Pharmacokinetics and Pharmacodynamics of an Innovative Psychedelic N,N-Dimethyltryptamine/Harmine Formulation in Healthy Participants: A Randomized Controlled Trial.

Background: Recent interest in the clinical use of psychedelics has highlighted plant-derived medicines like ayahuasca showing rapid-acting and sustainable therapeutic effects in various psychiatric conditions. This traditional Amazonian plant decoction contains N,N-dimethyltryptamine (DMT) and β-carboline alkaloids such as harmine. However, its use is often accompanied by distressing effects like nausea, vomiting, and intense hallucinations, possibly due to complex pharmacokinetic/pharmacodynamic (PK-PD) interactions and lack of dose standardization.

No evidence for an association of testosterone and cortisol hair concentrations with social decision-making in a large cohort of young adults.

Prior research has established that testosterone is an important modulator of social decision-making. However, evidence on the relationship between basal testosterone levels, commonly measured in saliva or blood, and social behavior has been inconsistent due to methodological shortcomings. Additionally, it has been suggested that cortisol might moderate the association between basal testosterone and social behavior.

The effects of single testosterone administration and stress induction on steroid hormone levels in hair.

Hair steroid analysis is increasingly recognized for its ability to capture cumulative hormone secretion, thought to reflect an individual's response to long-term environmental conditions. Despite its growing use, the influence of single, isolated events on hair steroid concentrations remains underexplored. Our study therefore examined the effects of a single-dose transdermal testosterone administration (150 mg) and acute laboratory stress induction on hair testosterone and cortisol levels in a randomized, between-subject, placebo-controlled, and double-blind design.

Words versus Strands: Reliability and Stability of Concordance Rates of Self-Reported and Hair-Analyzed Substance Use of Young Adults over Time.

Introduction: Population-level substance use research primarily relies on self-reports, which often underestimate actual use. Hair analyses offer a more objective estimate; however, longitudinal studies examining concordance are lacking. Previous studies showed that specific psychological and behavioral characteristics are associated with a higher likelihood of underreporting substance use, but the longitudinal stability of these associations remains unclear.

Associations Between Self-Reported Cocaine Use Patterns and Cocaine and Its Metabolites in Hair: Implications for Clinical and Forensic Practices.

In forensic toxicology, it has been debated if hair testing allows an estimation of the intensity of cocaine use-an assumption that may have risen because self-reports in a forensic setting are of uncertain validity per se. We therefore investigated the relationship between self-reported cocaine use and cocaine hair concentrations (including its main metabolites benzoylecgonine and norcocaine) in chronic cocaine users voluntary participating in psychiatric study settings. Additionally, we tested whether hair testing can distinguish between individuals with and without a diagnosis of cocaine dependency.

Forget me not: The effect of doxycycline on human declarative memory.

Investigations into neuroprotective drugs are in high demand for the treatment of neurodegenerative diseases, such as multiple sclerosis or Alzheimer's disease, but also psychiatric disorders, such as depression, trauma, and substance use. One potential drug class being investigated are tetracyclines impacting on a variety of neuroprotective mechanisms. At the same time, tetracyclines like doxycycline have been suggested to affect human fear and spatial memory as well as reducing declarative memory retention.

[Psychedelic and dissociative agents in psychiatry: challenges in the treatment].

With the discovery of the antidepressive effects of ketamine and the increasing withdrawal of the pharmaceutical industry from the development of new psychotropic drugs, the psychiatric research into the clinical application of hallucinogens in psychiatry has literally blossomed in the last two decades. Promising results for various treatment approaches with psychedelic agents, such lysergic acid diethylamide (LSD) and psilocybin, and dissociative agents, such as ketamine and esketamine, have raised great hopes among researchers, clinicians and patients in recent years, so that there was already talk of a new era in psychiatry. As one of the first of these substances, in December 2019 intranasal esketamine was approved in the USA and the EU for the treatment of treatment-resistant depression and Switzerland followed in 2020.

