Background: Reduced Environmental Stimulation Therapy via floatation (floatation-REST) is a behavioral intervention designed to attenuate exteroceptive sensory input to the nervous system. Pilot studies in anxious and depressed individuals demonstrated that single sessions of floatation-REST are safe, well-tolerated, and associated with acute anxiolysis. However, there is not sufficient evidence of the feasibility of floatation-REST as a repeated intervention. Methods: We randomized 75 individuals with anxiety and depression to six sessions of floatation-REST in different formats (pool-REST or pool-REST preferred) or an active comparator (chair-REST). Feasibility was assessed via adherence rate to the assigned intervention, tolerability via duration of REST utilization and overall study dropout rate, and safety via incidence of serious or non-serious adverse events. Results: Six-session adherence was 85% for pool-REST, 89% for pool-REST preferred, and 74% for chair-REST. Dropout rates did not differ significantly between the treatment conditions. Mean session durations were consistently above 50 minutes, and when allowed to choose the duration and frequency, participants opted to float for an average of 75 minutes. There were no serious adverse events associated with any intervention. Positive experiences were endorsed more commonly than negative ones and were also rated at higher levels of intensity. Conclusions: Taken together, six sessions of floatation-REST appear feasible, well-tolerated, and safe in anxious and depressed individuals. Floatation-REST induces positively-valenced experiences with few negative effects. warrant further investigation of clinical efficacy. Larger randomized controlled trials evaluating markers of clinical efficacy are warranted. Clinical Trial Registration Identifier: NCT03899090

The authors have declared no competing interest.

ClinicalTrials.gov NCT03899090

https://clinicaltrials.gov/ct2/show/NCT03899090

This research was supported by an award from the National Center for Complimentary and Integrative Health (R34AT009889). The authors were also supported by the National Institute of Mental Health (R01MH127225, K23MH112949 to SSK), National Institute of General Medical Sciences Center Grant Award Number (1P20GM121312 to MPP, JSF, SSK), and The William K. Warren Foundation. The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication.

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All study procedures were approved by the Western Institutional Review Board (Protocol #: 20150528) and were performed in accordance with Declaration of Helsinki. All participants provided their written informed consent prior to participation and were compensated for their study involvement.

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