واقعیت مجازی و هذیان های آزار و شکنجه: ایمنی و امکان سنجی

Objective Virtual reality (VR) has begun to be used to research the key psychotic symptom of paranoia. The initial studies have been with non-clinical individuals and individuals at high risk of psychosis. The next step is to develop the technology for the understanding and treatment of clinical delusions. Therefore the present study investigated the acceptability and safety of using VR with individuals with current persecutory delusions. Further, it set out to determine whether patients feel immersed in a VR social environment and, consequently, experience paranoid thoughts. Method Twenty individuals with persecutory delusions and twenty non-clinical individuals spent 4 min in a VR underground train containing neutral characters. Levels of simulator sickness, distress, sense of presence, and persecutory ideation about the computer characters were measured. A one-week follow-up was conducted to check longer-term side effects. Results The VR experience did not raise levels of anxiety or symptoms of simulator sickness. No side effects were reported at the follow-up. There was a considerable degree of presence in the VR scenario for all participants. A high proportion of the persecutory delusions group (65%) had persecutory thinking about the computer characters, although this rate was not significantly higher than the non-clinical group. Conclusions The study indicates that brief experiences in VR are safe and acceptable to people with psychosis. Further, patients with paranoia can feel engaged in VR scenes and experience persecutory thoughts. Exposure to social situations using VR has the potential to be incorporated into cognitive behavioural interventions for paranoia.

Presence in virtual reality (VR) occurs when a person has a sense of being in the place depicted by the VR system and responds realistically (Sanchez-Vives and Slater, 2005). This has been exploited in the treatment of anxiety disorders by exposing patients to virtual environments related to their fears (e.g. Difede and Hoffman, 2002, Emmelkamp, 2002, Garcia-Palacios et al., 2002 and Rothbaum et al., 2000).Intriguingly, people have been found to respond to computer-generated characters (avatars) as if they were social agents (Garau et al., 2005 and Pertaub et al., 2001), even in extreme social situations (Slater et al., 2006). Subsequently, individuals' reactions to avatars have been used to investigate paranoid thinking, a key symptom of psychosis (see review by Freeman, 2008). Paranoia exists on a continuum in the general population, ranging from mistrust to clinical persecutory delusions (e.g. Combs and Penn, 2004, Fenigstein and Vanable, 1992 and Freeman, 2007). VR has several key advantages in studying paranoia. If individuals are presented with a neutral social situation, then any paranoid thinking that occurs is known to be unfounded. Moreover, the participant's own mistrustful or unusual behaviour cannot elicit hostile responses from the avatars. Further, if patients do experience paranoid thoughts in virtual reality then this offers the possibility of the technology being incorporated into the emerging cognitive behavioural treatments (Freeman et al., 2006). In the initial reports virtual reality has been used to study persecutory ideation in the general population (e.g. Freeman et al., 2008) and those at high risk of psychosis (Valmaggia et al., 2008). The validity of the methodology has been shown by higher levels of trait paranoia being associated with the occurrence of persecutory ideation in VR. Of theoretical interest these studies have consistently shown that persecutory ideation in VR is predicted by anxiety, worry, interpersonal sensitivity and perceptual anomalies. The main aim of the present study was to investigate if it was feasible to use immersive VR with people with psychosis who have current persecutory delusions. We predicted that VR would be safe and acceptable to people with persecutory delusions. Safety was operationalised as the absence of an increase in level of anxiety, no triggering of significant levels of simulator sickness, and no adverse experiences in the following week. Simulator sickness refers to symptoms similar to motion sickness (e.g. nausea, dizziness) that can sometimes be caused by virtual environments because the visual system indicates movement while the balance mechanisms in the inner ear register no movement. The secondary aims of the study were to examine whether people with persecutory delusions could be immersed in a VR social scene (i.e. experience presence) and whether they would have paranoid thoughts about neutral avatars. We also hypothesised that people with persecutory delusions would be more likely to report paranoid thoughts in VR than non-clinical volunteers.