1. Introduction
Drug use poses a significant public health concern, with potential consequences including substance use disorders (SUD), mental health disorders, HIV infection, cancer, cirrhosis of the liver, hepatitis, overdose, premature death, and impaired cognitive function with chronic use [
1]. In general, addiction is a disorder of altered cognition and the brain regions that are affected by SUD overlap with those involved in cognitive functions such as learning, memory, attention, reasoning, and impulse control. Chronic drug use can alter brain structure and function, leading to addiction [
2], affecting memory and cognitive functions [
3]. Drugs have negative effects on natural cognitive function, promote drug use, and hinder the development of behaviors supporting abstinence. During substance abstinence, individuals may experience cognition-related withdrawal symptoms caused by many drugs that are usually temporary, in contrast with long-term use symptoms that lead to lasting cognitive declines. Moreover, cognitive deficits related to drugs may have negative effects on the individual's well-being [
4].
Individuals undergoing SUD treatment experience notable physical and cognitive benefits when incorporating exercise into their regimen. Research suggests that physical activity positively influences attention [
5], contributing to enhanced cognitive functioning and potentially supporting addiction recovery. Exercise programs and physical activities seem to be helpful in reducing cravings for substance use and promoting abstinence, and acting as valuable components for prevention and intervention, complementing traditional therapy. Some of the benefits of exercise are prevention of relapse, repair of cardiovascular and muscular damage, reduced symptoms of anxiety and depression and improved mood, increased self-confidence, self-esteem, and body image, improved well-being and quality of life, personal satisfaction, optimism and adopting a healthy lifestyle [6-8]. Systematic reviews documented the importance of physical activity and exercise programs in SUD treatment [
9,
10].
Attention is a large and complex topic involving psychology and neuroscience. Generally, attention could be described as the flexible control of limited computational resources [
11]. Many researchers have studied the influence of acute exercise on the Stroop effect (used widely to assess attention deficits) in healthy and clinical populations. The findings of a recent study, in which the Stroop test was applied pre, post, and 40 minutes post-resistance exercise, supported that acute exercise can lead to improved scores [
12]. The use of a virtual reality platform can also offer cognitive flexibility and selective attention improvements in young males, as exercise does offer such benefits [
13]. Therefore, a combination of VR and exercise may contribute to cognitive development. Furthermore, current investigations are delving into the potential advantages of high-intensity interval training for enhancing cognitive function in individuals with SUD [
14]. Additionally, a recent randomized controlled trial revealed significant enhancements in cognitive functions and emotional well-being among patients with SUD participating in a group-based aerobic exercise program [
15]. Notably, these findings underscore the promising role of exercise interventions in addressing cognitive deficits associated with SUD.
Self-efficacy is defined as the expectation that one can successfully perform a specific behavior required to produce a certain outcome [
16]. Positive self-efficacy is related to individuals' perceptions of their ability to control their own functioning and the events that affect their lives while decreased self-efficacy may lead to doubt and easily giving up in the face of obstacles [
17,
18]. Research by Schwarzer et al. 2014 [
19] indicates a strong connection between self-efficacy and both physical and mental health. There are, also, studies supporting that the consumption of illicit drugs is likely to impair individuals' self-control and self-efficacy [
20]. Other researchers support that there is a significant positive correlation between self-efficacy and treatment motivation [
21]. Increased levels of self-efficacy, and quality of life and social support were found to be negatively correlated with the relapse tendency in individuals with drug addiction [
22,
23]. The role of attitudes and intentions toward participation in sports and exercise programs has been documented. Positive attitudes and intentions toward substance abuse treatment are related to treatment completion. Attitude and control components are positively associated with intention and treatment participation or completion [
17,
18]. Furthermore, exercise can empower individuals under drug addiction therapy to achieve better fitness results and improve their psychological states, leading to positive changes in personality and psychological characteristics, including self-efficacy. Finally, exercise-induced improvements in self-efficacy can contribute to overall well-being and quality of life, promoting a positive mindset and sense of achievement throughout the recovery journey [
24].
Self-efficacy expectations, as outlined by Bandura (1977) [
16], pertain to an individual's belief in their capability to successfully execute behaviors required to produce specific outcomes in particular situations. This concept emphasizes the confidence an individual has in their ability to achieve desired results through their actions within specific contexts. The distinction between self-efficacy and self-efficacy expectations lies in their scope and focus. Self-efficacy encompasses a broader sense of overall competence and belief in one's abilities across various tasks and situations. In contrast, self-efficacy expectations are more specific, relating to an individual's confidence in their capacity to perform particular behaviors to achieve particular outcomes in defined circumstances [
16].
