Depression, Mindfulness, and Psilocybin: Possible Complementary Effects of Mindfulness Meditation and Psilocybin in the Treatment of Depression. A Review

Chronic pain as an emergent property of a complex system and the potential roles of psychedelic therapies

Despite research advances and urgent calls by national and global health organizations, clinical outcomes for millions of people suffering with chronic pain remain poor. We suggest bringing the lens of complexity science to this problem, conceptualizing chronic pain as an emergent property of a complex biopsychosocial system. We frame pain-related physiology, neuroscience, developmental psychology, learning, and epigenetics as components and mini-systems that interact together and with changing socioenvironmental conditions, as an overarching complex system that gives rise to the emergent phenomenon of chronic pain. We postulate that the behavior of complex systems may help to explain persistence of chronic pain despite current treatments. From this perspective, chronic pain may benefit from therapies that can be both disruptive and adaptive at higher orders within the complex system. We explore psychedelic-assisted therapies and how these may overlap with and complement mindfulness-based approaches to this end. Both mindfulness and psychedelic therapies have been shown to have transdiagnostic value, due in part to disruptive effects on rigid cognitive, emotional, and behavioral patterns as well their ability to promote neuroplasticity. Psychedelic therapies may hold unique promise for the management of chronic pain.

Psilocybin enhances insightfulness in meditation: a perspective on the global topology of brain imaging during meditation

In this study, for the first time, we explored a dataset of functional magnetic resonance images collected during focused attention and open monitoring meditation before and after a five-day psilocybin-assisted meditation retreat using a recently established approach, based on the Mapper algorithm from topological data analysis. After generating subject-specific maps for two groups (psilocybin vs. placebo, 18 subjects/group) of experienced meditators, organizational principles were uncovered using graph topological tools, including the optimal transport (OT) distance, a geometrically rich measure of similarity between brain activity patterns. This revealed characteristics of the topology (i.e. shape) in space (i.e. abstract space of voxels) and time dimension of whole-brain activity patterns during different styles of meditation and psilocybin-induced alterations. Most interestingly, we found that (psilocybin-induced) positive derealization, which fosters insightfulness specifically when accompanied by enhanced open-monitoring meditation, was linked to the OT distance between open-monitoring and resting state. Our findings suggest that enhanced meta-awareness through meditation practice in experienced meditators combined with potential psilocybin-induced positive alterations in perception mediate insightfulness. Together, these findings provide a novel perspective on meditation and psychedelics that may reveal potential novel brain markers for positive synergistic effects between mindfulness practices and psilocybin.

The effect of psilocybin on empathy and prosocial behavior: a proposed mechanism for enduring antidepressant effects

Psilocybin is a serotonergic psychedelic shown to have enduring antidepressant effects. Currently, the mechanism for its enduring effects is not well understood. Empathy and prosocial behavior may be important for understanding the therapeutic benefit of psilocybin. In this article we review the effect of psilocybin on empathy and prosocial behavior. Moreover, we propose that psilocybin may induce a positive feedback loop involving empathy and prosocial behavior which helps explain the observed, enduring antidepressant effects.

Unveiling the Psychedelic Journey: An Appraisal of Psilocybin as a Profound Antidepressant Therapy

Depression, a global health concern with significant implications for suicide rates, remains challenging to treat effectively with conventional pharmacological options. The existing pharmaceutical interventions for these illnesses need daily dosing, are accompanied by various adverse effects, and may exhibit limited efficacy in certain cases. However, hope emerges from an unlikely source-Psilocybin, a natural hallucinogen found in certain mushrooms. Recently, this enigmatic compound has garnered attention for its potential therapeutic benefits in addressing various mental health issues, including depression. Psilocybin alters mood, cognition, and perception by acting on a particular subtype of serotonin receptors in the brain. It's feasible that these shifts in consciousness will promote healing development, offering a novel approach to depression management. This comprehensive review explores psilocybin, derived from specific mushrooms, and its implications in the treatment of depression. The study examines new perspectives and therapeutic possibilities surrounding psilocybin, addressing existing gaps in academic literature. It delves into its biosynthesis, unique mechanisms of action, therapeutic applications, and anti-depressive effects. By uncovering the potential of this mind-altering substance, the review aims to advance psychiatric care, offering hope to those globally affected by depression.

