Stroboscopic Light Stimulation in Adults Reporting Depressive Symptoms: Safety, Tolerability, Feasibility, and Active-Comparator Development in a Staged Early-Phase Study
- 1Sussex Centre for Consciousness Science and School of Engineering and Informatics, University of Sussex, UK
Abstract
Stroboscopic light stimulation (SLS) is a candidate non-pharmacological intervention that induces transient visual and affective experiences, with potential application in depression. Before efficacy testing, clinical development requires safety, tolerability, and feasibility data. We report a staged, single-site programme in adults reporting depressive symptoms. Study 1 tested 11 SLS parameter sets for safety and tolerability. Study 2 assessed whether an active comparator reduced subjective visual effects while preserving session context. Study 3 randomised 84 participants to four weekly supervised 31-minute sessions of strobe-emphasis or wash-emphasis SLS. In Study 1, 31 participants were analysed; no severe adverse reactions occurred, mean discomfort was low (0.49/10), and the highest session-level upper 80% confidence limit was 1.13/10, well below the prespecified threshold. Study 2 supported within-participant experiential separation between the two SLS configurations in healthy adults. In Study 3, endpoint data were available for 70/84 randomised participants (83.3%): 39/42 assigned to strobe-emphasis and 31/42 assigned to wash-emphasis. Discomfort remained low, with no serious SLS-attributable adverse events. Both configurations produced visual phenomenology in the Study 3 target sample, and the phenomenological separation observed during Study 2 was not reproduced between groups in Study 3. The comparison estimates differences between two active SLS configurations, rather than SLS versus no stimulation. Exploratory depressive-symptom estimates were imprecise, limited by differential endpoint availability, and should inform endpoint selection and subsequent trial design rather than efficacy. Overall, the programme supports further controlled evaluation of supervised SLS while identifying experiential separation, retention, masking, and endpoint selection as priorities for the next trial.
Related
- Stroboscopic light stimulation as a controllable probe of the psilocybin state: a mechanistic framework and a falsifiable prediction
- Sublingual Buprenorphine/Naloxone Film in Unanesthetized Rats: Feasibility, Tolerability, and Plasma Exposure
- Statistical analysis plan for the feasibility trial assessing external trigeminal nerve stimulation versus sham stimulation for ADHD in children and adolescents aged 7 to 17 years (the eTNS4ADHD trial)
- Music-Synchronized Gamma Light Stimulation Strengthens Theta-Gamma Coupling in Older Adults with Cognitive Impairment: Results from a Randomized Feasibility Trial
- Chronic sensing during subcallosal cingulate deep brain stimulation captures ketamine-associated changes in major depressive disorder
BibTeX
@misc{nacker2026stroboscopic,
title = {{Stroboscopic Light Stimulation in Adults Reporting Depressive Symptoms: Safety, Tolerability, Feasibility, and Active-Comparator Development in a Staged Early-Phase Study}},
author = {D. Nacker and L. Kalus and A. K. Seth and J. M. Stone and R. C. Ciure and G. Lawson and J. Simpson and J. W. Sander and s. bremner and C. I. Jones and W. Wood and F. Macpherson and D. Proeckl and E. Winkler and D. J. Schwartzman},
howpublished = {medRxiv},
year = {2026},
month = jun,
doi = {10.64898/2026.06.17.26355864},
url = {https://www.medrxiv.org/content/10.64898/2026.06.17.26355864v3},
note = {CC BY},
}
RIS
TY - UNPB
TI - Stroboscopic Light Stimulation in Adults Reporting Depressive Symptoms: Safety, Tolerability, Feasibility, and Active-Comparator Development in a Staged Early-Phase Study
AU - D. Nacker
AU - L. Kalus
AU - A. K. Seth
AU - J. M. Stone
AU - R. C. Ciure
AU - G. Lawson
AU - J. Simpson
AU - J. W. Sander
AU - s. bremner
AU - C. I. Jones
AU - W. Wood
AU - F. Macpherson
AU - D. Proeckl
AU - E. Winkler
AU - D. J. Schwartzman
PY - 2026
DA - 2026/06/17
PB - medRxiv
DO - 10.64898/2026.06.17.26355864
UR - https://www.medrxiv.org/content/10.64898/2026.06.17.26355864v3
AB - Stroboscopic light stimulation (SLS) is a candidate non-pharmacological intervention that induces transient visual and affective experiences, with potential application in depression. Before efficacy testing, clinical development requires safety, tolerability, and feasibility data. We report a staged, single-site programme in adults reporting depressive symptoms. Study 1 tested 11 SLS parameter sets for safety and tolerability. Study 2 assessed whether an active comparator reduced subjective visual effects while preserving session context. Study 3 randomised 84 participants to four weekly supervised 31-minute sessions of strobe-emphasis or wash-emphasis SLS. In Study 1, 31 participants were analysed; no severe adverse reactions occurred, mean discomfort was low (0.49/10), and the highest session-level upper 80% confidence limit was 1.13/10, well below the prespecified threshold. Study 2 supported within-participant experiential separation between the two SLS configurations in healthy adults. In Study 3, endpoint data were available for 70/84 randomised participants (83.3%): 39/42 assigned to strobe-emphasis and 31/42 assigned to wash-emphasis. Discomfort remained low, with no serious SLS-attributable adverse events. Both configurations produced visual phenomenology in the Study 3 target sample, and the phenomenological separation observed during Study 2 was not reproduced between groups in Study 3. The comparison estimates differences between two active SLS configurations, rather than SLS versus no stimulation. Exploratory depressive-symptom estimates were imprecise, limited by differential endpoint availability, and should inform endpoint selection and subsequent trial design rather than efficacy. Overall, the programme supports further controlled evaluation of supervised SLS while identifying experiential separation, retention, masking, and endpoint selection as priorities for the next trial.
ER -