This randomized, controlled, single-blinded trial was conducted in 2023 with a 3-arm design at a single center conducted in 2023. Participants were recruited from a recovery center in Tehran, IRAN. The flow chart of the trial is visualized in Fig 1.
2-1- Participants
The study focused on patients with substance dependency and undergoing detoxification at a rehabilitation facility for a duration of 10 to 14 days. All participants were men between the ages of 20 and 60, undergoing detoxification, and without a history of psychotic or neurological disorders, epilepsy, or seizures. Patients were excluded if they did not complete questionnaires or sessions or experienced unusual symptoms like headaches. The sample size for this study was determined using GPower v3.1.1, with an effect size of 0.40, power of 0.8, and 3 groups. The calculated minimum sample size was 52 patients; ultimately, 60 patients (20 patients in each group) were included in the study.
2-2- Procedure
All patients in the center were given a unique number based on their name and then randomly assigned to one of three groups using a number generator app. The researcher explained the study procedure to each patient, but they were not informed about the different scenarios in each group. Prior to the study, written consent was obtained from all participants. A trained clinical psychologist conducted all procedures in a quiet room.
Initially, the participants completed self-reported questionnaires, which included the perceived stress scale (PSS) and positive and negative affect scale (PANAS). Subsequently, participants in the experimental group were asked to wear a Meta Quest 2 VR (Meta Technology, LLC) headset and watch 360-degree videos for 12 minutes while seated in a chair in a room devoid of any external visual or auditory distractions. The headset featured a 5.5" fast-switching LCD at an 1832 x 1932 pixel per eye resolution. Group one, also known as the nature group, watched 12-minute 360-degree high-definition nature scenes. These nature scenes featured expansive views of water, jungle, and beach, but did not include any animals or human elements. Sounds of nature and soothing music accompanied the scenes. Group two, the control group, did not receive VR. They sat in the same room as the other groups and had their physiological data recorded, like the nature and city groups. Group three, the city group, watched 12-minute 360-degree high-definition scenes of cities. These scenes included large and expansive views of outdoor and indoor cityscapes with city sounds. Throughout the VR experience, respiratory rate, skin conductance, and heart rate were measured, and scales were filled out again after the VR experiences.
2-3- Tools
The study recorded demographic information of the participants, such as their age, education level, and marital status.
Psychophysiological measures
During the experiment, a Procomp-5 Infiniti system (Thought Technology Ltd. Quebec, Canada) was used to obtain heart rate, skin conductance, and respiration data. An SC Flex/Pro sensor was used to measure skin conductance. It works by applying a tiny electrical voltage through two electrodes strapped to two fingers of one hand, creating an electric circuit where the subject becomes a variable resistor. As the subject becomes more stressed, the skin's conductance increases proportionally, and vice versa (Choudhary et al., 2016). The heart rate was measured with a BVP sensor, where a higher heart rate indicates higher stress levels (Choudhary et al., 2016). In order to measure abnormal respiration rates, a Resp-Flex/Pro sensor was employed. When a person is highly aroused, their respiration rate increases; conversely, when they are relaxed, it decreases (Omata & Tanabe, 2015).
2-4- psychological measures
PSS measures one's perception of life as unpredictable, unmanageable, and troublesome. The scale consists of 10 items, each evaluated on a Likert scale ranging from 0 (never) to 4 (often). A higher score on the scale indicates a greater level of perceived stress (Mazgelytė et al., 2021). The Persian version of this questionnaire has a reliability of 0.90 and a validity of 0.69 (Maroufizadeh et al., 2014). PANAS, on the other hand, is used to evaluate one's immediate affect. It consists of 20 questions, with half of the provided emotion words associated with positive affect (such as interested, alert, attentive, excited, enthusiastic, inspired, proud, determined, strong, and active) and the other half with negative affect (including distressed, upset, guilty, ashamed, hostile, irritable, nervous, jittery, scared, and afraid). Each question is answered on a 5-point Likert scale ranging from "very slightly" to "very much." The score for each emotion is calculated and combined to generate separate measures for positive affect (PA) and negative affect (NA), which are independent of each other (Anderson et al., 2017). The Persian version of this questionnaire has a reliability of 0.87 and a validity of 0.77 (Ghorbanshiroudi & Abbas Ghorbani, 2012; SHARIFI et al., 2012).
2-5- Statistical analysis
The data are presented as mean with standard deviation (SD), and categorical data are reported as numbers with percentages. The normality of the data was assessed using the Shapiro-Wilk test. Demographic data were compared using One-way ANOVA or the Kruskal-Wallis H test. The paired t-test was used to compare approximately normally distributed continuous variables, while the repeated measure ANOVA was used to analyze continuous data. A P-value of less than 0.05, two-sided, was considered significant. The statistical analysis was conducted using R version 4.2.1 (R Foundation for Statistical Computing Vienna Austria).