Information extraction

Information extraction was carried out by the first author and independently rated by the third author. The literature search identified 638 articles, from which 369 potential studies were identified for screening. Of these, 50 were included in the review (see Fig. 1). While all studies assessed the safety and acceptability of the VR environment, three studies focussed specifically on the safety and acceptability of VR with a psychosis population. Eleven studies focussed on neurocognitive evaluation; nine on the assessment of functional capacity, social cognition and social competence; 19 on the assessment of psychosis symptoms; and eight on the use of VR in the treatment of psychosis.

Fig. 1. PRISMA flow diagram.

Quality assessment

Independent ratings were carried out by the first and last authors, resolving disagreements by consensus. As shown in Tables 1–5, the majority of studies received a QATA global rating of strong. It is however important to point out that the QATA defines a paper with no weak ratings as ‘strong’, even if the individual score on several subscales is moderate. Despite achieving an overall rating as ‘strong’, several papers had a score of moderate on one of more subscales reflecting small sample sizes and some methodological issues discussed below.

Table 1. Studies assessing safety and acceptability of VR in people with psychosis

HMD, head-mounted display; s.d., standard deviation; SSQ, Simulator Sickness Questionnaire; STAI, Spielberg State-Trait Inventory; VAS, Visual Analogical Scale; VR, virtual reality.

Table 2. VR studies of neurocognitive evaluation in people with psychosis

BADS, Behavioural Assessment of the Dysexecutive Syndrome; BPRS, Brief Psychiatric Rating Scale; CGI, Clinical Global Impressions; FSIQ, Full Scale Intelligence Quotient; GAF, Global Assessment of Functioning; HMD, head-mounted display; K-MMSE, Korean Mini-Mental State Examination; MATRICS, Measurement and Treatment Research to Improve Cognition in Schizophrenia; MRT-A, Mental Rotation Test-A; PANSS, Positive and Negative Symptoms Scale; RBANS, Repeatable Battery for the Assessment of Neuropsychological Status; SANS-SAPS, Scale for the Assessment of Negative and Positive Symptoms; SCID, Standard Clinical Interview for DSM Disorders; s.d., standard deviation; SPM, Standard Progressive Matrices; VR, virtual reality; WAIS-R, Wechsler Adult Intelligence Scale; WCST, Wisconsin Card Sorting Test; WMS-R, Wechsler Memory Scale Reviewed; WRAT-4, Wide Range Achievement Test-4.

Table 3. VR studies of functional capacity and social cognition and social competence

BADS, Behavioural Assessment of the Dysexecutive Syndrome; CPT, Continuous Performance Test; HMD, head-mounted display; HVLT, Hopkins Verbal Learning Test; IIT, Intention Inference Test; ITQ, Immersive Tendency Questionnaire; MATRICS, Measurement and Treatment Research to Improve Cognition in Schizophrenia; MMA, Medication Management Assessment; NART-R, National Adult Reading Test Revised; PANAS, Positive Affect and Negative Affect Scale; PANSS, Positive and Negative Symptoms Scale; PQ, Presence Questionnaire; RPM, Raven's Progressive Matrices; SCID, Standard Clinical Interview for DSM Disorders; s.d., standard deviation; STAI, State-Trait Anxiety Inventory; TAS-20, Toronto Alexithymia Scale; UPSA-B, Performance-Based Skills Assessment; VR, virtual reality; VRAMMA, Virtual Reality Apartment Medication Management Assessment; VRQ, Virtual Reality Questionnaire; WMS-R, Wechsler Memory Scale Reviewed; WWM, Wechsler Working Memory Test.

