences with the drugs.

Gashi, L., Sandberg, S., & Pedersen, W. (2021). Making “bad trips” good: How users of psychedelics narratively transform challenging trips into valuable experiences. The International journal on drug policy, 87, 102997. https://doi.org/10.1016/j.drugpo.2020.102997

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Mood and cognition after administration of low LSD doses in healthy volunteers: A placebo controlled dose-effect finding study

November 26, 2021 / LSD, Microdosing, Papers, Psychology / Leave a Comment / By / , , , , , , , ,

Abstract

There is a popular interest in microdosing with psychedelics such as LSD. This practice of using one-tenth of a full psychedelic dose according to a specific dosing schedule, anecdotally enhances mood and performance. Nonetheless, controlled research on the efficacy of microdosing is scarce. The main objective of the present dose-finding study was to determine the minimal dose of LSD needed to affect mood and cognition. A placebo-controlled within-subject study including 24 healthy participants, was conducted to assess the acute effects of three LSD doses (5, 10, and 20 mcg) on measures of cognition, mood, and subjective experience, up until 6 h after administration. Cognition and subjective experience were assessed using the Psychomotor Vigilance Task, Digit Symbol Substitution Test, Cognitive Control Task, Profile of Mood States, and 5-Dimensional Altered States of Consciousness rating scale. LSD showed positive effects in the majority of observations by increasing positive mood (20 mcg), friendliness (5, 20 mcg), arousal (5 mcg), and decreasing attentional lapses (5, 20 mcg). Negative effects manifested as an increase in confusion (20 mcg) and anxiety (5, 20 mcg). Psychedelic-induced changes in waking consciousness were also present (10, 20 mcg). Overall, the present study demonstrated selective, beneficial effects of low doses of LSD on mood and cognition in the majority of observations. The minimal LSD dose at which subjective and performance effects are notable is 5 mcg and the most apparent effects were visible after 20 mcg.

Hutten, N., Mason, N. L., Dolder, P. C., Theunissen, E. L., Holze, F., Liechti, M. E., Feilding, A., Ramaekers, J. G., & Kuypers, K. (2020). Mood and cognition after administration of low LSD doses in healthy volunteers: A placebo controlled dose-effect finding study. European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 41, 81–91. https://doi.org/10.1016/j.euroneuro.2020.10.002

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Psilocybin exerts distinct effects on resting state networks associated with serotonin and dopamine in mice

November 26, 2021 / Mushrooms / Psilocybin, Neuroscience, Papers / Leave a Comment / By / , , , , , , ,

Abstract

Hallucinogenic agents have been proposed as potent antidepressants; this includes the serotonin (5-HT) receptor 2A agonist psilocybin. In human subjects, psilocybin alters functional connectivity (FC) within the default-mode network (DMN), a constellation of inter-connected regions that displays altered FC in depressive disorders. In this study, we investigated the effects of psilocybin on FC across the entire brain with a view to investigate underlying mechanisms. Psilocybin effects were investigated in lightly-anaesthetized mice using resting-state fMRI. Dual-regression analysis identified reduced FC within the ventral striatum in psilocybin- relative to vehicle-treated mice. Refinement of the analysis using spatial references derived from both gene expression maps and viral tracer projection fields revealed two distinct effects of psilocybin: it increased FC between 5-HT-associated networks and cortical areas, including elements of the murine DMN, thalamus, and midbrain; it decreased FC within dopamine (DA)-associated striatal networks. These results suggest that interactions between 5-HT- and DA-regulated neural networks contribute to the neural and therefore psychological effects of psilocybin. Furthermore, they highlight how information on molecular expression patterns and structural connectivity can assist in the interpretation of pharmaco-fMRI findings.

Grandjean, J., Buehlmann, D., Buerge, M., Sigrist, H., Seifritz, E., Vollenweider, F. X., Pryce, C. R., & Rudin, M. (2021). Psilocybin exerts distinct effects on resting state networks associated with serotonin and dopamine in mice. NeuroImage, 225, 117456. https://doi.org/10.1016/j.neuroimage.2020.117456

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Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects

