The advent of the term VR dated back to the 1960s [1] when the mechanical device Sensorama Simulator was first introduced [2]. Macpherson and Keppell [3] defined VR as “a state produced in a person’s mind that can, to varying degrees, occupy the person’s awareness in a way similar to that of real environments”. The key features of VR include a three-dimensional imaging which can either be a real-world object or an abstract world, the ability of active interaction with the virtual environment, and a visual and auditory feedback [4]. VR environments can be further classified as immersive and non-immersive. Immersive VR involves frequent interactivity and a peripheral device such as head-mounted displays (HMDs) or a room where the walls are projection screens (CAVE) while non-immersive VR involves computer monitor and little interaction with the mouse [5].

With advancement in VR hardware, the current display technology can provide users visual displays with haptic and multi-sensory feedback via output devices like HMDs [6]. The mobile HMDs including the Google Cardboard and Gear VR were developed to provide simple casing for users to carry their smartphones as displays and data processors [6]. By utilizing the computer-generated 3D real-time environments with the output devices, users can experience in three aspects from the physical world, which are actual geographic distance elimination, genetically generated physical distances elimination, and temporally coordinate ability [7]. After the invention of a new generation of HMDs from Oculus Rift [8], VR simulation became more accessible for research and education purposes. Consequently, the New Media Consortium Horizon report in 2016 had predicted that the VR technology will be adopted in higher education field in two to three years [9].

An integrative review has revealed the paucity of adequate mental health educational preparation among general health professionals who are required to deliver different level of care to patients of mental illness in various healthcare settings [10]. Studies revealed that general healthcare professionals had significant shortcomings in knowledge and attitude pertaining to psychiatric disorders, which hinder the provision of adequate and appropriate services [10] [11]. While the ubiquitous stigmatizing attitude among health professionals was attributed to their experience [12], experiential mental health training with supervised clinical experience were found to facilitate the effectiveness of the programs [10]. The effectiveness can be explained by Kolb’s Experiential Learning Theory of which, in the cycle of diverging, assimilating, converging, and accommodating [13], learners can react to their individual perceptions of experiences under the philosophical principle of constructionism [14]. Studies in psychology have shown an increase in the application of Experiential Learning Theory in psychometrics [13].

Simulation-based activities entail the creation of a “real” situation which immerses learners in an experience while developing new skills, new attitudes, or new ways of thinking in a safe environment [15]. It engages students in an experiential learning process with the goal of achieving cognitive, psychomotor and affective domain of learning [15]. It has expanded exponentially in healthcare education recently to diversify the range of clinical and nonclinical skills, including physician clinical skills, midwifery skills, laparoscopic surgery training or understanding of mental illness [16] - [22]. The most common simulation methods adopted in undergraduate curriculum of mental health training are the use of standardized or simulated patients and voice-hearing simulations, so as to enhance students’ therapeutic communication technique and reduce fear [23]. Although healthcare simulation is identified as a powerful tool a change in practice among student in the health profession [24], the conventionally adopted simulation were critiqued for lacking realism and attention to organizational contexts [25] [26]. The proliferation of VR tools has increased usage in the field of education over the last decades owing to its greater ecologically valid stimulus presentation and tighter control of 3D simulated environment [27]. With the highly manipulative virtual environments, VR technology is suggested to have high flexibility in providing systematic experiential training that optimizes the degree of transfer of training to individual’s reality perceptions [28]. VR simulations may, therefore, provide a more realistic experiential learning environment in the highly flexible and programmable virtual environment to healthcare learners than the conventional simulation [28]. Pantelidis [29] suggested that VR simulation of teaching scenarios can be adopted when “information visualization is needed, manipulating and rearranging information, using graphic symbols, so it can be more easily understood”. While visualization of hallucinations has been effective in reducing stigma of schizophrenia [30], VR simulation has the advantage of transforming not only hallucination, but also other psychotic symptoms and patient’s experience into high level of personal efficacy and self-reflectiveness, and engaging multiple senses which is suitable for mental health education [31] [32]. Nonetheless, on the grounds that studies have shown medical students and health professionals having a higher level of perceived stigmatization and lacking knowledge related to mental illness, VR simulation may emerge as a novel education approach in mental health training. This research gap has provoked the sine qua non on further review on the impact of VR simulation on mental health education.