Table 4. VR assessment of paranoid ideation and auditory hallucinations

ASSQ: Autism Spectrum Screening Questionnaire; ATQ, Automatic Thoughts Questionnaire; CAPE, Community Assessment of Psychic Experience; CAPS, Cardiff Anomalous Perceptions Scale; CAS, Cognitive Assessment Schedule; DASS, Depression, Anxiety, Stress Scale; ERQ, Emotion Regulation Questionnaire; GPTS, Green Paranoia Thoughts Scale; HADS, Hospital Anxiety and Depression Scale; HMD, head-mounted display; IPSM, Interpersonal Sensitivity Scale; LSAS, Liebowitz Social Anxiety Scale; LSHS, Launay-Slade Hallucinations Scale; PANSS, Positive and Negative Symptoms Scale; PEDQ-CV, Perceived Ethnic Discrimination Questionnaire community version; PQ, Presence Questionnaire; PSWQ, Penn State Worry Questionnaire; PSYRATS, Psychotic Symptoms Rating Scale; RBQ, Retrospective Bullying Questionnaire; RSES, Rosenberg Self-Esteem Scale; SADS, Social Avoidance and Distress scale; SCS, Social Comparison Scale; s.d., standard deviation; SDCS, Social Defeat Composite Scale; SIAS, Social Interaction Anxiety Scale; SSPS, Social State and Paranoia Scale; SSQ, Simulator Sickness Questionnaire; STAI, State-Trait Anxiety Inventory; TVRS, Topography of Voices Rating Scale; UHR, ultra high risk; VAS-VR Paranoid, Visual Analogical Scale to assess paranoia in virtual reality environment; VR, virtual reality.

Table 5. VR for the treatment of psychosis

BCSS, Brief Core Schema Scale; BNCE, Brief Neuropsychological Cognitive Examination; COGNISTAT, Neurobehavioural Cognitive Status Examination; DVT, Digit Vigilance Test; HMD, head-mounted display; PANSS, Positive and Negative Symptoms Scale; POD, Paranoid, Obsessive-Compulsive and Depression Scale; PSYRATS-AH, Psychotic Symptom Rating Scale Auditory Hallucinations Section; RAS, Rathus Assertiveness Schedule; RBMT, Rivermead Behavioural Memory Test; RCS, Relationship Change Scale; SADS, Social Avoidance and Distress Scale; s.d., standard deviation; SFS, Social Functioning Scale; SIAS, Social Interaction Anxiety Scale; SPSI-R, Social Problem Solving Inventory-Revised; SSIT, Simulated Social Interaction Test; SSQ, Speech, Spatial, and Qualities of hearing Scale; VCRS, Vocational Cognitive Rating Scale; VQ, Vocational Questionnaire; VR, virtual reality; WCST, Wisconsin Card Sorting Test.

Safety and acceptability

Demonstrating the safety and acceptability of using VR with people experiencing psychosis has been an essential area of research in establishing the feasibility of using VR in this context. All studies reviewed in this manuscript addressed this important issue in their design, but three studies specifically reported results about safety and acceptability of this technology. Qualitative assessment showed that the patients’ attitude towards using a virtual environment was positive, and they reported completing tasks by using computers to be engaging (da Costa & de Carvalho, Reference da Costa and de Carvalho2004). Participants at ultra high risk for psychosis, healthy controls (Valmaggia et al. Reference Valmaggia, Freeman, Green, Garety, Swapp, Antley, Prescott, Fowler, Kuipers, Bebbington, Slater, Broome and Mcguire2007) and individuals with persecutory delusions (Fornells-Ambrojo et al. Reference Fornells-Ambrojo, Barker, Swapp, Slater, Antley and Freeman2008) did not report raised levels of anxiety or simulator sickness either during the VR exposure or in the week following the experiment.

Neurocognitive evaluation

Neurocognitive evaluation can be described as a method through which data about a participant's cognitive, motor, behavioural, linguistic and executive functioning are acquired. The majority of the studies reviewed investigated the use of VR in the assessment of memory (Ku et al. Reference Ku, Cho, Kim, Peled, Wiederhold, Wiederhold, Kim, Lee and Kim2003; Sorkin et al. Reference Sorkin, Weinshall, Modai and Peled2006; Weniger & Irle, Reference Weniger and Irle2008; Spieker et al. Reference Spieker, Astur, West, Griego and Rowland2012; Wilkins et al. Reference Wilkins, Girard, King, King, Herdman, Christensen and King2013a , Reference Wilkins, Girard, Konishi, King, Herdman, King, Christensen and Bohbot b ; Fajnerova et al. Reference Fajnerova, Rodriguez, Levcik, Konradova, Mikolas, Brom, Stuchlik, Vlcek and Horacek2014), while others investigated the use of VR in assessing executive functioning (Josman et al. Reference Josman, Schenirderman, Klinger and Shevil2009), self-perception (Landgraf et al. Reference Landgraf, Krebs, Olie, Committeri, Van Der Meer, Berthoz and Amado2010; Synofzik et al. Reference Synofzik, Thier, Leube, Schlotterbeck and Lindner2010) and reality distortion (Sorkin et al. Reference Sorkin, Weinshall and Peled2008). Details of the reviewed studies are listed in Table 2. Taken together, the studies show that VR enables the multimodal assessment of cognitive functioning in ecologically valid environments.

