1. Complete one chapter of the virtual reality game "Land's End" while simultaneously using the tACS system (chapters range in length from approximately 5-20 minutes) after waking up each day (or prior to beginning a work shift).
2. Use the tACS system without the VR for 20 minutes just before sleep (or at the end of a work shift, whichever time point is most convenient). Table 1. Timeline of Study Treatment

For 2 weeks of the 4 week study, each group (Group A and Group B) will continue work shifts as usual with no intervention.

TACS- A regulated class of transcranial alternating current stimulation (tACS), called Cranial Electrotherapy Stimulation (CES) by Fisher Wallace Laboratories (FWL) is FDA-Cleared to treat depression, anxiety, and insomnia (Proof of FDA clearance and 510k provided in the appendix). FWL tACS delivers weak non-invasive electrical stimulation (1-4 milliamps at 15, 500, and 15,000 Hz) to the frontal/temporal brain regions by electrodes placed above the temples. Land's End Virtual Reality Game Meta-analyses show Virtual Reality (VR) is an effective non-pharmacological method that reduces obstacles to human performance such as pain, insomnia, anxiety, sleep deprivation, and a variety of other stress responses.

The Numerical Rating Scale (NRS) has been validated as a measure of pain intensity and is one of the most commonly used measures in assessing pain. The NRS asks patients to rate their pain severity on a 0 to 10 scale, with 0 being "no pain" to 10 being "so severe that you can't stand it."

The Insomnia Severity Index (ISI) is a 7-item, self-report instrument that assesses the severity of insomnia. The ISI has adequate reliability and validity and is frequently used in randomized controlled trials of sleep interventions. A 5-point Likert scale is used to rate each item (e.g., 0 = no problem; 4 = very severe problem), yielding a total score ranging from 0 to 28. The total score is interpreted as follows: absence of insomnia (0-7); sub-threshold insomnia (8-14); moderate insomnia (15-21); and severe insomnia (22-28).

The PHQ-8 is a brief self-report measure of major depressive disorder. The PHQ-8 is considered to be valid measure of depression for population-based studies and clinical populations with a cut off score of equal or greater than 10 as the diagnostic for current depression. The PHQ-8 is derived from the PHQ-9 by removing the last question regarding suicide assessment.

The PC-PTSD is a 4-item"yes" or "no" screen designed for use in medical settings and is the current screening instrument used in the VA system to screen for PTSD. This is considered a psychometrically sound screen for determining the presence and absence of PTSD in the VA setting and has also been used in the civilian primary care population. With a cut-off score of 3, the PC-PTSD has shown 85% diagnostic efficiency, 78% sensitivity, and 87% specificity.

Participants will be asked to provide standard demographic information (i.e., age, gender, race/ethnicity, level of education, etc.). Participants will also be asked about hearing and visual impairment as well as any history of motion sickness.