Fig 1.
Flow diagram for study recruitment.
Table 1.
Inclusion and exclusion criteria.
Table 2.
Participant demographics and baseline functioning on the day of Floatation-REST.
Fig 2.
Floatation-REST in an open circular float pool.
The circular fiberglass pool is 8 feet in diameter and contains 11 inches of reverse osmosis water saturated with ~1,800 pounds of USP grade Epsom salt (magnesium sulfate), creating a dense salt water solution that is maintained at a specific gravity of ~1.26, allowing participants to effortlessly float on their back while the water hovers just above the ears. A small blue LED light remains illuminated throughout the float session, and can be turned off by the participant through a round air switch (both of which can be seen in the picture, located immediately adjacent to the participant’s right foot). Unlike the picture, clothing is usually not worn while floating since anything touching the body can generate somatosensory stimulation, potentially detracting from the float experience.
Fig 3.
After the float session, participants completed a 43-item side effect checklist. For each item participants selected one of four choices (None, Mild, Moderate, or Extreme) and each choice was automatically scored as a number (0, 1, 2, or 3). Shown here is the average score across the group of 50 anxious and depressed participants, with error bars representing the standard error of the mean (SEM).
Fig 4.
Impact of Floatation-REST on state anxiety.
(A) The float experience caused a reduction in state anxiety that was evident across all 50 participants, leading to a significant pre- to post-float change on the Spielberger State Anxiety Inventory (STAI) at the group level [t(49) = -15.16, p < .0001, d = 2.15]. (B) Despite a large baseline difference, the anxious group’s average post-float anxiety had reached levels slightly lower than the pre-float anxiety reported by the non-anxious reference sample. Error bars represent the SEM.
Fig 5.
Impact of Floatation-REST on mood and affect.
Change scores from pre- to post-float are shown for all 16 measures. To facilitate comparisons across measures the score for each measure was converted to POMP units representing the percent of maximum possible on each scale. All measures showed a significant pre- to post-float change with the significance level denoted with asterisks. Error bars represent the SEM.
Fig 6.
Estimated effect size of a single float session in patients with anxiety and depression.
The estimated Cohen’s d is shown for each pre- to post-float change score, with grey lines representing the 95% confidence interval. The dashed black line demarcates the starting point (d = 0.8) for what is considered a “large effect size” [73].