Last updated on June 28, 2026 · Originally published June 23, 2026
Thousands of people have received psilocybin in controlled research settings over the past several decades. According to a 2024 review, fewer than 1.4% of them were older adults.
That’s a striking gap for a compound whose proposed mechanisms — promoting neuroplasticity, reducing rumination, supporting emotional regulation — overlap substantially with what researchers know about healthy aging. A new study at UC Berkeley is designed to address it directly.
Launched earlier this year, the PLASTICITY trial (Psychedelic Longitudinal Aging Study In Cognitively Healthy Older Adults) is the first psychedelic neuroimaging study specifically focused on older adults. Participants between 60 and 85 years old will receive synthetic psilocybin in a controlled setting, with comprehensive cognitive, perceptual, and brain imaging assessments taken before the experience, one week after, and one month after.
The imaging protocol is more detailed than most psychedelics studies. Diffusion MRI will be used to examine the microstructure of the hippocampus — the brain region central to memory and learning — while functional MRI will track changes in brain activity during memory encoding and retrieval. The study will also measure vagus nerve activity, a physiological marker linked to stress recovery, to explore whether psilocybin-associated changes in emotional states have detectable downstream effects on the nervous system.
The scientific rationale draws on animal work showing that psilocybin increases synaptic density in the hippocampus and prefrontal cortex. Whether that effect translates to humans — and specifically to older humans whose baseline brain structure is already changing — is the central question. “One of the things I am most interested in is seeing whether we can actually measure those potentially beneficial brain changes in older adults,” said Tyler Toueg, a UC Berkeley doctoral student in neuroscience who co-led the study’s design.
The interdisciplinary team spans neuroscience, psychology, psychiatry, and aging research, including Professor William Jagust, a leading Alzheimer’s disease researcher, and Professor Dacher Keltner, whose work on awe and well-being informs part of the study’s subjective assessment battery.
PLASTICITY runs alongside a larger federal investment in the same question. The NIH-funded INSPIRE Network — a $21 million, multi-site program specifically dedicated to psychedelic research in adults 65 and older — is enrolling at sites including Emory University, with Phase I focused on safety and physiological indicators in healthy older participants.
Results from either study are likely years away. But the shift in research focus is itself meaningful: after decades of trials that skewed young, a field built on the promise of brain plasticity is finally looking at the population that may need it most.
Sources: Berkeley News, “Tripping into old age: Can psychedelics protect the aging brain?” June 8, 2026. Emory University News, “Emory joins landmark $21 million NIH study of psychedelics