Mindfulness meditation and psychedelics: potential synergies and commonalities

There has been increasing scientific and clinical interest in studying psychedelic and meditation-based interventions in recent years, both in the context of improving mental health and as tools for understanding the mind. Several authors suggest neurophysiological and phenomenological parallels and overlaps between psychedelic and meditative states and suggest synergistic effects of both methods. Both psychedelic-assisted therapy and meditation training in the form of mindfulness-based interventions have been experimentally validated with moderate to large effects as alternative treatments for a variety of mental health problems, including depression, addictions, and anxiety disorders. Both demonstrated significant post-acute and long-term decreases in clinical symptoms and enhancements in well-being in healthy participants, in addition. Postulated shared salutogenic mechanisms, include, among others the ability to alter self-consciousness, present-moment awareness and antidepressant action via corresponding neuromodulatory effects. These shared mechanisms between mindfulness training and psychedelic intervention have led to scientists theorizing, and recently demonstrating, positive synergistic effects when both are used in combination. Research findings suggest that these two approaches can complement each other, enhancing the positive effects of both interventions. However, more theoretical accounts and methodologically sound research are needed before they can be extended into clinical practice. The current review aims to discuss the theoretical rationale of combining psychedelics with mindfulness training, including the predictive coding framework as well as research findings regarding synergies and commonalities between mindfulness training and psychedelic intervention. In addition, suggestions how to combine the two modalities are provided.

Altered states of leadership: mindfulness meditation, psychedelic use, and leadership development

Background

Previous research suggests that mindfulness meditation and psychedelic substances show promise as mental health interventions, but relatively little remains known about their potential impact on leadership outcomes.

Aims

This study aimed to investigate if and how mindfulness meditation and psychedelic use may impact leadership among respondents with a management position as their primary role at work.

Methods

Using samples representative of the US and UK adult populations with regard to sex, age, and ethnicity, this study used quantitative and qualitative methods to examine if and how mindfulness meditation and psychedelic use may impact leadership.

Results

Among respondents with a management position as their primary role at work (n = 3,150), 1,373 reported having tried mindfulness meditation and 559 reported having tried psychedelics. In covariate-adjusted regression analyses, both lifetime number of hours of mindfulness meditation practice and greater psychological insight during respondents' most intense psychedelic experience were associated with describing a positive impact on leadership (ORs = 2.33, 3.49; ps < 0.001), while qualitative analyses revealed nuances in the type of impacts mindfulness meditation and psychedelic use had on leadership. There were several subthemes (e.g., focus, creativity, patience, empathy, compassion) that were frequently reported with both mindfulness meditation and psychedelic use. There were also unique subthemes that were more commonly reported with mindfulness meditation (e.g., improved sleep, stress reduction, calming effects) and psychedelic use (e.g., greater self-understanding, less hierarchical attitudes toward colleagues, positive changes in interpersonal attitudes and behaviors), respectively.

Conclusion

Although causality cannot be inferred due to the research design, the findings in this study suggest potential complementary effects of mindfulness meditation and psychedelic use on leadership, which could inspire new approaches in leadership development.

Psychedelic unselfing: self-transcendence and change of values in psychedelic experiences

Psychedelic experiences have been shown to both facilitate (re)connection to one's values and change values, including enhancing aesthetic appreciation, promoting pro-environmental attitudes, and encouraging prosocial behavior. This article presents an empirically informed framework of philosophical psychology to understand how self-transcendence relates to psychedelic value changes. Most of the observed psychedelic value changes are toward the self-transcendent values of Schwartz's value theory. As psychedelics also reliably cause various self-transcendent experiences (STEs), a parsimonious hypothesis is that STEs change values toward self-transcendent values. I argue that STEs indeed can lead to value changes, and discuss the morally relevant process of self-transcendence through Iris Murdoch's concept of "unselfing". I argue that overt egocentric concerns easily bias one's valuations. Unselfing reduces egocentric attributions of salience and enhances non-egocentric attention to the world, widening one's perspective and shifting evaluation toward self-transcendent modes. Values are inherently tied to various evaluative contexts, and unselfing can attune the individual to evaluative contexts and accompanying values beyond the self. Understood this way, psychedelics can provide temporarily enhanced access to self-transcendent values and function as sources of aspiration and value change. However, contextual factors can complicate whether STEs lead to long-term changes in values. The framework is supported by various research strands establishing empirical and conceptual connections between long-term differences in egocentricity, STEs, and self-transcendent values. Furthermore, the link between unselfing and value changes is supported by phenomenological and theoretical analysis of psychedelic experiences, as well as empirical findings on their long-term effects. This article furthers understanding of psychedelic value changes and contributes to discussions on whether value changes are justified, whether they result from cultural context, and whether psychedelics could function as tools of moral neuroenhancement.

Classic psychedelic use and current meditation practice

Objectives

Previous research has investigated potential synergies between classic psychedelics and meditation practice, but relatively little remains known about the relationship between classic psychedelic experiences and engagement with meditation practice.The purpose of this study was to investigate associations between classic psychedelic experiences and engagement with two popular types of meditation: mindfulness meditation and loving-kindness or compassion meditation.