The timeframe chosen was from January 1, 2007 to December 31, 2018, as the analysis aimed at reviewing the effectiveness of virtual reality-based simulation in mental health education. Searches were performed in PsycINFO, CINAHL, Education Resources Information Center (ERIC) and Pudmed on January 4, 2019 which included the terms “Medical Education”, “Clinical Education”, “Health Education” and “Mental Health Education”, and “Virtual Reality Simulation”, “Virtual Reality” and “Mental Disorders”, “Mental Illness”, Mental Illnesses” and in the title or abstract with the language restriction of English. In addition to the electronic databases, references list of all selected articles were manually searched to identify further relevant articles and earlier seminal sources.

To be eligible for inclusion for full text final review, studies had to: 1) Targeted experimental studies to evaluate the effect of virtual reality simulation in mental health education; 2) Quantitative or qualitative data for the result analysis; and 3) Published in English. Publications with no title or abstract, and book chapter, and reviews, and editorials will be excluded. Studies that did not include virtual reality simulation training and mental illness related training in the result analysis were excluded.

The inclusion criteria for participants in this review were all students at varying levels of enrollment studying health-related subjects/programs, or health care professionals. Besides, participants with no fulfillment of inclusion criteria will also be included as compassion group in this review to examine the difference in feasibility and effectiveness between those of health care backgrounds and non-healthcare backgrounds.

Interventions of analysis were the interventions adopting VR simulation mental health education training as the primary component to examine the effectiveness of VR simulation to the health professionals.

The outcomes include students’ empathy, attitudes and knowledge. The most frequently endorsed fundamental techniques in practice for psychotherapists were relationship-oriented for instance empathy, understanding and attitudes towards psychiatric clients [33]. To measure the effectiveness of the VR simulation education relating the mental illness, the current review explored the opportunity of VR simulation used as an educational tool to enhance students’ empathy and attitude towards mental illness patients, and academic-based learning on the symptoms or the technical skills on patients caring.

The following data were extracted from each article to standardize the reviewing process. The defined extractions were: Study and participant characteristics (e.g. study design, study purpose, sample size and recruitment method); primary results of the measurements on subjects’ knowledge, attitudes or empathy; limitations; and the conclusion of the authors drew on the effectiveness of virtual reality-based simulation in healthcare education to enhance students’ knowledge, attitudes, and empathy relating to mental illness.

After the removal of duplicate articles from 1038 articles that were searched via PsychINFO, CINAHL, ERIC and PubMed, 1034 articles were identified eligible in the databases that were published since January 2007. After the title and abstract selection in accordance to the exclusion criteria, 758 articles which obviously meet the exclusion criteria were excluded and 31 full-text publications were retrieved and reviewed for final selection. Of these, 25 articles were excluded according to the exclusion criteria with 6 articles which are four single-case research studies and two quasi-experimental studies meeting the inclusion criteria (Figure 1).

Sample sizes of participants ranged from 80 to 800 while the subject groups of the articles are two for nursing students [34] [35], one for medical and other health professions students [36], one for informal caregivers [37], one for teachers [38], and one for general public and psychology undergraduate [39].

Among the 6 selected articles to answer the research question, most of the articles [34] [35] [36] [38] [39] (n = 5) confirmed the association between users’ exposure to VR simulation and users’ improvement in knowledge, attitudes, or empathy. Only one article [37] has concluded that no significant differences were found between exposure to VR simulation and users’ empathy and sense of competence (Table 1).

The literature identified that the majority of the research focused on the impacts of VR simulation on users’ knowledge and empathy relating to mental illness while users’ attitude has been examined in two studies only. Findings are presented below with brief discussion and analysis.

Preston [40] suggested that empathy is defined by most current researchers as a subject having “a similar emotional state to an object as a result of the accurate perception of the object’s situation or predicament”. Meanwhile, enhancing empathy is the increase of ability in relating the feelings perceived from others with our own experience and inferring what others are going through [41].

Of the three studies [36] [37] [39] that examined users’ empathy, two of them [36] [39] have confirmed the association between VR simulation and heightened empathy while the remaining [37] found no significant differences. Meanwhile, only the study from Dyer et al. examined the impacts of VR simulation on health profession students.