Spatial working memory enables us to integrate various types of information about our environment and to orientate ourselves in it (Olton et al. Reference Olton, Becker and Ge1979). Researchers have used multimodal virtual environments to measure objectively navigation ability, response time and navigation strategy (Ku et al. Reference Ku, Cho, Kim, Peled, Wiederhold, Wiederhold, Kim, Lee and Kim2003; Sorkin et al. Reference Sorkin, Weinshall, Modai and Peled2006). The studies used virtual complex environments (e.g. a courtyard or park) presenting different objects placed in specific areas and instructing the participants to learn and or memorise locations and scenes, with the possibility of controlling and manipulating the neurocognitive task with high reliability. Results are consistent across the studies, showing that participants with schizophrenia spectrum disorders: performed worse than healthy controls (Weniger & Irle, Reference Weniger and Irle2008; Wilkins et al. Reference Wilkins, Girard, King, King, Herdman, Christensen and King2013a ); made more errors and needed a longer time to locate targets than controls (Spieker et al. Reference Spieker, Astur, West, Griego and Rowland2012; Wilkins et al. Reference Wilkins, Girard, Konishi, King, Herdman, King, Christensen and Bohbot2013b ); had more difficulties in pointing and navigating accuracy; and more difficulties in recalling spatial sequences (Fajnerova et al. Reference Fajnerova, Rodriguez, Levcik, Konradova, Mikolas, Brom, Stuchlik, Vlcek and Horacek2014).

Executive functioning is involved in planning, problem solving and the execution of an action or task (Chan et al. Reference Chan, Shum, Toulopoulou and Chen2008). Impairments in executive functioning are associated with poor social functioning and less participation in activities in individuals with schizophrenia (Green et al. Reference Green, Kern, Braff and Mintz2000). Josman et al. conducted a study aimed to examine the validity of a VR Supermarket in the assessment of executive functions (Josman et al. Reference Josman, Schenirderman, Klinger and Shevil2009). Results showed that the VR task had the ability to distinguish between people with schizophrenia and controls and that the group of participants with schizophrenia performed worse on the executive functions associated with the shopping task.

Other neurocognitive domains that have been investigated using VR technology are self-agency and egocentric perception of participants with a diagnosis of schizophrenia (Landgraf et al. Reference Landgraf, Krebs, Olie, Committeri, Van Der Meer, Berthoz and Amado2010; Synofzik et al. Reference Synofzik, Thier, Leube, Schlotterbeck and Lindner2010). Self-agency can be defined as the sense of ownership of one's actions and has been showed to be impaired in psychotic disorders (Kircher & Leube, Reference Kircher and Leube2003). By presenting the participants with complex visual VR environments, researchers were able to conclude that people with psychosis present difficulties when maintaining a non-egocentric perspective and when switching between egocentric and non-egocentric views (Landgraf et al. Reference Landgraf, Krebs, Olie, Committeri, Van Der Meer, Berthoz and Amado2010), as well as some impairments in attributions of agency when non-visual feedback is provided (Synofzik et al. Reference Synofzik, Thier, Leube, Schlotterbeck and Lindner2010).

