The effect of a synthetic cannabinoid agonist (nabilone) on unimodal tactile illusion correlates with a psychometric scores in healthy volunteers
Scientific Reports May 27, 2025 Faiz Mohammed Kassim, Alexander J. W. Davey, Sophie Tod et al.
A synthetic cannabinoid agonist, nabilone, reduces the tactile funneling illusion—a phenomenon where two simultaneous touches on the skin are perceived as a single sensation in between. In a randomized, double-blind, placebo-controlled crossover trial with 32 healthy participants, nabilone decreased the illusion in a delay-dependent manner, particularly when stimuli were delivered simultaneously (0 ms delay). It also reduced errors in localizing touches in a distance-dependent way. The drug increased ratings on two of five psychometric scales but did not change overall scores. Associations between overall psychometric scores and the illusion under the strongest condition depended on the drug. Unlike dexamphetamine, which widens stimulus binding windows, nabilone narrows them, reducing illusory perception.