Methods

This retrospective, population-based observational study included 2,822 respondents aged 18 years or older in the United States. Using covariate-adjusted regression models, this study examined associations of classic psychedelic experiences with current practice of mindfulness meditation and loving-kindness or compassion meditation.

Results

In covariate-adjusted regression models, lifetime classic psychedelic use was associated with a higher frequency of current mindfulness meditation practice but not current loving-kindness or compassion meditation practice. Both psychological insight and "ego dissolution" were associated with a higher frequency of current mindfulness meditation practice and current loving-kindness or compassion meditation practice. Notably, when psychological insight and "ego dissolution" were entered into the regression model simultaneously, only greater psychological insight was associated with having a higher frequency of current mindfulness meditation practice and current loving-kindness or compassion meditation practice.

Conclusion

Although the findings in this study cannot demonstrate causality, they suggest that classic psychedelic experiences may exert a positive effect on the cultivation and maintenance of health-related behaviors such as regular meditation practice, with psychological insight appearing to be a stronger predictor than "ego dissolution."

Preregistration

This study was not preregistered.

The Use of Psilocybin in the Treatment of Psychiatric Disorders with Attention to Relative Safety Profile: A Systematic Review

There has been a reemergence of research into the use of substances such as LSD, MDMA, and psilocybin for the treatment of psychiatric disorders. This increase in consideration toward the medicinal use of these compounds has been termed the "Psychedelic Renaissance." This article specifically explores the background of psilocybin, a psychoactive compound that is naturally derived from certain species of fungi. Pubmed was searched by one doctoral-level researcher using specific Boolean operator terms. The results were filtered by title and abstract and 76 articles were screened and analyzed in full detail. Oral psilocybin is showing itself to be clinically efficacious by producing statistically significant reductions in depression and anxiety symptoms over time versus control in multiple clinical trials. It has also been shown to reduce cigarettes per day and drinks per day in patients with substance use disorders. Thus far, there have been no significant adverse clinical events from psilocybin and there also have been no verifiable recorded deaths reported. Larger studies need to be performed before the drug can potentially become approved for use in the general population.

Lasting increases in trait mindfulness after psilocybin correlate positively with the mystical-type experience in healthy individuals

Background

Psilocybin-induced mystical-type experiences are associated with lasting positive psychological outcomes. Recent studies indicate that trait mindfulness is increased 3 months after psilocybin intake, preceded by decreases in neocortical serotonin 2A receptor (5-HT_2AR) binding. However, the association between psilocybin-induced mystical-type experiences and subsequent changes in trait mindfulness remains unexplored, as does the association between pre-drug trait mindfulness and 5-HT_2AR binding in the healthy brain.

Aim

We evaluated whether psilocybin induced lasting increases in trait mindfulness in healthy volunteers, and whether the mystical-type experience was associated with this increase. We further examined the association between pre-drug trait mindfulness and 5-HT_2AR binding in neocortex and selected frontolimbic regions.

Materials and methods

Forty-six medium-high dose psilocybin sessions were conducted in 39 healthy individuals. The mystical-type experience was measured with the Mystical Experience Questionnaire (MEQ) at the end of the session. Trait mindfulness was measured using the Mindful Attention and Awareness Scale (MAAS) at baseline and 3 months after the psilocybin session. Thirty-two of the participants completed pre-drug [¹¹C]-Cimbi-36 positron emission tomography (PET) to assess 5-HT_2AR binding in neocortex and, post-hoc, in the frontolimbic regions amygdala, frontal cortex, and anterior cingulate cortex.

Results

The MAAS score was significantly increased at 3-month follow-up (p = 3.24 × 10^–6), a change positively associated with the MEQ score (p = 0.035). Although the association between pre-drug MAAS score and neocortex 5-HT_2AR binding was not significant (p = 0.24), post-hoc analyses revealed a significant negative association between MAAS and right amygdala 5-HT_2AR binding (p_FWER = 0.008).

Conclusion

We here show that lasting changes in trait mindfulness following psilocybin administration are positively associated with intensity of the mystical-type experience, suggesting that the acute phenomenology of psilocybin facilitates a shift in awareness conducive for mindful living. We furthermore show that higher pre-drug trait mindfulness is associated with reduced 5-HT_2AR binding in the right amygdala.

