Tuning in together: LSD enhances inter-brain synchrony and felt connectedness in romantic couples
LSD increases inter-brain synchrony and feelings of connection between romantic couples
In this new randomized, double-blind, placebo-controlled crossover experimental study 25 romantic couples received either 50 μg LSD or placebo together, with the conditions separated in a randomized crossover design. EEG was recorded simultaneously from both partners (“hyperscanning”) during resting and interactive conditions
Key findings:
LSD increased subjective love, closeness, trust, feeling “in sync” and connectedness, and reduced loneliness.
The increase in connectedness persisted while subjective drug intensity and plasma LSD concentration were already declining.
During shared rest, LSD increased inter-brain synchrony, specifically theta-band amplitude-envelope coupling.
The effect was greater than the coupling observed between unrelated individuals.
Exploratory analyses suggested that couples with greater resting synchrony reported greater connectedness
The study measured an acute subjective state and a neural coupling measure. Note that long term relationship quality was not assessed
Abstract
Social connection is fundamental to human wellbeing. Serotonergic psychedelics such as lysergic acid diethylamide (LSD) acutely heighten subjective connectedness, yet their effects on real-time social connection remain poorly understood.
Using EEG hyperscanning in a randomized, double-blind, placebo-controlled crossover study, we recorded neural activity simultaneously from both members of healthy romantic couples (N=25) who received LSD (50 μg) or placebo together, across resting and interactive states. LSD increased subjective connectedness, including feelings of love, closeness, trust, and being “in sync,” while reducing loneliness, compared to placebo.
This affiliative shift dissociated from the drug’s pharmacokinetic time-course, remaining elevated as subjective intensity and plasma concentration declined. In parallel, LSD increased inter-brain synchrony during shared rest, carried specifically by theta-band amplitude-envelope coupling. Importantly, this effect survived two complementary controls.
First, it exceeded coupling between unrelated individuals and second the effects depended on contemporaneous neural alignment rather than shared drug-induced dynamics. Exploratory analyses showed that romantic partners with greater resting synchrony reported greater feelings of connectedness. These findings provide the first evidence that a psychedelic enhances brain-to-brain coupling between people, linking a pharmacologically induced state of felt connection to a measurable signature shared across interacting brains.
Mason NL, Czeszumski A, Totomanova I, Trbusek F, Cavarra M, Ashton SM, Toennes SW, Theunissen E, Reckweg JT, Lockwood PL, DeWitte M, Preller KH, Kuypers KPC, Dumas G, Mallaroni P, Ramaekers J. Tuning in together: LSD enhances inter-brain synchrony and felt connectedness in romantic couples. bioRxiv. 2026. doi:10.64898/2026.08.13.744639 Read Paper
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