MDMA (ecstasy) increases feelings of sociability and closeness. This study tested whether those effects come from a rise in the hormone oxytocin. In 14 healthy MDMA users given MDMA, oxytocin nasal spray, or placebo, only the higher MDMA dose (1.5 mg/kg) raised blood oxytocin levels to a peak of 83.7 pg/ml around 90–120 minutes, versus 18.6 pg/ml after placebo. The higher oxytocin spray (40 IU) raised levels to 48.0 pg/ml. MDMA increased heart rate, blood pressure, and feelings of euphoria and sociability, but oxytocin spray did not. The subjective effects of MDMA were not linked to oxytocin levels, suggesting oxytocin may not be the main cause of MDMA's prosocial effects.
Low doses of LSD (13 and 26 micrograms) produced broad reductions in brain wave power across multiple frequency bands during rest and dampened specific event-related potentials (P300 and N170) during a visual task in healthy adults. The drug also increased positive mood, energy, and anxiety, as well as heart rate and blood pressure, but did not cause the full perceptual or sensory changes typical of higher psychedelic doses. These neurophysiological effects resemble those seen with higher doses, suggesting that very low LSD doses might produce subtle behavioral or therapeutic effects without inducing a full psychedelic experience.