Neural Mechanisms and Psychology of Psychedelic Ego Dissolution

Neuroimaging studies of psychedelics have advanced our understanding of hierarchical brain organization and the mechanisms underlying their subjective and therapeutic effects. The primary mechanism of action of classic psychedelics is binding to serotonergic 5-HT2A receptors. Agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy that can have a profound effect on hierarchical message-passing in the brain. Here, we review the cognitive and neuroimaging evidence for the effects of psychedelics: in particular, their influence on selfhood and subject-object boundaries-known as ego dissolution-surmised to underwrite their subjective and therapeutic effects. Agonism of 5-HT2A receptors, located at the apex of the cortical hierarchy, may have a particularly powerful effect on sentience and consciousness. These effects can endure well after the pharmacological half-life, suggesting that psychedelics may have effects on neural plasticity that may play a role in their therapeutic efficacy. Psychologically, this may be accompanied by a disarming of ego resistance that increases the repertoire of perceptual hypotheses and affords alternate pathways for thought and behavior, including those that undergird selfhood. We consider the interaction between serotonergic neuromodulation and sentience through the lens of hierarchical predictive coding, which speaks to the value of psychedelics in understanding how we make sense of the world and specific predictions about effective connectivity in cortical hierarchies that can be tested using functional neuroimaging. SIGNIFICANCE STATEMENT: Classic psychedelics bind to serotonergic 5-HT2A receptors. Their agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy, resulting in a profound effect on information processing in the brain. Here, we synthesize an abundance of brain imaging research with pharmacological and psychological interpretations informed by the framework of predictive coding. Moreover, predictive coding is suggested to offer more sophisticated interpretations of neuroimaging findings by bridging the role between the 5-HT2A receptors and large-scale brain networks.

Potential Therapeutic Effects of Psilocybin: A Systematic Review

Psilocybin is a plant alkaloid that is derived from precursors of tryptamine and is present in many different types of mushrooms. It has been utilized by indigenous peoples of Central and South America for centuries in a ceremonial setting to promote spiritual experiences. Indigenous societies have long employed psilocybin and other 5-HT 2A agonist classic psychedelics in their rites. They were a focus in psychiatry in the middle of the 20th century as both experimental medicines and tools for studying brain function. Due to the fact that traditional psychedelics were being used for purposes other than medical research and in connection with the burgeoning counterculture by the late 1960s and early 1970s, these scientific investigations fell out of favor. However, thanks to a number of encouraging studies that validated the earlier research, interest in traditional psychedelics has surged among scientists in the 21st century. In this review, we examine therapeutic studies on psilocybin, the traditional psychedelic that has received the lion's share of recent attention. According to three controlled studies, psilocybin may reduce symptoms of depression and anxiety in the context of cancer-related psychological discomfort for at least six months after a single acute treatment for mood and anxiety disorders. Three months after two acute doses, individuals in a small, open-label study with treatment-resistant depression reported fewer depressive and anxiety symptoms. Small, open-label pilot studies on addiction have demonstrated encouraging success rates for alcohol and cigarette addiction. The review also briefly discusses the synthesis, mechanism of action, effects, molecular pharmacology, adverse effects, and contraindications of psilocybin.

Combinatorial approaches for treating neuropsychiatric social impairment

Social behaviour is an essential component of human life and deficits in social function are seen across multiple psychiatric conditions with high morbidity. However, there are currently no FDA-approved treatments for social dysfunction. Since social cognition and behaviour rely on multiple signalling processes acting in concert across various neural networks, treatments aimed at social function may inherently require a combinatorial approach. Here, we describe the social neurobiology of the oxytocin and endocannabinoid signalling systems as well as translational evidence for their use in treating symptoms in the social domain. We leverage this systems neurobiology to propose a network-based framework that involves pharmacology, psychotherapy, non-invasive brain stimulation and social skills training to combinatorially target trans-diagnostic social impairment. Lastly, we discuss the combined use of oxytocin and endocannabinoids within our proposed framework as an illustrative strategy to treat specific aspects of social function. Using this framework provides a roadmap for actionable treatment strategies for neuropsychiatric social impairment. This article is part of the theme issue 'Interplays between oxytocin and other neuromodulators in shaping complex social behaviours'.