Disentangling the effects of self-control and the use of tobacco and cannabis on violence perpetration from childhood to early adulthood.

Associations among self-control, substance use (e.g., tobacco and cannabis use), and violence perpetration have been documented during the adolescent years, but the direction of these associations is not well understood.

Plasma neurofilament light, glial fibrillary acid protein, and phosphorylated tau 181 as biomarkers for neuropsychiatric symptoms and related clinical disease progression.

Background: Neuropsychiatric symptoms (NPS) are common in older people, may occur early in the development of dementia disorders, and have been associated with faster cognitive decline. Here, our objectives were to investigate whether plasma levels of neurofilament light chain (NfL), glial fibrillary acid protein (GFAP), and tau phosphorylated at threonine 181 (pTau181) are associated with current NPS and predict future NPS in non-demented older people. Furthermore, we tested whether the presence of NPS combined with plasma biomarkers are useful to predict Alzheimer's disease (AD) pathology and cognitive decline.

Substance Use-Related Alterations of Social Decision Making in a Longitudinal Cohort of Young Adults.

Background: Substance use disorders are associated with severe negative social and health-related outcomes. Evidence has accumulated that long-term substance use is associated with alterations in social interaction behavior, which likely contributes to the vicious cycle of substance use disorder. However, little is known about whether these social problems originate from contextual factors only or also from the substance use itself-in other words, if they are predisposed or substance induced.

Endocannabinoids and related lipids linked to social exclusion in individuals with chronic non-medical prescription opioid use.

Opioid-related overdose deaths are still on the rise in North America, emphasizing the need to better understand the underlying neurobiological mechanisms regarding the development of opioid use disorder (OUD). Recent evidence from preclinical and clinical studies indicate that the endocannabinoid system (ECS) may play a crucial role in stress and reward, both involved in the development and maintenance of substance use disorders. Animal models demonstrate a specific crosstalk between the ECS and the endogenous opioid system.

Chemical cousins with contrasting behavioural profiles: MDMA users and methamphetamine users differ in social-cognitive functions and aggression.

Methamphetamine (METH, "Crystal Meth") and 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") share structural-chemical similarities but have distinct psychotropic profiles due to specific neurochemical actions. Previous research has suggested that their impact on social cognitive functions and social behaviour may differ significantly, however, direct comparisons of METH and MDMA users regarding social cognition and interaction are lacking. Performances in cognitive and emotional empathy (Multifaceted Empathy Test) and emotion sensitivity (Face Morphing Task), as well as aggressive social behaviour (Competitive Reaction Time Task) were assessed in samples of n = 40 chronic METH users, n = 39 chronic MDMA users and n = 86 stimulant-naïve controls (total N = 165).

Higher paracetamol levels are associated with elevated glucocorticoid concentrations in hair: findings from a large cohort of young adults.

Paracetamol is one of the most commonly used over-the-counter medications. Experimental studies suggest a possible stress-suppressing effect of paracetamol in humans facing experimental stress-inducing paradigms. However, no study has investigated whether paracetamol and steroid hormones covary over longer time frames and under real-life conditions.

Plasma neurofilament light, glial fibrillary acid protein, and phosphorylated tau 181 as biomarkers for neuropsychiatric symptoms and related clinical disease progression.

Background: Neuropsychiatric symptoms (NPS) are common in older people, may occur early in the development of dementia disorders, and have been associated with faster cognitive decline. Here, our objectives were to investigate whether plasma levels of neurofilament light chain (NfL), glial fibrillary acid protein (GFAP), and tau phosphorylated at threonine 181 (pTau181) are associated with current NPS and predict future NPS in non-demented older people. Furthermore, we tested whether the presence of NPS combined with plasma biomarkers are useful to predict Alzheimer's disease (AD) pathology and cognitive decline.

Introducing neurofilament light chain measure in psychiatry: current evidence, opportunities, and pitfalls.

