Aquahenosis: A non-pharmacological altered state of consciousness induced by Floatation-REST in individuals with anxiety and depression

Floatation-REST (Reduced Environmental Stimulation Therapy) systematically alters sensory and bodily input by combining neutral buoyancy, thermal and proprioceptive neutrality, attenuation of exteroceptive stimulation, and enhancement of cardiorespiratory signaling to the brain. Here we examined whether this non-pharmacological sensory perturbation induces altered states of consciousness and whether specific experiential dimensions are statistically related to changes in affect. In a secondary analysis of a randomized controlled feasibility trial, 75 treatment-seeking adults with anxiety and depression were assigned to six sessions of Floatation-REST with prescribed scheduling, Floatation-REST with preferred scheduling and duration, or a zero-gravity chair comparison condition. Altered states of consciousness were assessed using the 5-Dimensional Altered States of Consciousness Rating Scale, alongside measures of interoceptive awareness and affect. Compared to the chair condition, Floatation-REST was associated with increased interoceptive awareness of cardiorespiratory sensations and an altered state of consciousness characterized by Oceanic Boundlessness, Disembodiment, and Experience of Unity-a pattern we refer to as "aquahenosis." Effects were strongest among participants who selected longer and more flexible float sessions. Experiential profiles selectively overlapped with those reported for psilocybin and ketamine along boundary-dissolution dimensions. These findings identify Floatation-REST as a tractable, non-pharmacological method for inducing specific altered states of consciousness and highlight oceanic boundlessness as an important mediator of the float-induced changes in positive affect.