Psychedelics in the treatment of unipolar and bipolar depression

This is a narrative review about the role of classic and two atypical psychedelics in the treatment of unipolar and bipolar depression. Since the 1990s, psychedelics experience a renaissance in biomedical research. The so-called classic psychedelics include lysergic acid diethylamide (LSD), psilocybin, mescaline and ayahuasca. Characteristic effects like alterations in sensory perception, as well as emotion- and self-processing are induced by stimulation of serotonin 2A receptors in cortical areas. The new paradigm of psychedelic-assisted psychotherapy suggests a therapeutic framework in which a safely conducted psychedelic experience is integrated into a continuous psychotherapeutic process. First randomized, controlled trials with psilocybin show promising efficacy, tolerability, and adherence in the treatment of unipolar depression. On the other hand, classic psychedelics seem to be associated with the induction of mania, which is an important issue to consider for the design of research and clinical protocols. So called atypical psychedelics are a heterogeneous group with overlapping subjective effects but different neurobiological mechanisms. Two examples of therapeutic value in psychiatry are 3,4-methyl​enedioxy​methamphetamine (MDMA) and ketamine. Since 2020 the ketamine enantiomer esketamine has been granted international approval for treatment-resistant unipolar depression, and also first evidence exists for the therapeutic efficacy of ketamine in bipolar depression. Whether psychedelics will fulfil current expectations and find their way into broader clinical use will depend on future rigorous clinical trials with larger sample sizes. A well-considered therapeutic and legal framework will be crucial for these substances to create new treatment settings and a potential paradigm shift.

Mystical Experience

This paper proposes to study mystical experience by contrasting it with “ordinary” experience, i.e., with standard consciousness. It emphasises the construed nature of standard consciousness and the role that the mutual connectedness of mental contents plays in its construction. It then shows that removal of the factors that are responsible for the “making” of standard consciousness accounts for the principal features of mystical experience; these features are, therefore, mainly negative. Understanding mystical experience as the suppression of factors that contribute to the construction of standard consciousness, along with a discussion of the mechanism that makes this possible, permits answers to some frequently asked questions, such as: Why is mystical experience ineffable? What is its epistemic status? Does it have implications for our understanding of mind, consciousness, and self?

Psychedelic Microdosing, Mindfulness, and Anxiety: A Cross-Sectional Mediation Study

While anecdotal reports claim that psychedelic microdosing reduces anxiety and mood symptoms, evidence supporting these claims is scarce. This cross-sectional study investigated the association between microdosing and trait anxiety. Furthermore, it was investigated if trait mindfulness mediated this association. Participants completed anonymous online questionnaires and were divided into three groups: current microdosers (n = 186), former microdosers (n = 77) and microdosing-naïve controls (n = 234). Trait anxiety and trait mindfulness were measured using the State-Trait Anxiety Inventory - Trait subscale (STAI-T) and the 15-item Five-Facet Mindfulness Questionnaire (FFMQ-15) respectively. Current and former microdosers reported lower STAI-T scores compared to microdosing-naïve controls. Furthermore, associations of current and former microdosing with trait anxiety were mediated by trait mindfulness, with small effects of FFMQ-15 Total, Non-judging and Non-reactivity scores. However, in an exploratory analysis, all associations between microdosing and STAI-T scores became non-significant when participants with previous macrodose experience (n = 386) were excluded. Our findings suggest that RCT<apos;>s are warranted to test causal hypotheses concerning the effects of microdosing and the role of trait mindfulness in the effects of microdosing, while controlling for previous macrodose experience.

The Psychedelic Integration Scales: Tools for Measuring Psychedelic Integration Behaviors and Experiences

In this study, we describe the development and initial validation of two psychometric scales for measuring psychedelic integration. Psychedelic integration refers to the post-acute period of time following psychedelic drug administration. We created the Integration Engagement Scale (IES) to capture positive behavioral engagement with integration and the Experienced Integration Scale (EIS) to capture internal aspects of feeling integrated. These scales were developed to measure post-acute psychedelic administration dynamics in order to inform the creation of enhanced integration support and to help refine a general conceptual understanding of the construct of psychedelic integration. The scales are brief and face valid instruments designed for practical use in applied and research settings. Scale items were generated and refined using the Iterative Process Model of scale development, with input from psychedelics experts and clinicians. Content validity, internal structure, and reliability were assessed via expert surveys, content validity analysis, cognitive interviewing, convergent validity analysis, exploratory factor analysis, and confirmatory factor analysis. The data indicates the scales are valid and reliable measurements of the behavioral and experiential forms of Psychedelic Integration.

Palliative care provider attitudes toward existential distress and treatment with psychedelic-assisted therapies

Background

Existential distress is a significant source of suffering for patients facing life-threatening illness. Psychedelic-Assisted Therapies (PAT) are novel treatments that have shown promise in treating existential distress, but openness to providing PAT may be limited by stigma surrounding psychedelics and the paucity of education regarding their medical use. How PAT might be integrated into existing treatments for existential distress within palliative care remains underexplored.

Methods

The present study aimed to elucidate the attitudes of palliative care clinicians regarding treatments for existential distress, including PAT. We recruited palliative care physicians, advanced practice nurses, and spiritual and psychological care providers from multiple US sites using purposive and snowball sampling methods. Attitudes toward PAT were unknown prior to study involvement. Semi-structured interviews targeted at current approaches to existential distress and attitudes toward PAT were analyzed for thematic content.

