Table 2.

Examples of systematic reviews and meta-analyses demonstrated the use of VR in treating PTSD and anxiety disorders.

Author and year	Study aims	Studies included and sample (n)	Study outcomes	Points of discussion
PTSD
Kuester et al. (2016)	Examined the efficacy of internet-based CBT and expressive writing in people with PTSD vs. waitlist or active controls.	20 studies (n = 973 intervention, 805 controls)	Internet-based CBT are showed medium to large effect sizes compared to passive controls, but not against active controls receiving face-to-face CBT with therapist.	Internet-based CBT may be just as beneficial as conventional CBT.
				Due to large variability in outcome measures of included studies, subgroup analyses was limited.
Goncalves et al. (2012)	A systematic review of the efficacy of VR exposure therapy in the treatment of PTSD vs. waitlist or active controls.	10 studies (n = ?)	Patients in VR exposure therapy showed insignificantly better results compared to waitlist controls, but no differences was observed when compared to exposure therapy.	Preliminary evidence suggests that VR exposure therapy is just as efficacious as conventional CBT.
			Majority of VR exposure therapy used head-mounted displays and customized virtual environment specific to the condition.	Studies included did not use intent-to-treat analysis or did not state concomitant treatments and/or comorbidities.
			No difference in dropout rates between VR therapy and conventional CBT.
Anxiety disorder
Opris et al. (2012)	Treatment efficacy of VR exposure therapy vs. conventional CBT in anxiety disorders vs. active controls.	23 studies (n = 608)	VR therapy was significantly better than waitlist controls.	The use of VR exposure therapy may be a viable option.
			Similar improvements were observed between VR and conventional CBT therapy.	There is a future need to determine the use of VR exposure therapy to other forms of VR therapies targeted at anxiety disorders.
			Similar improvements in outcome measures were maintained over time in both the VR and conventional CBT groups.	No measure of dropout rates in studies reviewed.
Powers and Emmelkamp (2008)	Examined the effects of VR in anxiety disorders vs. waitlist or conventional CBT controls.	13 studies (n = 397)	VR therapy was more efficacious that waitlist or active control.	VR exposure therapy was highly effective in treating anxiety disorders.
			Significant improvements were observed in subjective distress, cognitive and behavioral measures, and psychophysiological measures.	Behavioral avoidance tests should be administered to assess the impact of treatment on anxiety-provoking situations and generalization to the real world.
			VR therapy was more effective than in vivo exposures.
			Non-significant trend toward a dose-response relationship was observed between number of sessions and outcome measures.

CBT, cognitive behavioral Therapy; PTSD, post-traumatic stress disorder; VR, virtual reality.