The recent introduction of new-generation immunoassay methods allows the reliable quantification of structural brain markers in peripheral matrices. Neurofilament light chain (NfL), a neuron-specific cytoskeletal component released in extracellular matrices after neuroaxonal impairment, is considered a promising blood marker of active brain pathology. Given its sensitivity to a wide range of neuropathological alterations, NfL has been suggested for the use in clinical practice as a highly sensitive, but unspecific tool to quantify active brain pathology.

Conflict monitoring and emotional processing in 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine users - A comparative neurophysiological study.

In stimulant use and addiction, conflict control processes are crucial for regulating substance use and sustaining abstinence, which can be particularly challenging in social-affective situations. Users of methamphetamine (METH, "Ice") and 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") both experience impulse control deficits, but display different social-affective and addictive profiles. We thus aimed to compare the effects of chronic use of the substituted amphetamines METH and MDMA on conflict control processes in different social-affective contexts (i.

Plasma endocannabinoids in cocaine dependence and their relation to cerebral metabotropic glutamate receptor 5 density.

Animal models indicate that the endocannabinoid system (ECS) plays a modulatory role in stress and reward processing, both crucially impaired in addictive disorders. Preclinical findings showed endocannabinoid-modulated synaptic plasticity in reward brain networks linked to the metabotropic-glutamate-5 receptor (mGluR5), contributing to drug-reinforcing effects and drug-seeking behavior. Although animal models postulate a link between ECS and cocaine addiction, human translational studies are lacking.

A pilot study of cerebral metabolism and serotonin 5-HT receptor occupancy in rats treated with the psychedelic tryptamine DMT in conjunction with the MAO inhibitor harmine.

The psychedelic effects of the traditional Amazonian botanical decoction known as ayahuasca are often attributed to agonism at brain serotonin 5-HT receptors by -dimethyltryptamine (DMT). To reduce first pass metabolism of oral DMT, ayahuasca preparations additionally contain reversible monoamine oxidase A (MAO-A) inhibitors, namely β-carboline alkaloids such as harmine. However, there is lacking biochemical evidence to substantiate this pharmacokinetic potentiation of DMT in brain via systemic MAO-A inhibition.

Substance use in sexual minority youth: prevalence in an urban cohort.

Background: Little comparative data on substance use (SU) between sexual minority youth (SMY) and heterosexual youth (HET) is available. This study compares the prevalence of SU in an urban cohort between SMY and HET and evaluates demographic and psychosocial predictors of SU.

Methods: Data came from a prospective-longitudinal cohort study in an urban setting (N = 1297).

Associations of psychoactive substances and steroid hormones in hair: Findings relevant to stress research from a large cohort of young adults.

Objective: Epidemiological studies increasingly use hair samples to assess people's cumulative exposure to steroid hormones, but how the use of different psychoactive substances may affect steroid hormone levels in hair is, so far, largely unknown. The current study addresses this gap by establishing the substance exposure correlates of cortisol, cortisone, and testosterone in hair, while also accounting for a number of relevant covariates.

Method: Data came from a large urban community-sample of young adults with a high prevalence of substance use (N = 1002, mean age=20.

Acetylcholine and noradrenaline enhance foraging optimality in humans.

Foraging theory prescribes when optimal foragers should leave the current option for more rewarding alternatives. Actual foragers often exploit options longer than prescribed by the theory, but it is unclear how this foraging suboptimality arises. We investigated whether the upregulation of cholinergic, noradrenergic, and dopaminergic systems increases foraging optimality.

Gamma-Aminobutyric Acid and Glutamate Concentrations in the Striatum and Anterior Cingulate Cortex Not Found to Be Associated with Cognitive Flexibility.

Behavioral flexibility and goal-directed behavior heavily depend on fronto-striatal networks. Within these circuits, gamma-aminobutyric acid (GABA) and glutamate play an important role in (motor) response inhibition, but it has remained largely unclear whether they are also relevant for cognitive inhibition. We hence investigated the functional role of these transmitters for cognitive inhibition during cognitive flexibility.