Results

Nineteen respondents (seven physicians, four advanced practice nurses, four chaplains, three social workers, and one psychologist) were interviewed. Identified themes were 1) Existential distress is a common experience that is frequently insufficiently treated within the current treatment framework; 2) Palliative care providers ultimately see existential distress as a psychosocial-spiritual problem that evades medicalized approaches; 3) Palliative care providers believe PAT hold promise for treating existential distress but that a stronger evidence base is needed; 4) Because PAT do not currently fit existing models of existential distress treatment, barriers remain.

Conclusions

PAT is seen as a potentially powerful tool to treat refractory existential distress. Larger clinical trials and educational outreach are needed to clarify treatment targets and address safety concerns. Further work to adapt PAT to palliative care settings should emphasize collaboration with spiritual care as well as mental health providers and seek to address unresolved concerns about equitable access.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12904-021-00889-x.

Psilocybin, a Naturally Occurring Indoleamine Compound, Could Be Useful to Prevent Suicidal Behaviors

The available interventions for people who are at risk of suicide have limited efficacy. Recently, research on new mental health treatments has started to consider psychedelic compounds, particularly psilocybin, a molecule with a few thousand years of history of use in human societies. The possible effects of psilocybin on suicidal ideation and behaviors have not been specifically studied yet; however, the current knowledge on the suicidal process and the available data on es/ketamine suggest that psylocibin could be used to modulate the thoughts and behavioral patterns in individuals who are at risk of suicidal behaviors. Here, we summarize the available evidence on the possible mechanisms underlying psilocybin positive effects on suicide risk. Major pathways related to suicidal behaviors that might be modulated by psylocibin include serotonin receptors. Specifically, psylocibin directly stimulates the serotonin 2A receptor (5HT_2A), targeting the inflammatory and oxidative stress pathways and leading to a rapid increase in brain plasticity and inflammation suppression and increases in cognitive flexibility, spirituality, and empathy. We also present preliminary epidemiological data and provide a rationale for studying psilocybin in individuals with suicidal ideation or who are at risk of suicidal behaviors. This review presents a framework to understand the basis for psilocybin use in individuals who are at risk of suicidal behaviors and calls for clinical studies.

Neuroplasticity as a convergent mechanism of ketamine and classical psychedelics

The emerging therapeutic efficacy of ketamine and classical psychedelics for depression has inspired tremendous interest in the underlying neurobiological mechanisms. We review preclinical and clinical evidence supporting neuroplasticity as a convergent downstream mechanism of action for these novel fast-acting antidepressants. Through their primary glutamate or serotonin receptor targets, ketamine and psychedelics [psilocybin, lysergic acid diethylamide (LSD), and N,N-dimethyltryptamine (DMT)] induce synaptic, structural, and functional changes, particularly in pyramidal neurons in the prefrontal cortex. These include increased glutamate release, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) activation, brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR)-mediated signaling, expression of synaptic proteins, and synaptogenesis. Such influences may facilitate adaptive rewiring of pathological neurocircuitry, thus providing a neuroplasticity-focused framework to explain the robust and sustained therapeutic effects of these compounds.

New Insights Into the Clinical and Nonclinical Effects of Psychedelic Substances

Abstract. After decades of stagnation, research on psychedelic substances (such as lysergic acid diethylamide [LSD], psilocybin, or N,N-dimethyltryptamine [DMT]) has experienced a renaissance over the last 10 years, with various major research programs being conducted across Europe and the United States. This research primarily investigates the potential of psychedelics in the treatment of mental health disorders, their short- and long-term effects on recreational users, and the neurological and cognitive processes responsible for their effects. The present review provides a concise summary of the most recent insights gained from this research. We briefly outline the history of psychedelic research, the objective and subjective effects caused by these substances, the prevalence and socio-psychological correlates of their use, as well as their potential for harm. Subsequently, we review empirical research on the beneficial effects of psychedelics in clinical samples, focusing on their efficacy in the treatment of major depression, anxiety, and substance use disorders, and discuss research on the proposed neural and cognitive mechanisms behind these effects. We then review research on their effects on healthy subjects, focusing on psychological well-being as well as changes in personality, nature-relatedness, and creativity. Finally, we review empirical evidence regarding the long-term effects of single experiences with psychedelics and conclude with a summary and outlook.

