Safety issues of psilocybin and LSD as potential rapid acting antidepressants and potential challenges

Psilocybin for clinical indications: A scoping review

BACKGROUND

Psychedelic drugs have been of interest in medicine since the early 1950s. There has recently been a resurgence of interest in psychedelics.

AIMS

The objective of this study is to determine the extent of the available literature on psilocybin for medical indications including the designs used, study characteristics, indications studied, doses, and authors' conclusions. We identify areas for further study where there are research gaps.

METHODS

We conducted a systematic scoping review of clinical indications for psilocybin, encompassing psychiatric and medical conditions. We systematically searched Medline and Embase using keywords related to psilocybin. We reviewed titles and texts in duplicate using Covidence software. We extracted data individually in duplicate using Covidence software and a senior reviewer resolved all author conflicts. We analyzed data descriptively.

RESULTS

We included 193 published and 80 ongoing studies. Thirty-seven percent of included studies were systematic reviews. Only 12% of included studies were randomized controlled trials. The median number of participants was 22 with a median of 18 participants who had taken psilocybin. Thirty-eight percent of studies reported at least one potential conflict of interest. The most common indication was depression (28%). Also commonly studied were substance use (14%), mental health in life-threatening illness (9%), headaches (6%), depression and anxiety (6%), obsessive-compulsive disorder (3%), and anxiety disorders (3%).

CONCLUSIONS

Most studies involving the administration of psilocybin have small sample sizes and the most common focus has been psychiatric disorders. There is a need for high-quality randomized trials on psilocybin and to expand consideration to other promising indications, such as chronic pain.

Psychedelics as a tool for a more connected and sustainable world? Considering the importance of rituals, boundaries, and commitment

Despite the surge of interest in psychedelic research in the past decade, largely due to the promise of psychedelics for improving mental health outcomes, there has been comparatively little discussion about the social and environmental consequences of psychedelic drug use. While there is growing evidence to suggest psychedelics could foster a greater connection to the natural world and improve social relationships, such positive repercussions are far from guaranteed. In this commentary, we focus on LSD, psilocybin and especially MDMA, and outline three insights we came to see as crucial to creating beneficial outcomes: 1) the importance of setting and rituals, 2) the establishment of boundaries, and 3) understanding the long-term commitment required. These insights are grounded in the history of psychedelics, which is intimately intertwined with ritualised use, yet the process of commercialisation of these substances threatens to strip away important contextual factors. Creating boundaries around when, how and with whom psychedelics are used have been found to protect recreational users from harm and could also be instrumental in steering commercial interests to align with socio-environmental goals. Finally, far from being a 'quick fix' for social or environmental problems, the use of psychedelics requires sustained engagement to integrate the insights obtained. Whereas we remain optimistic about the transformative potential of psychedelics for social relationships and the environment, we also emphasise the need for a more cautious, considered approach if we are to harness the benefits and minimise the challenges of psychedelic drug use.

Modulation of functional networks related to the serotonin neurotransmitter system by citalopram: Evidence from a multimodal neuroimaging study

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) potentiate serotonergic neurotransmission by blocking the serotonin transporter (5-HTT), but the functional brain response to SSRIs involves neural circuits beyond regions with high 5-HTT expression. Currently, it is unclear whether and how changes in 5-HTT availability after SSRI administration modulate brain function of key serotoninergic circuits, including those characterized by high availability of the serotonin 1A receptor (5-HT1AR).

AIM

We investigated the association between 5-HTT availability and 5-HTT- and 5-HT1AR-enriched functional connectivity (FC) after an acute citalopram challenge.

METHODS

We analyzed multimodal data from a dose-response, placebo-controlled, double-blind study, in which 45 healthy women were randomized into three groups receiving placebo, a low (4 mg), or high (16 mg) oral dose of citalopram. Receptor-Enhanced Analysis of functional Connectivity by Targets was used to estimate 5-HTT- and 5-HT1AR-enriched FC from resting-state and task-based fMRI. 5-HTT availability was determined using [123I]FP-CIT single-photon emission computerized tomography.

RESULTS

5-HTT availability was negatively correlated with resting-state 5-HTT-enriched FC, and with task-dependent 5-HT1AR-enriched FC. Our exploratory analyses revealed lower 5-HT1AR-enriched FC in the low-dose group compared to the high-dose group at rest and the placebo group during the emotional face-matching task.

CONCLUSIONS

Taken together, our findings provide evidence for differential links between 5-HTT availability and brain function within 5-HTT and 5-HT1AR pathways and in context- and dose-dependent manner. As such, they support a potential pivotal role of the 5-HT1AR in the effects of citalopram on the brain and add to its potential as a therapeutic avenue for mood and anxiety disturbances.

