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Marcus W Meinhardt

Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany. marcus.meinhardt@zi-mannheim.de.

5 papers in the library · 18 citations · publishing 2024-2026

Papers

A new module in the drug development process: preclinical multi-center randomized controlled trial of R-ketamine on alcohol relapse.

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology May 1, 2025 Marcus W Meinhardt, Ivan Skorodumov, Jérôme Jeanblanc et al. 8 citations

A new approach in psychiatric drug development, the preclinical randomized controlled trial (preRCT), was tested across three European centers using a rat model of alcohol relapse. Ketamine (20 mg/kg) reduced relapse, while R-ketamine worked only in females at the same dose; a higher dose (40 mg/kg) was effective in males. The sex-dependent effects were linked to plasma R-ketamine levels, which were twice as high in females. R-ketamine produced a lasting reduction in alcohol consumption without adverse effects. The findings support moving to a clinical trial that accounts for sex differences.

Prefrontal electrophysiological biomarkers and mechanism-based drug effects in a rat model of alcohol addiction.

Translational psychiatry December 5, 2024 Bettina Habelt, Dzmitry Afanasenkau, Cindy Schwarz et al. 6 citations

Alcohol use disorder (AUD) impairs prefrontal control mechanisms, leading to reduced inhibitory control and increased relapse risk. Using a biocompatible neuroprosthesis in a rat model of alcohol addiction, researchers measured neural oscillations and event-related potentials during abstinence. Alcohol-dependent rats showed reduced amplitudes of P1N1 and N1P2 components and attenuated event-related oscillatory activity, along with a dominance in higher beta frequencies indicating hyperarousal prone to relapse. Treatment with psilocybin or LY379268 restored these electrophysiological impairments, with psilocybin particularly counteracting the hyperarousal state. These prefrontal markers may serve as indicators of relapse vulnerability and treatment response, especially for psychedelic drugs.

Psilocin fosters neuroplasticity in iPSC-derived human cortical neurons.

eLife March 27, 2026 Malin Schmidt, Anne Hoffrichter, Mahnaz Davoudi et al. 3 citations

Psilocin, the psychoactive metabolite of psilocybin, increases BDNF abundance in human cortical neurons derived from induced pluripotent stem cells via the 5-HT2A receptor. Transcriptomic profiling shows gene expression changes that prime neurons for neuroplasticity. Morphologically, psilocin enhances neuronal complexity and increases synaptic proteins, especially in the postsynaptic compartment. Functionally, it leads to increased excitability and enhanced synaptic network activity. These findings suggest psilocin induces a state of enhanced neuronal plasticity, which may explain its therapeutic potential in neuropsychiatric disorders involving synaptic dysfunction.

Epigenome-wide association study of psilocybin-induced methylome changes in alcohol use disorder.

Translational psychiatry May 26, 2026 Marvin M Urban, Lea Zillich, Nathalie M Rieser et al. 1 citation

In a pilot study of 37 detoxified patients with alcohol use disorder, psilocybin (25 mg) produced changes in DNA methylation across the genome compared to placebo. One methylation site in the TLE4 gene and a differentially methylated region in RASGRP4 were linked to psilocybin treatment. Co-methylation networks related to psilocybin were associated with reductions in depressive symptoms and drinking behavior, and gene analysis pointed to involvement in neuroplasticity and immune functions. The primary trial endpoints—duration of abstinence and mean alcohol use—were not reached, so the analysis focused on secondary psychometrics. The findings suggest immunomodulatory actions of psilocybin but are limited by the modest sample size.

(R)-Ketamine reduces alcohol intake and alcohol seeking induced by reconsolidation of alcohol-related memories in female Marchigian Sardinian alcohol-preferring rats.

Psychopharmacology November 15, 2025 Elisabetta Ciccocioppo, Sara Massetti, Marcus W Meinhardt et al.

Alcohol use disorder (AUD) is a major medical problem with limited treatments. (R)-ketamine, a form of the dissociative psychedelic with fewer dissociative and anesthetic effects than the racemic mixture, reduced alcohol consumption in female but not in male Marchigian Sardinian alcohol-preferring (msP) rats when given orally at doses of 10, 20, and 40 mg/kg in a two-bottle free choice 24-hour drinking paradigm. No effect was observed on alcohol self-administration. (R)-ketamine also attenuated the retrieval of alcohol-related memories in female but not in male rats. These results suggest (R)-ketamine attenuates alcohol-related behaviors in a sex-dependent manner, with females showing higher sensitivity, supporting clinical investigation in patients with AUD.