Exercise in a virtual reality (VR) environment has been a rising method of exercise in recent years. Several studies were involved with VR exercise and support that it is suitable to offer positive effects on physiological, psychological, and rehabilitation factors compared to conventional exercise [
25]. It has also been shown that exercise in a VR environment has positive effects on cognitive factors such as functional ability, attention, and memory and psychological factors such as depression and anxiety [
26]. VR exercise combined with cognitive tasks, according to another study, appeared to be appropriate and had positive effects even in people with mild cognitive impairment [
27]. Additionally, recent research by Krommidas et al. (2022) [
28] has highlighted the potential of acute exercise and virtual reality tasks to positively impact children's memory function and exercise preference, providing valuable insights into the broader applications of VR-based exercise interventions. VR environments are also a reliable way for providing information about addictive disorders, such as the desire to use, and can influence emotional state, attention, and cognitive function [
29]. At the same time, virtual environments can simulate reality without limitations in space and time, which makes them more attractive [
30]. Individuals with attention deficits, or those who face difficulties participating in group activities, may benefit from the virtual environment [
29].
To the best of our knowledge, there are few studies in the literature evaluating the effect of exercise in a virtual reality environment in populations in the treatment of SUD. According to what was mentioned above, it would be important to explore whether exercise in a VR environment could help to improve the self-efficacy expectations and attentional control of individuals in drug addiction treatment and be a useful and attractive tool to enhance their participation in an exercise program.
1.1. Research Questions and Hypotheses
In the present study, we sought to address several key research questions related to the utilization of IVR exercise as an intervention for individuals undergoing SUD treatment. Firstly, we investigated whether engaging in exercise with the IVR environment would lead to a significant improvement in self-efficacy expectations among participants in the SUD treatment program. We hypothesize that participation in IVR exercise would be associated with a noteworthy increase in self-efficacy expectations. Additionally, we explored potential differences in attentional control levels, as measured by the Stroop test, before and after a single session of cycling using the IVR system. We hypothesize that this intervention will decrease Stroop reaction time in people undergoing SUD treatment. Lastly, we delved into participants' attitudes, intentions for future use, and levels of interest/enjoyment regarding exercise within the IVR system. We hypothesize that individuals in the SUD treatment program would exhibit positive attitudes, express strong intentions for future use, and report high levels of interest/enjoyment concerning IVR-based exercise. Overall, these research questions and hypotheses were designed to comprehensively investigate the potential benefits of IVR exercise within the context of SUD treatment.
Therefore, the aim was to explore the acute effects of a pre- and post-exercise in an immersive virtual reality (IVR) environment on self-efficacy expectations and attentional control of individuals in SUD treatment. Additionally, their attitudes, intentions for future use, and interest/enjoyment about this type of exercise were investigated.
4. Discussion
In our feasibility study, we aimed to explore the self-efficacy expectations and attentional control differences of individuals in SUD treatment pre- and post-exercise in an immersive virtual reality (IVR) system and to investigate their attitudes, intentions for future use, and interest/enjoyment about this type of exercise, immediately after the exercise session. The findings of this study provide insights regarding the effects of an IVR exercise system on exercise self-efficacy expectations and performance in the Stroop test. Additionally, the results indicated positive outcomes and acceptance of the IVR exercise system for people under SUD therapy, thus suggesting the feasibility of this approach.
4.1. The Effects of IVR Exercise on Self-Efficacy Expectations of Individuals in SUD Treatment
In our study, we evaluated self-efficacy expectations before and after the IVR exercise. Consistent with Bandura's definition [
16], these expectations reflect an individual's confidence in their ability to accomplish tasks essential for desired outcomes in specific situations. Our findings revealed a significant improvement in self-efficacy expectations following the IVR experience. Panagiotounis et al.,2020 [
44] assessed self-efficacy in individuals in the treatment of substance use disorders. According to this study, the intervention lasted 5 days and was an adventure-based therapy for the promotion of participants' therapeutic change involving physical activity. The results have shown that the participants' self-efficacy and self-esteem were positively affected [
44]. Our findings did not unveil any significant relationship between self-efficacy and the repetition of motivational words; rather, this observation was discerned solely from the scatter plot. It is possible that the limited sample size may account for this outcome. According to our results, there were statistically significant differences in self-efficacy expectations, that can be positively influenced by one bout of exercise. This can be elucidated by emphasizing that, as previously noted, self-efficacy expectations are more precise, and engaging in exercise provides immediate successful experiences that strengthen individuals' confidence in their ability to participate in physical activity [
16]. From our perspective, IVR exercise shows promise as a tool for indirectly enhancing self-efficacy after a few times of exercising as we found improvements in self-efficacy expectations scores in acute exercise.