The zebrafish for preclinical psilocybin research

In this review, we discuss the possible utility of zebrafish in research on psilocybin, a psychedelic drug whose recreational use as well as possible clinical application are gaining increasing interest. First, we review behavioral tests with zebrafish, focussing on anxiety and social behavior, which have particular relevance in the context of psilocybin research. Next, we briefly consider methods of genetic manipulations with which psilocybin's phenotypical effects and underlying mechanisms may be investigated in zebrafish. We briefly review the known mechanisms of psilocybin, and also discuss what we know about its safety and toxicity profile. Last, we discuss examples of how psilocybin may be employed for testing treatment efficacy in preclinical research for affective disorders in zebrafish. We conclude that zebrafish has a promising future in preclinical research on psychedelic drugs.

Cardiac Arrest Associated With Psilocybin Use and Hereditary Hemochromatosis

Recreational drug use is a significant public health concern in various countries. It is well understood that usage of psychedelics/hallucinogens, such as lysergic acid diethylamide (LSD), ecstasy, phencyclidine (PCP), and psilocybin-containing mushrooms, has increased significantly over the last few decades, particularly in adolescents and young adults, yet the effects of these recreational drugs are poorly understood. Psilocybin has recently been studied as an alternative to traditional antidepressant therapies with potentially benign side effects. Here, we present the case of a 48-year-old male with a past medical history of attention-deficit/hyperactivity disorder on lisdexamfetamine who presented after a syncopal episode witnessed by his wife at home. He was found to be in ventricular fibrillation and subsequently had an extensive workup with cardiac magnetic resonance imaging (MRI), ischemic evaluation, and electrophysiology, which were unrevealing. He then received an automatic implantable cardiac defibrillator and was incidentally found to have hereditary hemochromatosis on outpatient follow-up. His polypharmacy may have potentially led to catecholamine release, leading to ventricular arrhythmia.

Psychedelic medicine at a crossroads: Advancing an integrative approach to research and practice

Psychedelics have been already used by human societies for more than 3000 years, mostly in religious and healing context. The renewed interest in the potential application of psychedelic compounds as novel therapeutics has led to promising preliminary evidence of clinical benefit in some psychiatric disorders. Despite these promising results, the potential for large-scale clinical application of these profoundly consciousness-altering substances, in isolation from the sociocultural contexts in which they were traditionally used, raises important concerns. These concerns stem from the recognition that the mechanisms of therapeutic action of psychedelics are not entirely dependent on neurobiology, but also on the psychological, social and spiritual processes for their efficacy. For these reasons, physicians or psychotherapists involved in psychedelic-assisted psychotherapy need training in ways to accompany patients through this experience to promote positive outcomes and address potential side effects. Psychedelic therapies may foster the emergence of a novel paradigm in psychiatry that integrates psychopharmacological, psychotherapeutic, and cultural interventions for patients with mental health issues.

The modern clinical use of hallucinogens. What can we learn from the natural product research?

Can the emerging field of psychedelic research benefit from natural product research? We believe it can. In this manuscript we delineate certain topics of research with hallucinogens that directly connect with research on natural products in general.

Unraveling the Mysteries of Mental Illness With Psilocybin

Current medications have not been effective in reducing the prevalence of mental illness worldwide. The prevalence of illnesses such as treatment-resistant depression has increased despite the widespread use of a broad set of psychopharmaceuticals. Transcranial magnetic stimulation and ketamine therapy are making great strides in improving treatment-resistant depression outcomes but they have limitations. New psychotherapeutics are required that specifically target the underlying cellular pathologies leading to neuronal atrophy. This neuronal atrophy model is supplanting the long-held neurotransmitter deficit hypothesis to explain mental illness. Interest in psychedelics as therapeutic molecules to treat mental illness is experiencing a 21st-century reawakening that is on the cusp of a transformation. Psilocybin is a pro-drug, found in various naturally occurring mushrooms, that is dephosphorylated to produce psilocin, a classic tryptamine psychedelic functional as a 5-hydroxytryptamine 2A receptor agonist. We have focused this review to include studies in the last two years that suggest psilocybin promotes neuronal plasticity, which may lead to changes in brain network connectivity. Recent advancements in clinical trials using pure psilocybin in therapy suggest that it may effectively relieve the symptoms of depression in patients diagnosed with major depressive disorder and treatment-resistant depression. Sophisticated cellular and molecular experiments at the systems level have produced evidence that demonstrates psilocybin promotes neuritogenesis in the mouse brain - a mechanism that may address the root cause of depression at the cellular level. Finally, studies with psilocybin therapy for major depressive disorder suggest that this ancient molecule can promote functionally connected intrinsic networks in the human brain, resulting in durable improvements in the severity of depressive symptoms. Although further research is necessary, the prospect of using psilocybin for the treatment of mental illness is an enticing possibility.