The perception of reality is subjective, and previous studies have demonstrated that reality distortion is common in psychosis (Liddle, Reference Liddle1987). Sorkin et al. (Reference Sorkin, Weinshall and Peled2008) aimed to use VR to measure distortion in reality perception in people with schizophrenia. Participants were exposed to a VR environment in which they had to identify visual incongruities (e.g. a tree with blue leaves). Results showed that 88% of the participants with schizophrenia failed in the task, while the non-clinical participants detected incongruities successfully.

Assessing functional capacity and social cognition and social competence

Both the research and clinical community have put special emphasis on the improvement of functional disability and social functioning in people with psychosis. The term functional capacity encompasses areas, such as employment, residential or financial independence (Harvey & Bowie, Reference Harvey and Bowie2005). Social functioning can be described as the combination of social cognition [which refers to the mental operations and capacities that underlie social interactions (Green & Leitman, Reference Green and Leitman2008)] and social competence [which refers to communication skills, e.g. the verbal and non-verbal communication skills that allow successful execution of interpersonal interactions (Dickinson et al. Reference Dickinson, Bellack and Gold2007)].

The first attempt to use VR to measure functional capacity in people with psychosis was conducted by Kurtz et al. (Reference Kurtz, Baker and Astur2006) who assessed the relationship between executive function impairments and medication management skills by using a VR apartment. Results showed that people with schizophrenia made more errors, i.e. took incorrect numbers of pills and at the incorrect time compared with the non-clinical controls. More recently, researchers have focussed on the utility of VR as an ecological valid method to place individuals into everyday situations, such as supermarkets or bus and shopping centres, to study real-time deficits in functional capacity and their relationship to cognitive impairments (Ruse et al. Reference Ruse, Harvey, Davis, Atkins, Fox and Keefe2014; Greenwood et al. Reference Greenwood, Morris, Smith, Jones, Pearman and Wykes2016). The findings confirmed that individuals with schizophrenia have poorer real-time function compared with healthy controls. Furthermore, these two studies have also shown that VR can be as reliable and valid as well-established neurocognitive batteries [such as MATRICS (Measurement and Treatment Research to Improve Cognition in Schizophrenia) (Nuechterlein et al. Reference Nuechterlein, Green, Kern, Baade, Barch, Cohen, Essock, Fenton, Frese, Gold, Goldberg, Heaton, Keefe, Kraemer, Mesholam-Gately, Seidman, Stover, Weinberger, Young, Zalcman and Marder2008; Ruse et al. Reference Ruse, Harvey, Davis, Atkins, Fox and Keefe2014)] and real-life situations (Greenwood et al. Reference Greenwood, Morris, Smith, Jones, Pearman and Wykes2016) to assess functional capacity outcomes.

Five studies have explored the utility of VR technology to study different aspects of social cognition: social perception (Ku et al. Reference Ku, Jang, Kim, Park, Kim, Kim, Nam, Kim and Kim2006; Kim et al. Reference Kim, Kim, Kim, Park, Jang, Ku, Kim, Kim and Kim2007; Park et al. Reference Park, Kim, Ku, Jang, Park, Kim, Kim and Kim2009a ) and emotion recognition (Dyck et al. Reference Dyck, Winbeck, Leiberg, Chen and Mathiak2010; Gutierrez-Maldonado et al. Reference Gutierrez-Maldonado, Rus-Calafell, Marquez-Rejon and Ribas-Sabate2012). Studies on social perception have demonstrated that virtual agents can be used to assess potential deficits in expressing emotions (Ku et al. Reference Ku, Jang, Kim, Park, Kim, Kim, Nam, Kim and Kim2006), deficits in the perception of incongruent social emotional cues (Kim et al. Reference Kim, Kim, Kim, Park, Jang, Ku, Kim, Kim and Kim2007) and high social anxiety when meeting others (Ku et al. Reference Ku, Jang, Kim, Park, Kim, Kim, Nam, Kim and Kim2006; Park et al. Reference Park, Kim, Ku, Jang, Park, Kim, Kim and Kim2009a ). Furthermore, both studies from Dyck and colleagues and Gutierrez-Maldonado et al. demonstrated that virtual faces were as valid as natural faces (photographs) to assess emotion recognition ability in people with psychosis; the dynamic component of the VR images was found to be a clear advantage over static images to display human faces (Gutierrez-Maldonado et al. Reference Gutierrez-Maldonado, Rus-Calafell, Marquez-Rejon and Ribas-Sabate2012). Park et al. (Reference Park, Kim, Ku, Jang, Park, Kim, Kim and Kim2009a , Reference Park, Ku, Kim, Jang, Kim, Kim, Kim, Lee, Kim and Kim b ) studied objective parameters of physical distance in individuals with schizophrenia in comparison to healthy controls by using virtual agents in a VR social environment (Park et al. Reference Park, Ku, Kim, Jang, Kim, Kim, Kim, Lee, Kim and Kim2009b ) and found that participants with schizophrenia tended to keep more physical distance and have deviation of eye gaze than non-clinical controls.