From psychiatry to neurology: Psychedelics as prospective therapeutics for neurodegenerative disorders

The studies of psychedelics, especially psychedelic tryptamines like psilocybin, are rapidly gaining interest in neuroscience research. Much of this interest stems from recent clinical studies demonstrating that they have a unique ability to improve the debilitating symptoms of major depressive disorder (MDD) long-term after only a single treatment. Indeed, the Food and Drug Administration (FDA) has recently designated two Phase III clinical trials studying the ability of psilocybin to treat forms of MDD with "Breakthrough Therapy" status. If successful, the use of psychedelics to treat psychiatric diseases like depression would be revolutionary. As more evidence appears in the scientific literature to support their use in psychiatry to treat MDD on and substance use disorders (SUD), recent studies with rodents revealed that their therapeutic effects might extend beyond treating MDD and SUD. For example, psychedelics may have efficacy in the treatment and prevention of brain injury and neurodegenerative diseases such as Alzheimer's Disease. Preclinical work has highlighted psychedelics' ability to induce neuroplasticity and synaptogenesis, and neural progenitor cell proliferation. Psychedelics may also act as immunomodulators by reducing levels of proinflammatory biomarkers, including IL-1β, IL-6, and tumor necrosis factor-α (TNF-α). Their exact molecular mechanisms, and induction of cellular interactions, especially between neural and glial cells, leading to therapeutic efficacy, remain to be determined. In this review, we discuss recent findings and information on how psychedelics may act therapeutically on cells within the central nervous system (CNS) during brain injuries and neurodegenerative diseases.

Combining Psychedelic and Mindfulness Interventions: Synergies to Inform Clinical Practice

Psychedelic and mindfulness interventions have been shown to improve mental ill-health and wellbeing, with a range of clinical processes and effects in common. However, each appear to contain specific challenges in the context of mental health treatment. In this Perspective, we focus on a set of distinct affordances, "useful differences", within psychedelic and mindfulness interventions that might address common challenges within the other intervention. Accordingly, we propose a set of applied synergies, indicating specific ways in which these two promising interventions might be combined for greater benefit. Metaphorically, on the journey toward mental health and wellbeing, we propose that psychedelic treatments may serve the role of Compass (initiating, motivating, and steering the course of mindfulness practice), with mindfulness interventions serving the role of Vehicle (integrating, deepening, generalizing, and maintaining the novel perspectives and motivation instigated by psychedelic experience). We outline a set of testable hypotheses and future research associated with the synergistic action of psychedelic and mindfulness interventions toward improved clinical outcomes.

A Spectrum of Selves Reinforced in Multilevel Coherence: A Contextual Behavioural Response to the Challenges of Psychedelic-Assisted Therapy Development

Psychedelic-assisted therapy research for depression and PTSD has been fast tracked in the United States with the Food and Drugs Administration (FDA) granting breakthrough designations for MDMA (post-traumatic stress disorder) and psilocybin (major depressive disorder). The psychotherapeutic treatments accompanying these psychedelics have not been well-studied and remain controversial. This article reviews the challenges unique to psychedelic-assisted therapy and introduces a newly optimised psychological flexibility model that adapts Contextual Behavioural Science (CBS)/Acceptance and Commitment Therapy (ACT) to those multiple challenges, including ego inflation, traumatic memories, and the perceived presence of entities. A methodology aligned with biological mechanisms, psychological processes and therapeutic contexts may be advantageous for improving outcomes. This model expands ACT by integrating practices and data from psychedelic-assisted therapy research into a Contextual Behavioural Science framework, allowing both fields to inform each other. Psychological flexibility processes are questioned and adapted to a psychedelic context, and interventions that operationalise these processes are considered. The principle through-line of the paper is to consider varied constructs of Self, as understood by these fields, and integrates respective elements of varied self-models, interventions and data into a Spectrum of Selves model for psychedelic-assisted therapy. Secondly the paper examines how to select and retain new self-perspectives and their corresponding behaviours systemically, drawing from evolutionary science principles. A case example of such behavioural reinforcement is provided, as well as a psychedelic integration checklist to guide the practical implementation of such an approach. This method can enable a coherent therapeutic framework with clear operational relationships between (1) problematic behaviour patterns that an individual wishes to address (2) the guided psychedelic experiences of that individual, and (3) the barriers to maintaining any changes, thus increasing theoretical-practical coherence, broadening treatment benefits and reducing relapse in psychedelic-assisted therapy. Research questions for further developing a CBS-consistent psychedelic-assisted therapy are offered.

