[Virtual reality exposure therapy for post-traumatic stress disorders, obsessive-compulsive disorders and anxiety disorders: Indications, added value and limitations].

The exposure in cognitive behavioral therapy (CBT) is a well-known intervention, widely investigated in scientific research. Several studies have shown the benefits of this intervention in the treatment of anxiety disorders, obsessive-compulsive disorders (OCD) and post-traumatic stress disorders (PTSD). The different exposure techniques are mainly based on the emotional processing of fear theory and use an emotional stimulation of fear, following by its habituation. However, new approaches have emerged and are based on the inhibitory learning theory. The virtual reality technology allows emotional involvement from patients and represents a complementary approach to the classical modalities of exposure therapy (e.g., mental or in vivo expositions). This modern approach presents specific features that need to be taken into account by the therapist. Firstly, the presence feeling, which is defined as the "be there" feeling. This feeling is dependent on immersive technical features and personality factors. Secondly, virtual reality sickness, similar to motion sickness, represents a limitation that might prejudice a virtual therapy. The main scientific investigations of Virtual Reality Exposure Therapy (VRET) for treating social phobia, specific phobia, PTSD, and panic disorders are encouraging and demonstrate a similar effectiveness between both in vivo and in virtuo exposures. The scarce investigations on generalized anxiety disorders and OCD also suggeste a similar effectiveness between these exposures. However, further scientific investigations are needed to support these preliminary findings. The attrition rates and deteriorating states are similar to classical CBT approaches. Nevertheless, scientific literature presents several limits: 1) much of the research on this topic has interest conflicts (e.g., developers are also authors of a large number of studies); 2) there is a high heterogeneity of materials and virtual environments used; 3) important measures are not always taken into account in scientific research (e.g., the presence feeling); and 4) a massive use of waiting lists as a control measure. Despite these limitations, the VRET have strong silver linings: 1) the easy access to exposure (less limited than standard exposure techniques) and a cost reduction; 2) highly guaranteed security; 3) the anonymization of exposures (i.e., the patients do not risk meeting someone they know during the exposure therapy); 4) the therapist has a greater control of exposures; 5) a standardization of the exposures; 6) a greater involvement in therapy for technophile patients. Virtual exposure also seems to be generally more accepted by patients.