Assessment of paranoid ideation and auditory hallucinations

Eighteen studies have used VR to assess paranoid ideation and one study investigated using VR to assess auditory hallucinations. The value of VR for studying paranoid thinking rests on the assumption that programming an environment in which the degree of hostility that the virtual characters display can be manipulated (e.g. to be neutral, benign or hostile) allows a more valid assessment of paranoia than self-report methods, where it is not known whether the hostile intent reported as experienced by the patient is accurate or not (Freeman et al. Reference Freeman, Garety, Bebbington, Slater, Kuipers, Fowler, Green, Jordan, Ray and Dunn2005). Details of the studies reviewed are listed in Table 4.

Freeman and colleagues have been at the forefront of researching paranoid ideation using VR. In their first investigation, participants from the general population were asked to explore a virtual library and to form an impression of what the avatars in the library thought about them. Results showed that participants attributed mental states to the avatars and that real-time paranoid ideation during VR was associated with anxiety, timidity and perceptual abnormalities (Freeman et al. Reference Freeman, Slater, Bebbington, Garety, Kuipers, Fowler, Met, Read, Jordan and Vinayagamoorthy2003, Reference Freeman, Garety, Bebbington, Slater, Kuipers, Fowler, Green, Jordan, Ray and Dunn2005). Subsequently, this research group developed a new virtual environment simulating a London Underground train, which included several avatars (e.g. people reading the newspaper, people standing up, people coming in and out of the train, etc.). The underground environment has been used by researchers to explore persecutory ideation in a number of studies in non-clinical participants (Freeman et al. Reference Freeman, Gittins, Pugh, Antley, Slater and Dunn2008a , Reference Freeman, Pugh, Antley, Slater, Bebbington, Gittins, Dunn, Kuipers, Fowler and Garety b , Reference Freeman, Pugh, Vorontsova, Antley and Slater2010) and clinical populations, including individuals at ultra high risk for psychosis (Valmaggia et al. Reference Valmaggia, Freeman, Green, Garety, Swapp, Antley, Prescott, Fowler, Kuipers, Bebbington, Slater, Broome and Mcguire2007, Reference Valmaggia, Day, Garety, Freeman, Antley, Slater, Swapp, Myin-Germeys and Mcguire2015a , Reference Valmaggia, Day, Kroll, Laing, Byrne, Fusar-Poli and Mcguire b ; Shaikh et al. Reference Shaikh, Ellett, Dutt, Day, Laing, Kroll, Pterella, Mcguire and Valmaggia2016) and people with psychosis (Freeman et al. Reference Freeman, Pugh, Vorontsova, Antley and Slater2010; Fornells-Ambrojo et al. Reference Fornells-Ambrojo, Freeman, Slater, Swapp, Antley and Barker2015). The main conclusions drawn from these studies were that paranoid ideation can be readily elicited in VR environments, including where the avatars are programmed to behave neutrally; that the people who had paranoid reactions in the VR environment were more prone than those who did not to internal anomalous experiences (i.e. changes in levels of sensory intensity, distortion of external world) and to self-reported paranoid ideation; and that anxiety, worry and depression were also associated with both social anxiety and paranoia. Recent findings in general population samples have shown that VR can be used to explore paranoid thinking and self-confidence in relation to social comparisons (Atherton et al. Reference Atherton, Antley, Evans, Cernis, Lister, Dunn, Slater and Freeman2014; Freeman et al. Reference Freeman, Evans, Lister, Antley, Dunn and Slater2014), to investigate the effects of THC (Δ⁹-tetrahydrocannabinol) on real-time paranoid ideation (Freeman et al. Reference Freeman, Dunn, Murray, Evans, Lister, Antley, Slater, Godlewska, Cornish, Williams, Di Simplicio, Igoumenou, Brenneisen, Tunbridge, Harrison, Harmer, Cowen and Morrison2015) and to study the relationship between interpersonal contingency, trust and paranoia (Fornells-Ambrojo et al. Reference Fornells-Ambrojo, Elenbaas, Barker, Swapp, Navarro, Rovira, Sanahuja and Slater2016).

