Individuals suffering from depression are more likely to develop comorbidity with other mental disorders, an estimated 53% have concurrent symptomatology with some anxiety disorder (Weisel et al., 2018). Stress and traumatic events are among the most relevant causes, between 60% and 80%, contributing to the etiology of emotional disorders. Depression and anxiety have also been deemed to create a condition of greater disability by increasing the severity and chronicity rate of psychological discomfort and is associated with increased mortality in medical conditions such as heart disease, chronic-degenerative or psychiatric conditions (Berenzon et al., 2013). In Mexico, one in four people between the age of 18 and 65 has suffered an emotional disorder at some point in their lives, but only one in five of those with it receive treatment and the time to receive care in a health center ranges from 4 to 20 years depending on the reason for consultation (Berenzon et al., 2013).

In recent decades, cognitive behavioral interventions, from a disorder-specific perspective, constitute an effective and first-line treatment for anxiety and depression care (Cuijpers et al. 2014; Kazdin, 2016); They highlight: a) exposure therapy; b) anxiety management techniques; and c) cognitive therapy, however, however they are not often used (Mohr et al., 2010). In this regard, a number of reasons have been noted explaining limited access and low availability to effective interventions. A minority of people actively seek psychological care because of their own condition of emotional discomfort, fearing social stigma, because of geographical reasons that separate them from health centers, because of reasons of time, preference for other treatment or self-help, because of the high cost of psychological support, which makes it inaccessible and unaffordable to both, the user and the public health system (Berenzon et al., 2013). It has also been argued that the comorbidity between mental disorders, as well as the gap between research findings and clinical practice could influence the poor dissemination of effective treatments; resulting in a lack of up-to-date professionals providing relevant interventions (Holmes, Craske \& Graybiel, 2014). In the same line, Kazdin and Blase (2011) mention that, despite advances in research, mental health professionals have been unsuccessful in reducing the incidence and prevalence of emotional disorders. This has motivated studies aimed at knowing the moderating, mediating variables and psychological mechanisms that improve the process of clinical change (Ebert et al., 2018). In addition, the need has been raised to implement innovative solutions that contribute to the dissemination of effective treatments for the care of emotional disorders( Kazdín \& Rabbitt, 2016).

Faced with this problem, psychological rehabilitation of people diagnosed with depression and anxiety has been found to be mediated by the primary assessment of the event that can be perceived as threat, challenge, or benefit; estimation of control over adverse or stressful stimulus and the resources available to deal with the situation (Folkman \& Moskowitz, 2007). In particular, emotional deregulation of negative affection is a study factor that is providing relevant data for better understanding and approaching emotional disorders from a transdiagnostic perspective, a term coined from a dimensional conception to designate effective treatments targeting two or more specific disorders (Hernández et al., 2011).

This has crucial implications for the possible diagnosis of emotional disorders, since, from a dimensional perspective, consideration of the causes and coping resources that the person has and not only the count of prescribed grouped symptoms takes on relevance. The degree of intensity and effects on the day-to-day functioning of the person are also taken into account. For treatment purposes, it addresses common or shared risk factors between disorders (e.g. emotional disorders), including underlying mechanisms, psychological (cognitive, behavioral and physiological) processes linked to explanatory variables and maintenance of overlapping symptoms (attentional biases, negative thinking, avoidance, etc.), appealing to a convergent and integrative scientific approach (Sandin, 2014). Thus, transdiagnostic treatments could help overcome the disadvantages related to comorbidity between disorders and thus make way for a new generation of emotion-focused treatments (Hernández et al., 2011). In this regard, Barlow, Allen and Choate (2004) return to the tripartite theory of emotion (Clark \& Watson, 1991) and propose a unified cognitive-behavioral transdiagnosis protocol for the treatment of emotional disorders with an emphasis on emotional regulation.

On the one hand, there is evidence of effective transdiagnostic interventions for the treatment of emotional disorders that help overcome the disadvantages related to comorbidity between disorders; and on the other hand, the benefits shown by interventions provided over the Internet and mobile applications by allowing: (1) accessibility: easy access anytime and from anywhere over the Internet, (2) flexibility: the intervention adapts to the participant's pace and the consultation of resources and materials can be asynchronous, (3) customization: the intervention can be adapted to the specific needs of the user, (4) availability of treatment: it allows to bring psychological care to people who need it regardless of distance, which is an alternative when it is not possible to access face-to-face mental health services. In addition, (5) scalability, as it can increase coverage and improve care as technology advances (Díaz-García, 2017; Weisel et al., 2018). Therefore, transdiagnostic interventions focused on the emotion provided online involve enhancing the scope and impact of psychological treatment programs for anxiety and depression (Titov et al., 2013).

While there is evidence of effectiveness, aimed at knowing the impact of the outcome of treatment, other relevant aspects that has not been sufficiently explored are the risk and/or protection factors that cause moderation and mediation effects with respect to the results obtained in treatments (Graaf et al., 2002) for example, to know the profiles that benefit most from interventions (Brookes et al., 2004; Kessler et al., 2017). Identifying variables that moderate or mediate the impact of treatment is important because it could support understanding the heterogeneity of the results. Evidence of the effectiveness of preventive and/or remedial interventions over the Internet in the context of public health for the reduction of the incidence of depressive and anxious symptomatology is still low; the latest systematic review identified seven uncontrolled clinical studies that evaluated the effect of internet-mediated interventions with positive results (Ebert et al., 2017). However, only one clinical study aimed at preventing general anxiety was found that did not produce significant results (Christensen et al., 2014). While three studies managed to reduce the incidence of depression (Buntrock et al., 2016; Dear et al., 2016). In the study conducted by Dear et al. (2016) reported that self-applied internet-guided intervention decreased depressive symptomatology in a group of adults and managed to reduce the risk of chronic depression by 39% per follow-up year. Recent research on the effectiveness of self-applied interventions via the Internet with and without the support of a trained psychologist has indicated that fully self-applied technology-mediated treatments show fewer rates of improvement compared to those who did have synchronous support with a therapist (Richards \& Richardson, 2012). Other studies that have researched the influence of support or guidance during self-applied internet-based interventions have reported that participants who received weekly support significantly improved in reducing depression compared to a waiting list group, while participants who did not receive support did not show significant improvement (Kleiboer et al., 2015). However, some authors propose that the differences in results obtained between guided and non-guided interventions are small or non-existent (Mira et al., 2017). This aspect is relevant for assessing the efficiency of interventions provided with technology, as they could benefit more people who need it with effective results. In general, the research findings mentioned are promising; however, it is also important to note that most studies have been conducted in developed contries, so it is necessary to know the results in controlled studies in the Mexican context and culture and with larger samples to reach stronger conclusions regarding the effectiveness, efficacy and efficiency of transdiagnostic interventions via the Internet for the care of emotional disorders. In addition, it is necessary to investigate what are the suitable applications of the technology, whether or not there is a significant benefit using this technology compared to other strategies that are currently available, and what factors can contribute to these effects (Quero et al., 2012).

In Mexico, research in this area is incipient, emphasizing the need to go beyond traditional face-to-face interventions and to design new intervention strategies. In this regard, the possibilities offered by technologies are highlighted since Internet-supported interventions have been empirically tested to achieve effectiveness and efficiency/cost-benefit and can be key to ensuring access to those who are inaccessible. Thus, in consistency with the National Health Plan, this study aims to respond to this national problem through the evaluation of the effectiveness and moderators of a transdiagnostic intervention for emotional disorders through a telepsychology system.