November 26, 2021 / LSD, Papers / Leave a Comment / By / , , , , , , , , , ,

Abstract

Growing interest has been seen in using lysergic acid diethylamide (LSD) in psychiatric research and therapy. However, no modern studies have evaluated subjective and autonomic effects of different and pharmaceutically well-defined doses of LSD. We used a double-blind, randomized, placebo-controlled, crossover design in 16 healthy subjects (eight women, eight men) who underwent six 25 h sessions and received placebo, LSD (25, 50, 100, and 200 µg), and 200 µg LSD 1 h after administration of the serotonin 5-hydroxytryptamine-2A (5-HT2A) receptor antagonist ketanserin (40 mg). Test days were separated by at least 10 days. Outcome measures included self-rating scales that evaluated subjective effects, autonomic effects, adverse effects, plasma brain-derived neurotrophic factor levels, and pharmacokinetics up to 24 h. The pharmacokinetic-subjective response relationship was evaluated. LSD showed dose-proportional pharmacokinetics and first-order elimination and dose-dependently induced subjective responses starting at the 25 µg dose. A ceiling effect was observed for good drug effects at 100 µg. The 200 µg dose of LSD induced greater ego dissolution than the 100 µg dose and induced significant anxiety. The average duration of subjective effects increased from 6.7 to 11 h with increasing doses of 25-200 µg. LSD moderately increased blood pressure and heart rate. Ketanserin effectively prevented the response to 200 µg LSD. The LSD dose-response curve showed a ceiling effect for subjective good effects, and ego dissolution and anxiety increased further at a dose above 100 µg. These results may assist with dose finding for future LSD research. The full psychedelic effects of LSD are primarily mediated by serotonin 5-HT2A receptor activation.

Holze, F., Vizeli, P., Ley, L., Müller, F., Dolder, P., Stocker, M., Duthaler, U., Varghese, N., Eckert, A., Borgwardt, S., & Liechti, M. E. (2021). Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 46(3), 537–544. https://doi.org/10.1038/s41386-020-00883-6

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Psilocybin exerts distinct effects on resting state networks associated with serotonin and dopamine in mice

February 21, 2022 / Mushrooms / Psilocybin, Neuroscience, Papers / Leave a Comment / By / , , , , , , ,

Abstract

Hallucinogenic agents have been proposed as potent antidepressants; this includes the serotonin (5-HT) receptor 2A agonist psilocybin. In human subjects, psilocybin alters functional connectivity (FC) within the default-mode network (DMN), a constellation of inter-connected regions that displays altered FC in depressive disorders. In this study, we investigated the effects of psilocybin on FC across the entire brain with a view to investigate underlying mechanisms. Psilocybin effects were investigated in lightly-anaesthetized mice using resting-state fMRI. Dual-regression analysis identified reduced FC within the ventral striatum in psilocybin- relative to vehicle-treated mice. Refinement of the analysis using spatial references derived from both gene expression maps and viral tracer projection fields revealed two distinct effects of psilocybin: it increased FC between 5-HT-associated networks and cortical areas, including elements of the murine DMN, thalamus, and midbrain; it decreased FC within dopamine (DA)-associated striatal networks. These results suggest that interactions between 5-HT- and DA-regulated neural networks contribute to the neural and therefore psychological effects of psilocybin. Furthermore, they highlight how information on molecular expression patterns and structural connectivity can assist in the interpretation of pharmaco-fMRI findings.

Grandjean, J., Buehlmann, D., Buerge, M., Sigrist, H., Seifritz, E., Vollenweider, F. X., Pryce, C. R., & Rudin, M. (2021). Psilocybin exerts distinct effects on resting state networks associated with serotonin and dopamine in mice. NeuroImage, 225, 117456. https://doi.org/10.1016/j.neuroimage.2020.117456

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Psychedelic Psychiatry: Preparing for Novel Treatments Involving Altered States of Consciousness

November 26, 2021 / Papers, Psychology / Leave a Comment / By /

Abstract

The past decade has seen a renaissance of research interest into the psychotherapeutic potential of psychedelic compounds. In 2019, Oakland and Denver became the first two jurisdictions in the United States to decriminalize the possession of psychedelic-containing organisms. As research and public policy continue to evolve, it becomes increasingly plausible that psychedelics will become viable treatment options for psychiatric conditions. Psychiatrists should be integral to models of psychedelic prescription and patient management. The risk for adverse psychological and medical effects from psychedelic sessions necessitates psychiatric supervision. The literature on psychedelic-assisted psychotherapy may provide wisdom regarding practical aspects of managing patients’ treatment sessions.

Holoyda B. (2020). Psychedelic Psychiatry: Preparing for Novel Treatments Involving Altered States of Consciousness. Psychiatric services (Washington, D.C.), 71(12), 1297–1299. https://doi.org/10.1176/appi.ps.202000213

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