Exclusion from a VR cyber-ball game and negative feedback received about the performance during the game was associated with paranoid ideation (Kesting et al. Reference Kesting, Bredenpohl, Klenke, Westermann and Lincoln2013). Previously, this team had also demonstrated the use of a VR cyber-ball game to measure the relationship between emotion regulation techniques (such as suppression or reappraisal) and paranoid ideation (Westermann et al. Reference Westermann, Kesting and Lincoln2012).

Broome et al. designed a walk in a virtual street and showed that levels of paranoid ideation in an urban environment where higher than those previously reported in indoor environments (Broome et al. Reference Broome, Zanyi, Hamborg, Selmanovic, Czanner, Birchwood, Chalmers and Singh2013). Veling et al. (Reference Veling, Brinkman, Dorrestijn and Van Der Gaag2014a ) conducted a pilot study in which participants were asked to walk into a virtual café and report their level of paranoid thoughts while a psychophysiological measure (galvanic skin response) was recorded. The experimenters manipulated the environment by changing the ethnicity of the avatars. The results showed that patients with first-episode psychosis were more likely than healthy controls to report paranoid thoughts when walking close to avatars and that they showed a stronger galvanic response to avatars of a different ethnicity than their own. These results have been recently replicated by the same research group, including siblings of patients and manipulating also the objective distress parameters (population and ethnic density, avatars’ hostility) (Veling et al. Reference Veling, Pot-Kolder, Counotte, Van Os and Van Der Gaag2016).

Moritz et al. (Reference Moritz, Voigt, Köther, Leighton, Kjahili, Babur, Jungclaussen, Veckenstedt and Grzella2014) reported the results of a non-controlled pilot study in which they combined emotion recognition and error feedback for social perception judgements. The one-session feedback intervention resulted in a reduction of paranoid ideation. Although the paradigm used in this study was proposed for assessment, the authors concluded that it might function as a short intervention to reduce negative judgements in social settings.

With regard to auditory hallucination, the virtual London Underground was used to explore the occurrence of auditory hallucinations during VR. While participants reported hearing voices during the VR experiment, no support was found for the role of hypothesised antecedent cognition in triggering voices (Stinson et al. Reference Stinson, Valmaggia, Antley, Slater and Freeman2010).

Treatment

Eight studies were identified investigating the use of VR in the treatment of psychosis. VR has been applied as an adjunctive treatment in cognitive remediation (Chan et al. Reference Chan, Ngai, Leung and Wong2010; Tsang & Man, Reference Tsang and Man2013); to improve job interview skills (Smith et al. Reference Smith, Fleming, Wright, Roberts, Humm, Olsen and Bell2015) and social skills (Park et al. Reference Park, Ku, Choi, Jang, Park, Kim and Kim2011; Rus-Calafell et al. Reference Rus-Calafell, Gutierrez-Maldonado and Ribas-Sabate2014); and in cognitive behaviour (Gega et al. Reference Gega, White, Clarke, Turner and Fowler2013; Leff, Reference Leff2013; Freeman et al. Reference Freeman, Bradley, Antley, Bourke, Deweever, Evans, Cernis, Sheaves, Waite, Dunn, Slater and Clark2016). Details of these investigations are described in Table 5.

