Can virtual reality scenarios induce acute anxiety within an experimental setting?

The noradrenergic system is engaged by arousal and novel stimuli, and has a widespread influence throughout the body, indirectly innervating areas that control heart rate, respiratory rate, perspiration rate, pain sensitivity, and pupil diameter. This study aimed to create anxiety using threatening virtual reality protocols and determine whether that anxiety was sufficient to cause physiological responses consistent with locus coeruleus activation and thus noradrenaline release. Ten participants were exposed to three different types of virtual reality protocol (relaxing, implied threat and overt threat) and one mental arithmetic protocol, each designed to elicit a different level of anxiety for comparison. Anxiety level was assessed after each protocol using a five-point Likert scale, with a minimum of 1 (not anxious at all) and maximum of 5 (extremely anxious). While experiencing these protocols pupil diameter, pressure pain threshold, heart rate, and galvanic skin resistance were recorded. These autonomic and sensory measures are known to be influenced by locus coeruleus activation and noradrenaline release. Increases in pupil diameter, in particular, are correlated with locus coeruleus activity. Virtual reality threat protocols were successful in promoting anxiety in participants, however, the mental arithmetic protocol created greater anxiety. Virtual reality threat protocols resulted in significant increases in two of the outcome measures (pupil diameter and pressure pain threshold) and had a median anxiety score of ≤ 2.5, while mental arithmetic resulted in significant changes in three of the outcome measures (pupil diameter, pressuanixre pain threshold, galvanic skin resistance) and a median anxiety score of 3. Exploratory repeated measures correlations showed that pupil diameter correlated with pressure pain threshold (rrm = 0.27 [0.029, 0.49], p = 0.03), pressure pain threshold with galvanic skin resistance (rrm = -0.3 [-0.5, -0.075], p = 0.01), and galvani