4.2. The Effects of IVR Exercise on the Attentional Control of Individuals in SUD Treatment
According to our results, there was a statistically significant reduction in reaction time in the Stroop test after the IVR exercise. It was observed that individuals with important positions with many demands and responsibilities for the community, such as drivers and coordinators noted better scores in all tabs of the Stroop test compared with members who were less active in their community. Nevertheless, covariate analysis didn’t find a significant effect. Our results are consistent with those of Smith et al.,2021 [
45] supporting that participants who engaged in a virtual reality exercise program as part of their treatment showed significant improvements in Stroop test performance after VR exercise [
45]. Based on our findings, it is plausible to suggest that IVR exercise may contribute to enhancing cognitive restoration during therapy. Likewise, previous studies have shown that individuals with substance use disorder exhibited reduced reaction time in the Stroop test following a single session of Tai Chi or high-intensity interval training, with the latter demonstrating superior improvement [
46]. The comparison of our Stroop test effect sizes with those of Zimmer et al., 2016 [
43] provides valuable insights into the potential impact of exercise intervention on cognitive function. Despite the acknowledged vulnerability of the Stroop test to practice effects, our study revealed significant differences in effect sizes, particularly in the naming and interference tabs, indicating a potential contribution from acute exercise. The higher Cohen's d values observed in these tabs compared to the control group of Zimmer et al., 2016 [
43] suggest temporary cognitive changes that extend beyond mere familiarity with the test. We also found significant relations between days in the treatment and the Stroop test pre-exercise score in the second tab of the Stroop test. There was a moderate negative relation between these variables and this can be a clue that maybe the days spent in abstinence from drugs may influence positively the cognitive function. Nevertheless, repeated measures ANOVA with covariate analysis on the relationship before and after IVR training Stroop test scores showed a non-significant effect of days in treatment. Research has consistently shown that longer durations of abstinence from drugs are associated with improved cognitive function, including attention, working memory, and executive control [
47,
48].
In our study, all participants were poly-users, but the vast majority of them reported that heroin was the substance that was the most difficult to abstain process. Heroin addiction has a negative effect on impulse control, attention, and flexibility. Moreover, the reaction time on heroin cues can be predicted by heroin craving levels [
49]. Due to the small sample size and the fact that all participants were poly-users, comparative analyses were not performed to examine the potential impact of the specific substances they used on their Stroop test scores.
4.3. The Attitudes, Intention for Future Use, and Interest/Enjoyment of Individuals in SUD Treatment toward IVR Exercise
According to the results, most participants showed increased levels of interest/enjoyment, intention for future use, and positive attitudes toward the IVR exercise system indicating positive perceptions and high motivation. Interest/enjoyment is a dimension of intrinsic motivation and the high scores indicate positive motivation. These results suggest that the participants after using the IVR exercise system, had a favorable attitude toward the IVR exercise system, intended to use it in the future, and expressed strong interest and enjoyment during the VR cycling experience. These results align with participants' feedback regarding their virtual experience from the interview. Notably, there were no reports of adverse effects such as nausea or dizziness, and overall comments on the VR exercise application were highly positive. However, several participants mentioned that they found the landscape to be somewhat monotonous. While this feedback is valuable, it should be considered for future studies utilizing the VRADA application. Furthermore, the feedback gathered from questions presented on the screen following the cycling performance was overwhelmingly positive. The majority of participants expressed satisfaction with their exercise experience and reported no feelings of fatigue. However, there were fewer positive responses regarding the word repetition task, indicating that some participants found this aspect less enjoyable or engaging.