Cognitive remediation therapy for psychotic disorders can be defined as a behavioural training-based intervention that aims to improve cognitive processes (attention, memory, executive function, social cognition and metacognition) with the goal of durability and generalisation to functioning in everyday life (Wykes & Spaulding, Reference Wykes and Spaulding2011). One important challenge within cognitive remediation research has been the adaptation of VR tasks to a specific individual needs. Chan et al. (Reference Chan, Ngai, Leung and Wong2010) explored the effect of adapted VR cognitive training in older individuals with a long-term diagnosis of schizophrenia.

Results showed that participants who received the 10-sessions VR intervention had a better improvement in overall cognitive function than controls, who received the usual programme in the clinic. Tsang & Man (Reference Tsang and Man2013) considered the effectiveness of VR as an intervention for enhancing cognitive performance among people with a diagnosis of schizophrenia with the goal of improving their vocational skills. The virtual intervention group engaged in tasks related to work performance in a virtual boutique. Results showed that the group who received the virtual intervention performed better on executive function, problem solving, categorisation, memory, attention and self-efficacy than the therapist-administered group (with the same task content as the VR intervention).

Smith and colleagues also investigated the use of VR to improve job-interview skills and self-confidence. Their finding suggests VR can improve the specific cognitions and behaviours needed for job interviews and employment, with positive results maintained at 6-month follow-up (Smith et al. Reference Smith, Fleming, Wright, Roberts, Humm, Olsen and Bell2015).

Social skills training aims to improve social and interpersonal skills in people who have difficulties in communicating in social situations. In terms of social behaviour improvement and social skills training using VR, two controlled studies were identified. Park et al. (Reference Park, Ku, Choi, Jang, Park, Kim and Kim2011) compared the use of a social skills intervention, i.e. traditional role-play, to a virtual environment where patients with a diagnosis of schizophrenia engage in role-play with virtual persons. All participants received 10 bi-weekly group sessions. Results showed that both groups improved in verbal skills. The virtual intervention was shown to be more engaging than the traditional intervention. Subsequently, Rus-Calafell et al. (Reference Rus-Calafell, Gutierrez-Maldonado and Ribas-Sabate2014) researched the benefits of using VR as adjunctive method for social skills training with patients with psychosis ‘Soskitrain’ resulted in significant improvement in negative symptoms and social avoidance together with an improvement in social skills, in comparison to baseline performance. These gains were maintained at 4-month follow-up (Rus-Calafell et al. Reference Rus-Calafell, Gutierrez-Maldonado and Ribas-Sabate2014).

VR-assisted therapy for paranoia and hallucinations. To date, two proof-of-concept studies have investigated the use of VR-assisted therapy for paranoia and one pilot study investigated using VR to treat people with auditory hallucinations. Gega et al. conducted a proof-of-concept study to test whether VR could be integrated with a 12-week cognitive–behavioural treatment (CBT) programme for people with paranoia and social anxiety. One VR session was embedded in a 12-week course of CBT. In the VR session, patients were able to practice social interactions with avatars in a variety of social situations. Avatars could be hostile, neutral or friendly and asked patients innocuous or personal questions. Results showed that the VR-assisted intervention reduced social anxiety and paranoia at 24-week follow-up (Gega et al. Reference Gega, White, Clarke, Turner and Fowler2013).

Freeman and colleagues have also conducted a proof-of-concept study in which they investigated encouraging people with long-standing persecutory delusions to test their threat beliefs and drop their safety behaviours in a VR underground and a VR lift. This one session intervention led to a significant decrease of delusional conviction in the participants (Freeman et al. Reference Freeman, Bradley, Antley, Bourke, Deweever, Evans, Cernis, Sheaves, Waite, Dunn, Slater and Clark2016).

AVATAR therapy uses a non-immersive VR system to enable people with auditory hallucinations to challenge their beliefs about the power of the voices and gain more control over the voices they hear. Participants are asked to create an avatar of the entity that they believe is talking to them. They then engage in a dialogue with the avatar of their voice, which the therapist is able to control. A pilot study indicated that patients are able to engage in the dialogue with a virtual voice and the experimental group was found to have an overall reduction in mean scores of auditory hallucinations (Leff, Reference Leff2013).