Biological Psychiatry
April 26, 2014
Rainer Kraehenmann, Katrin H. Preller, Milan Scheidegger et al.
325 citations
A double-blind, randomized, crossover study in 25 healthy volunteers found that a single dose of psilocybin (0.16 mg/kg) reduced amygdala reactivity to negative and neutral stimuli, measured with functional magnetic resonance imaging, compared with placebo. The reduction in right amygdala reactivity to negative stimuli was linked to an increase in positive mood, assessed with the Positive and Negative Affect Schedule and the State-Trait Anxiety Inventory. These findings suggest psilocybin may dampen neural responses to negative emotional cues and improve mood, which could be relevant for treating conditions like major depression where amygdala hyperactivity and negative mood states are common.
Frontiers in Pharmacology
November 8, 2017
Rainer Kraehenmann, Dan Pokorný, Helena Aicher et al.
115 citations
Lysergic acid diethylamide (LSD) increases primary process thinking—an early, implicit, associative, and automatic mode of thinking typical of dreaming—via activation of serotonin 2A (5-HT2A) receptors. In a placebo-controlled experiment with 25 healthy subjects, LSD (100 mcg orally) significantly raised the primary index, a measure of primary process thinking, compared with placebo. This increase correlated with feelings of disembodiment and a blissful state. Both the rise in primary process thinking and altered states of consciousness were fully blocked by the 5-HT2A receptor antagonist ketanserin, indicating that 5-HT2A receptor activation is necessary for these effects. Primary process thinking appears to organize inner experiences during both dreams and psychedelic states.
Frontiers in Psychiatry
August 18, 2017
Zurina Hassan, Oliver G. Bosch, Darshan Singh et al.
62 citations
Human culture involves learning to consume natural or synthetic psychoactive compounds that alter mental states and behavior. After a novel psychoactive substance (NPS) emerges and is experimentally used, its benefits and harms can be estimated, leading to legal classifications ranging from medical use to complete bans. However, banned drugs often continue to be used, allowing better understanding of their properties, and views on a drug can shift from harmful to medically useful. This review summarizes recent neuropharmacological progress on several NPS, including mitragynine, synthetic cannabinoids, dimethyltryptamine, novel serotonergic hallucinogens, cathinones, ketamine, novel dissociatives, gamma-hydroxybutyrate, gamma-butyrolactone, and 1,4-butanediol, highlighting both emerging harm potentials and potential medical applications.
British Journal of Clinical Pharmacology
December 11, 2015
Matthias E. Liechti, Boris B. Quednow, Evangelia Liakoni et al.
57 citations
Gamma-hydroxybutyrate (GHB) produced mixed stimulant-sedative effects in healthy men, with higher doses causing more sedation and dizziness but no changes in heart rate or blood pressure. Plasma exposure to GHB rose disproportionately with dose—a 40% greater increase than expected from dose alone—indicating nonlinear pharmacokinetics. The psychotropic effects were closely tied to plasma concentrations, and no acute tolerance developed over time.
Psychoneuroendocrinology
July 17, 2015
Oliver G. Bosch, Christoph Eisenegger, Jürg Gertsch et al.
42 citations
Gamma-hydroxybutyrate (GHB), a GHB-/GABAB-receptor agonist, produces euphoric, disinhibiting, and vitality-enhancing effects in healthy men. In a randomized, placebo-controlled crossover trial with 16 males, a single 20 mg/kg dose increased charitable donations and prosocial money distributions among participants who initially showed low prosociality. However, GHB did not alter emotion recognition, empathy, theory-of-mind, or basic cognitive functions. The drug raised plasma progesterone levels but left oxytocin, testosterone, cortisol, aldosterone, DHEA, and ACTH unchanged. These findings suggest that GHB's mood and prosocial effects may involve GHB-/GABAB-receptors and progesterone rather than typical social hormones like oxytocin or testosterone.
European Neuropsychopharmacology
December 4, 2014
Yasmin Schmid, Cédric M. Hysek, Katrin H. Preller et al.
39 citations
In a double-blind, placebo-controlled crossover study with 30 healthy adults, a single 40 mg dose of methylphenidate increased subjective ratings of sexual arousal when viewing explicit erotic pictures and led participants to press a button to prolong viewing of implicit sexual stimuli, whereas a 75 mg dose of MDMA did not alter sexual arousal. Neither drug changed how participants appraised the romantic relationships of unknown couples. Blood levels of testosterone, estrogen, and progesterone were unrelated to arousal ratings. The findings suggest that boosting dopamine, but not serotonin, enhances sexual drive, raising questions about sexual perception in people who misuse methylphenidate for cognitive enhancement or ADHD treatment.
International Journal of Bipolar Disorders
July 5, 2022
Oliver G. Bosch, Simon Halm, Erich Seifritz
35 citations
Classic psychedelics such as LSD, psilocybin, mescaline, and ayahuasca are being studied again for treating unipolar and bipolar depression. They alter sensory perception, emotion, and self-processing by stimulating serotonin 2A receptors in the brain. Psychedelic-assisted psychotherapy integrates a safe psychedelic experience into ongoing therapy. Early randomized trials with psilocybin show promising results for unipolar depression, but classic psychedelics may also trigger mania. Atypical psychedelics like MDMA and ketamine work through different mechanisms; esketamine is approved for treatment-resistant unipolar depression, and ketamine shows early evidence for bipolar depression. Larger trials and careful legal frameworks will determine their broader clinical use.
PLoS ONE
April 9, 2013
Oliver G. Bosch, Michael Wagner, Frank Jessen et al.
34 citations
Recreational users of MDMA show verbal learning and recall deficits that are linked to reduced glucose metabolism in the prefrontal and parietal cortex, and word recognition difficulties are additionally associated with reduced metabolism in the mediotemporal region. These findings indicate that memory problems in MDMA users result from combined dysfunction across frontal, parietal, and mediotemporal brain areas.
European Neuropsychopharmacology
March 8, 2017
Oliver G. Bosch, Michael M. Havranek, A Baumberger et al.
22 citations
Gamma-hydroxybutyrate (GHB), a drug used for narcolepsy and abused recreationally, has prosexual effects in healthy men. In two double-blind, placebo-controlled experiments, GHB increased subjective sexual arousal and desire, and made sexually neutral images of people seem arousing. Brain scans showed that GHB boosted activity in reward regions like the nucleus accumbens when viewing erotic pictures, and increased connectivity between the nucleus accumbens and the ventromedial prefrontal cortex. The findings indicate GHB enhances hedonic sexual functioning and lowers the threshold for perceiving erotic cues by sensitizing mesolimbic reward pathways.
Psychopharmacology
July 1, 2017
Robin Rotz, Michael Kometer, Dario Dornbierer et al.
19 citations
Gamma-hydroxybutyrate (GHB) increases theta oscillations in the posterior cingulate cortex and alpha1 oscillations in the anterior cingulate cortex, while decreasing the global omega complexity of alpha1 oscillations. Higher blood plasma levels of GHB are linked to increased delta oscillation connectivity between the posterior cingulate cortex and the right inferior parietal lobulus. These neural changes in the posterior cingulate cortex may explain the paradoxical dissociation between EEG patterns and behavior that GHB produces, where brain activity resembles sleep during wakefulness. The reduced number of independent neuronal processes is similar to effects seen with other anesthetics.