This early-stage pilot trial aims to examine the feasibility, tolerability, and safety of Floatation-REST, or Reduced Environmental Stimulation Therapy via floatation in frontline healthcare workers, first responders, and emergency medical personnel who experience post-traumatic stress symptoms.

Frontline healthcare workers, first responders, and emergency medical personnel are repeatedly exposed to occupational stressors and potentially traumatic events, placing them at elevated risk for post-traumatic stress symptoms (PTSS), burnout, anxiety, and related impairments. Current stress-reduction approaches for healthcare workers often have limited evidence for efficacy or may be difficult to implement in high-demand emergency and healthcare settings. Therefore, rapid, low-burden interventions that are feasible, tolerable, and safe for this population are needed.

Floatation-REST, or Reduced Environmental Stimulation Therapy, is a non-pharmacological intervention that reduces sensory input to the nervous system through the act of floating supine in a pool of warm water saturated with Epsom salt. The float environment is designed to reduce visual, auditory, thermal, tactile, vestibular, and proprioceptive stimulation. Prior studies suggest that Floatation-REST may acutely reduce stress and anxiety-related symptoms, but it has not yet been systematically evaluated in frontline healthcare workers with elevated PTSS.

This single-site, double-arm pilot study will examine the feasibility, tolerability, and safety of two 60-minute sessions of Floatation-REST compared with a documentary-viewing condition in adults ages 18 to 64 with work-related post-traumatic stress symptoms. Up to 30 participants will be recruited, with the goal of retaining 15 completers randomized on a 2:1 basis to Floatation-REST versus comparator condition. Participants will complete two in-person study visits at the Laureate Institute for Brain Research, including self-report questionnaires, blood and saliva collection, functional magnetic resonance imaging scans, and either Floatation-REST or documentary viewing. Follow-up surveys will be completed virtually up to one week after final intervention session.

The primary aim is to evaluate the safety and tolerability of Floatation-REST in this population. Secondary aims will explore whether Floatation-REST is associated with acute changes in PTSS, perceived stress, anxiety, burnout, mood, mindfulness, and moral injury-related distress. Exploratory aims will examine whether changes in brain network connectivity, salivary cortisol, and blood-based proteomic markers may help explain symptom change. Results from this early-stage study will help determine whether Floatation-REST should be further studied as a potential intervention for post-traumatic stress symptoms in frontline healthcare and emergency personnel.

Inclusion Criteria:

1. Work-related post-traumatic stress dysfunction as measured by either of the following inclusion pathways:

   (A) PTSS Pathway: PCL-5 greater than or equal to 20, OR meets criteria for full or partial PTSD on the MINI International Neuropsychiatric Interview 7 (DSM-V) (Criteria A + at least 2 B-E Criteria) OR (B) Functionally Anchored Pathway: evidence of work-related trauma exposure on the MINI International Neuropsychiatric Interview 7 (DSM-V) (Criterion A) or Life Events Checklist-5, and at least one of the following: Moral Injury and Distress Scale greater than or equal to 27, Sheehan Disability Scale greater than or equal to 5 on at least 1 of the 3 subscales, high or very high level of perceived stress (measured by PhenX Perceived Stress Scale greater than or equal to 16).

2. First responder or other emergency medical personnel

3. Ability to read, speak and understand English

4. Capable of providing consent

Exclusion Criteria:

1. History of neurological conditions
2. Skin conditions or open wounds
3. DSM-5 diagnosis of psychotic spectrum disorders, obsessive-compulsive disorder, bipolar disorder, severe substance use disorder, or eating disorder
4. Inability to lay comfortably in a shallow pool of water
5. Failure to adhere to "pre-float checklist"
6. Breathalyzer test positive for alcohol or a drug-positive urine test
7. Unwillingness to provide consent or complete major aspects of protocol
8. MRI contraindications
9. Unstable medical diagnoses
10. Pregnancy
11. Evidence of inability to comply with study procedures based on experimenter judgement
12. Change in the dose or prescription of a medication within the 6 weeks before enrolling in the study that could affect brain functioning (e.g., anxiolytics, antipsychotics, antidepressants, benzodiazepines, or mood stabilizers)