A continuum hypothesis of psychotomimetic rapid antidepressants

Ketamine, classical psychedelics and sleep deprivation are associated with rapid effects on depression. Interestingly, these interventions also have common psychotomimetic actions, mirroring aspects of psychosis such as an altered sense of self, perceptual distortions and distorted thinking. This raises the question whether these interventions might be acute antidepressants through the same mechanisms that underlie some of their psychotomimetic effects. That is, perhaps some symptoms of depression can be understood as occupying the opposite end of a spectrum where elements of psychosis can be found on the other side. This review aims at reviewing the evidence underlying a proposed continuum hypothesis of psychotomimetic rapid antidepressants, suggesting that a range of psychotomimetic interventions are also acute antidepressants as well as trying to explain these common features in a hierarchical predictive coding framework, where we hypothesise that these interventions share a common mechanism by increasing the flexibility of prior expectations. Neurobiological mechanisms at play and the role of different neuromodulatory systems affected by these interventions and their role in controlling the precision of prior expectations and new sensory evidence will be reviewed. The proposed hypothesis will also be discussed in relation to other existing theories of antidepressants. We also suggest a number of novel experiments to test the hypothesis and highlight research areas that could provide further insights, in the hope to better understand the acute antidepressant properties of these interventions.

Examining the Potential Synergistic Effects Between Mindfulness Training and Psychedelic-Assisted Therapy

Mindfulness-based interventions and psychedelic-assisted therapy have been experimentally utilised in recent years as alternative treatments for various psychopathologies with moderate to great success. Both have also demonstrated significant post-acute and long-term decreases in clinical symptoms and enhancements in well-being in healthy participants. These two therapeutic interventions share various postulated salutogenic mechanisms, such as the ability to alter present-moment awareness and anti-depressive action, via corresponding neuromodulatory effects. Recent preliminary evidence has also demonstrated that psychedelic administration can enhance mindfulness capacities which has already been demonstrated robustly as a result of mindfulness-based interventions. These shared mechanisms between mindfulness-based interventions and psychedelic therapy have led to scientists theorising, and recently demonstrating, synergistic effects when both are used in combination, in the form of potentiated therapeutic benefit. These synergistic results hold great promise but require replication in bigger sample groups and better controlled methodologies, to fully delineate the effect of set and setting, before they can be extended onto clinical populations.

Virtual Reality and Psychedelics for the Treatment of Psychiatric Disease: A Systematic Literature Review

OBJECTIVE

Hallucinogenic substances or psychedelic drugs have been historically used by humans worldwide for centuries, and interest grows around them because of the therapeutic potential that they pose for mental disease. Virtual Reality (VR), has been highly developed and improved in the last decade, and it is also gaining importance due to their potential as therapeutic tools. In this article, the most recent and relevant information regarding the medical applications of both VR and psychedelics was highlighted, and diverse potential therapeutic uses were explored in hope to set the ground for further research on this topic.

METHOD

A systematic literature review using the PRISMA methods was conducted in PubMed, Medline, Embase, Cochrane Library, Scopus and Web of Science, including only peer-reviewed clinical trials or case studies written in English, that address the use of psychedelics and/or VR for the treatment of psychiatric disorders and that measure the success of the therapies. A final selection of 23 manuscripts were used in this systematic review.

RESULTS

VR showed security and significant efficacy in the management of special cases of phobias (social, motion pain and spiders), eating disorder, post-traumatic stress disorder (PTSD), gambling disorder, preoperative anxiety and schizophrenia.

CONCLUSIONS

The hallucinogenic drugs evaluated exhibited positive effects in treatment of depressive and anxiety disorders, alcohol dependence and PTSD. More research is needed in order to test the effectiveness of these therapies (alone or together) in different mental illnesses and different populations.

Scutellarin protects against lipopolysaccharide-induced behavioral deficits by inhibiting neuroinflammation and microglia activation in rats

Depression is a complex and heterogeneous mental disorder. Yet, the mechanisms behind depression remain elusive. Increasing evidence suggests that inflammatory reaction and microglia activation are involved in the pathogenesis of depression. Scutellarin has been found to have anti-inflammatory and antioxidant effects in various diseases. The aim of the present study was to investigate the anti-depressant effects and potential mechanism of scutellarin in the lipopolysaccharide (LPS)-induced depression animal model. The behavioral tests showed that scutellarin administration ameliorated LPS-induced depressive-like behaviors. Additionally, the scutellarin treatment inhibited reactive oxygen species (ROS) generation. Western blot analysis results showed that scutellarin pretreatment suppressed LPS-induced the protein levels of NLRP3, caspase-1, and IL-1β. Furthermore, immunostaining results showed that scutellarin pretreatment inhibited LPS-induced microglia activation in the hippocampus of rats. These findings suggest that scutellarin effectively improves LPS-induced inflammation-related depressive-like behaviors by inhibiting LPS-induced neuroinflammation and microglia activation, possibly via regulation of the ROS/NLRP3 signaling pathway and microglia activation. Thus, scutellarin may serve as a potential therapeutic strategy for depression.