The study conducted by Dyer and colleagues [36] examines the empathy gain of medical students towards Alzheimer’s disease patients with cognitive and physical degeneration experience via VR simulation, in which 800 showed increased empathy for the Alzheimer’s disease. Subjective reports from participants indicated that VR simulation could be an effective training tool for mental health professionals in empathy gain due to its capability of simulating high levels of emotional experience of the “stigmatized other” with immersive environment. This is consistent with the study conducted by Formosa and colleagues [39], which recruited fifty participants with a psychology undergraduate degree (n = 3) and individuals from the general public (n = 47) and utilized a custom-made VR simulation which provided users the immersive story-driven replication of positive schizophrenic and other psychotic disorder symptoms such as auditory and visual hallucinations, and paranoid delusional thoughts. Findings from the participants’ pre and post-test scores exhibited significant enhancement of empathetic understanding towards patients with schizophrenia and other psychotics (p < 0.001). The features of high fidelity and users’ buy-in of VR simulation had found to be associated with the empathy gain scores.

Contrary to the findings of a positive relationship between VR simulation and empathy gain in the aforementioned studies, Jütten and colleagues [37] found no significant differences (p = 0.862) between the two. The study recruited 201 informal caregivers for people with dementia and 145 participants who were assigned to the intervention group to the experience of dementia-like symptoms in a VR simulation. They suggested that a lack of educational features such as including role playing and accompanying feedback of VR simulation could have contributed to the negative result.

Stigmatized attitudes and beliefs towards mental illness can be in the form of social stigma [42]. While health professional is a member of the general public, stigma towards clients can be found in various studies [43] [44] [45]. Cashwell [46] suggested that mental health related training professionals can have less stigmatizing attitudes than non-mental-health professionals. Changing negative attitude and stigma of either general public or medical professionals towards mental illness is vital as stigma significantly hindered the recovery of mental illness [47].

Two studies [37] [39] have discussed the VR simulation impact on users’ attitude and both have shown a positive relationship between VR simulation and improvement on understanding and stigmatization. Both of them conducted the study on a non-healthcare population.

Jütten and colleagues [37] found that the dementia patient’s informal caregivers who underwent their VR simulation have heightened their understanding of the disease which was beneficial for both the caregivers and patients. Almost all caregivers in the study indicated that they changed the way they cared for the dementia patients and became more effective caregivers after the VR simulation. Jütten and colleagues suggested that a better understanding can lead to a better relationship with and enhanced well-being of the patients with fewer communication problems. Consistent with the study conducted by Formosa and colleagues [39], participants’ scores on the area of fear and exclusion, understanding and tolerance, and community integration were significantly increased in the attitude posttest (p < 0.001).

Taken social desirability response bias into account, Jütten and colleagues [37] argued that the positive attitude of the caregivers was valued over the change on empathy.

The users’ knowledge gain was seen having the greatest research interests among researchers studying the impacts of VR simulation on medical education of mental illness as all of the selected articles have measured users’ knowledge as part of their research outcome. As the Canadian Alliance on Mental Illness and Mental Health emphasizes the importance of mental health literacy in the recognition [48], management or prevention of mental health problems, enhancing users’ knowledge on mental illness has a potential benefit on medical education.

There are five selected articles which examined users’ knowledge and all of the articles [34] [35] [36] [38] [39] have the unanimous conclusion on the relationship between VR simulation and the improvement in awareness of disease, symptom identification and skill competence. Three of them assessed VR simulation as a teaching strategy in health profession students [34] [35] [36].

Sweigart and colleagues [34] have found significant improvement among student nurses using a psychiatric assessment tool (p = 0.001) after they experienced virtual dialogs with patient avatars in the virtual clinic constructed in the world of Second Life. Students with no virtual interview experience had a lower average score on questions assessed during an interview compared to those who had interviewed a patient avatar in a virtual environment. The data supported the efficacy of VR simulation on the transference of skills to practice on students. It is in line with Kidd and colleagues’ [35] study that adopted VR simulation in mental status assessment and communication with patients among undergraduate mental health nursing students. The 126 mental nursing students indicated the benefits of VR simulation as allowing students to learn communication and health assessment skills in a stress-free environment where mistakes would not lead to catastrophic outcomes. Dyer [36] also found health profession students demonstrating an increased understanding for older adults who have Alzheimer’s disease.

Passig and colleagues [38] attributed the effectiveness of VR simulation on enhancing users’ knowledge to its capability in transforming an experience hard to illustrate verbally into a virtual visible scenario. Formosa and colleagues [39] also suggested similar findings in their study that while there is no overt ways of teaching diagnostic technique of schizophrenic symptoms via VR simulation, learners can still benefit from content-based knowledge.