Does Serotonin System Stimulation Increase Pro-social Behavior? - A Comparative Pharmacological Neuroscientific Study in Healthy Humans

The study looks into whether administering psychedelic substances that stimulate the serotonin system influences pro-social behavior when compared to administering substances that stimulate the dopamine system in healthy individuals. Psychedelic substances have been shown to be powerful modulators of social perception and behavior during the acute experience. This is of particular interest given that social relationships play a key role in the development and resolution of psychiatric symptoms. However, the neuropharmacological mechanism underlying pro-social effects and time-dependent changes currently remain unclear. This study therefore aims at answering two key questions: 1) Does stimulation of the serotonin system induce lasting effects on pro-social behavior? and 2) Are these effects specific to serotonergic stimulation? The following proposed study will assess these questions by investigating objective, ecologically valid measures of pro-social cognition four weeks after different pharmacological challenges (MDMA, an entactogen and releaser of serotonin, norepinephrine, and dopamine; psilocybin: a classical psychedelic and serotonin 2A receptor agonist, methylphenidate: an amphetamine and norepinephrine-dopamine re-uptake inhibitor) in healthy volunteers.