# Usability and Affects Study of a Virtual Reality System Toward Scorpion Phobia Exposure Therapy
## 1 Introduction  
A phobia is characterized by the presence of uncontrollable anxiety that is not consistent with real risk and affects the daily life of a person [1, 2]. Specific phobias are considered the most common anxiety disorders, and their causes, consequences, and treatments require further research [3]. The estimated lifetime prevalence of these disorders ranges from 3% to 15%, with phobias of heights and animals being the most common [4, 5]. One of the most feared animals by humans are spiders and, although their medical importance is indisputable, there is a significant amount of misinformation about this and other archnids, such as scorptions [6, 7, 8]. Hence, acathonphobia has been the most common specific phobia for research topics, being the most studied [9]. Cognitive behavioral therapy (CBT) is the current gold standard for treating specific phobias, especially those related to insects [10, 11]. CBT has been used with graded exposures to the phobic stimulus in different contexts and non-aversives. On the other hand, exposure therapy (ET) is a type of behavioral therapy, also considered a standard treatment for specific phobias such as aranchophobia, and it is estimated that 75% of patients receive clinical benefit compared to placebo [12]. ET extinguishes the conditioned fear by creating a safe environment, in which the patient is exposed to the feared stimulus repeatedly over time, to decrease the fear [13]. However, even though ET is considered the most effectiveway to treat specific phobias, there are patients who do not respond to ET, and many phobic patients refuse treatment or discontinue treatment during the process [14]. Virtual reality exposure therapy (VRET) is an emerging technology that psychotherapists have recently used in therapy designs and settings using sensory stimulation to generate an interactive perception of a realistic, immersive, and controlled virtual world [15; 16; 17]. VRET, employing various scenarios and integrating monitoring equipment, has provided evidence of its effectiveness, reliability, and validity [18]. Several VRET systems for the treatment of spider phobia have been described in the literature over time [19; 20; 21; 22], highlighting advantages such as continuous exposure of individuals to the object of their fear [23] and better control of anxiety due to the absence of a real threat [24]. In some cases, participants showed a reduction in both subjective anxiety and spider cognitions in a more comfortable way than in vivo exposure therapy (IVET). In the same way, it is complicated to have a real spider for IVET, as it is a process that consumes the time and resources of the therapist [25]. For the purposes of realism, controlled interaction, and time-consuming reduction, in some cases VRET has presented highly effective treatments over CBT or IVET for a broad spectrum of mental health conditions [26; 27; 28]. In addition, the use of VRET allows for the exposure of patients to the phobic environment to be adjusted to reduce the additional harm that can be caused by stress and panic attacks resulting from overexposure [29]. Recently, it has been suggested that spider fear may be the consequence of a more general fear of chelicerates, of which the scorpion is the main model [30; 31]. Scorpion venom represents a health problem in several parts of the world and it can cause serious medical complications and untimely death if it is injected into the human body [32]. Mexico is home to the greatest diversity of scorpions in the world (around 12%), including some of the most medically important species [33]. Although efficient results and advances in these systems have been documented, most have focused on spiders, as opposed to scorpions, as we have undertaken in this work. In [34], we found a study in which the behavioral and psychophysiological influence of conscious access and recognition of fear of scorpions was studied.