In our study, participants chose their preferred landscape (forest, beach, snowy landscape) and cycling duration (5 to 30 minutes) in the virtual reality environment, receiving real-time feedback on speed, distance, and remaining time, while also having the option to select music from a list of songs. Research consistently demonstrates that incorporating choices into individuals' exercise routines significantly enhances their experience and motivation. By allowing participants to select key elements such as exercise duration, preferred music, and the surrounding landscape, exercise programs become powerful tools for providing autonomy. This practice aligns with motivational techniques rooted in self-determination theory, fostering intrinsic motivation and a greater sense of ownership over one's fitness journey [
50]. The ability to tailor exercise programs to individual preferences not only makes them more personalized but also increases engagement and enjoyment. Ultimately, these autonomy-supportive strategies contribute to a positive and individualized exercise experience, promoting sustained adherence and overall well-being.
Virtual reality exercise has emerged as a promising tool for individuals in substance use disorder treatment, as it offers a unique and immersive approach to physical activity. Studies assessing the effects of virtual reality exercise on individuals in substance use disorder treatment have found positive outcomes in terms of interest/enjoyment, attitudes towards exercise, self-efficacy, and cognitive function measured through the Stroop test. For instance, a study by Nesbitt et al.,2020 [
51] investigated the use of virtual reality exercise among individuals in substance use disorder treatment and found that participants reported high levels of interest and enjoyment during virtual reality exercise sessions [
50]. Another study demonstrated that virtual reality exercise interventions were associated with improved attitudes towards exercise and increased self-efficacy among individuals in substance use disorder treatment [
52]. Furthermore, other researchers examined the effects of virtual reality exercise on cognitive function using the Stroop test in individuals with substance use disorder and found significant improvements in attention and inhibitory control following virtual reality exercise sessions [
53].
4.4. Strengths & Limitations
This study contributes significantly to the emerging field of IVR exercise interventions for individuals undergoing substance use disorder (SUD) treatment. One of its primary strengths lies in its holistic approach, exploring not only the cognitive benefits but also participants' attitudes, intentions, and interest/enjoyment related to IVR exercise. The utilization of both quantitative measures, such as the Stroop test for attentional control, and qualitative data provides a comprehensive understanding of the intervention's impact.
Despite its strengths, this study has several limitations that warrant consideration. The relatively small sample size may limit the generalizability of the findings to a broader population. The study's focused exploration within a specific population undergoing substance use disorder treatment, coupled with resource constraints for intensive assessments, necessitated a smaller sample size of 20 participants. While limited in generalizability, this approach allowed for in-depth insights and laid the groundwork for future, more extensive investigations. The absence of a control group and random assignment is acknowledged, posing challenges in establishing causal relationships. The quasi-experimental design, while providing initial insights, necessitates caution in generalizing findings to long-term effects, highlighting the need for future studies with extended interventions and control conditions. According to Edwards et al., 1996 [
54], it is possible that the practice effect from the Stroop test may have influenced the positive results regarding attention. Therefore, because our study design did not include a control group, we might have had the effect of practice when we compared the before–after Stroop test scores. Nevertheless, previous studies examining the effect of exercise on Stroop performance, indicated that an acute bout of exercise led to improved scores in the Stroop test, compared with a control group [
55]. According to our findings the effect size of the Stroop task in our study was higher compared to the control group of Zimmer et al., 2016 [
43]. These findings underscore the nuanced effects of exercise on cognitive performance and highlight the need for further research to elucidate the mechanisms underlying these effects. Additionally, in this study, we observed that individuals with important positions and numerous demands and responsibilities in the community, such as drivers and coordinators, achieved better scores in all tabs of the Stroop test compared to members who were less active in their community. This observation underscores the importance of considering such factors in future studies on this topic. In conclusion, there is a need for further research involving extended exercise interventions utilizing VR environments, larger sample sizes, randomized controlled trials, and prolonged follow-up periods. These endeavors will serve to validate and expand upon the current findings, shedding light on whether such exercise modalities could contribute to reduce drug use, and cravings or enhanced recovery self-efficacy.
Author Contributions
Conceptualization, E.T, M.H., F.P. and Y.T.; methodology E.T, M.H., F.P. and Y.T.; validation, M.H and Y.T.; formal analysis, E.T and V.S.; investigation, E.T.; data curation, E.T. and E.G; writing—original draft preparation, E.T..; writing—review and editing, M.H., V.S., F.P., E.G., M.G., Y.T..; resources, F.P., Y.T, visualization, M.H.; supervision, Y.T. All authors have read and agreed to the published version of the manuscript.”.