Work-related mental health problems are one of the main causes of work leave within the countries of the Organization for Economic Co-operation and Development [1]. Research carried out by the European Agency for Safety and Health at Work shows that 28% of employees recognized having suffered stress in their working place; in addition, it is estimated that stress is the main factor in 50% to 60% of lost working days [2-3]. The increased pace at the workplace and in everyday life is dramatically increasing the number of stressful situations to which people are exposed [4].

Stress is strongly associated with mental health problems such as depression [2]. Preventive treatments for high-risk individuals have proven successful in reducing pathologies associated with mental health problems as a consequence of high stress levels [5-6]. Stress management therapy programs are usually focused on teaching individual techniques for stress relief and generally extend several weeks or months [7-8]. A very small portion of the public health budget is allocated for medical problems associated with stress, with an even smaller amount allocated for preventive interventions [9]. New tools to facilitate welfare self-management should be accessible wherever and whenever they are needed. Stress management therapy refers to the techniques used by therapists, doctors, and psychiatrists who help stressed persons relieve their tension and stress. Some stress management therapies include interaction, biofeedback, relaxation, cognitive behavior therapy (CBT), and different exercises (yoga or meditation) [8].

Personal health technologies look promising in order to support people in health and welfare self-management. For example, several studies have gathered positive impact in the use of Web-based therapies for the treatment of health problems related to stress and anxiety [8-13].

Web-based therapies are accessible 24/7 and can be customized depending on user needs and allow the user to avoid the embarrassment of visiting a professional. The British National Health System (NHS) offers patients 2 different Web-based CBTs, but browser-based interventions aren’t as attractive now that mobile apps have become popular [14-16].

User response in terms of estimated delay is characterized by the time window data-cleaning [17-19]. Response times depend on geography, platform (Android or iOS), and other factors. Other authors study mobile device-to-device video distribution that leverages the storage and communication capacities of smartphones [19].

This research tries to study in depth the status of stress-related mobile apps and the different therapies and methodologies being used and tries to forecast the patterns that will define stress-related mobile apps in the near future. In this paper, the apps have been divided into different categories such as self-help, heart rate control, integral methodology for the management and prevention of stress, hypnosis, games, images, meditation and breathing, relaxing music, draw and paint, yoga, guided relaxation, and others. This classification has followed the criteria of the authors and the queries to users.

In this study, 24 keywords were chosen. On June 2017, 48 searches were carried out in the Spanish and English virtual stores of the 2 main operating systems for mobile phones, Google Play and App Store. Eight searches returned no results. The remaining 40 searches returned a total of 1000 apps, with 606 being relevant (see Figure 1) and 433 unique. Characteristics of these 433 unique apps were recorded, and the apps were categorized.

The 15 most relevant apps have been chosen from the “Most relevant” category in the app stores. If more than 5 consecutives apps were identified as not relevant (eg, games), the apps chosen for that search were limited at all the previous results excluding those 5.

The following information was recorded for each app: country, language, operating system, and free or pay per use. Additionally, after we installed and tested them, all the apps were sorted according to different categories (see Table 1).

After the apps were recorded, they were scored based on the following criteria:

Some of the apps with higher scores were analyzed in depth in order to identify the methodology used in their design.

In this section, we analyze stress-related mobile apps currently available in the United Kingdom and Spain. A total of 433 different apps were installed, tested, analyzed, categorized, and scored.

As can be seen in Table 1, about one-fifth (94/433, 21.7%) of the apps belong to the “relaxing music (songs, natural sounds)” category, and these apps included either relaxing songs or sound that are typically associated with relaxation and inner peace like sea, rain, mountains, or lakes. Mandalas have become well known thanks to the media in the last several years and represent most of the 10.9% (47/433) of apps in the “draw and paint” category.

Apps about integral methodology are based on CBTs including cognitive therapy, problem-solving therapy, dialectical behavior therapy, metacognitive therapy, rational-emotive behavior therapy, cognitive processing therapy, mindfulness-based cognitive therapy, cognitive-behavioral analysis system of psychotherapy, and schema-focused therapy.

Of note, 6 apps focused on guided relaxation are also included in the 15 most relevant apps. Its 10 points of median with a standard deviation of 6.77 proved that despite having 6 high scoring apps in this group, most of the apps obtained the minimum possible score points.

When the apps were categorized and relevance was evaluated, only 1.8% (8/433) of the apps qualified as high or medium interest while 98.0% were low interest (Table 2).

Only 1.8% (8/433) of the apps are available in both iOS and Android environments (Table 3). Android is the world's most popular mobile platform. According to Gartner [20], Android and iOS accounted for 99.6% of all mobile phone sales in the fourth quarter of 2016. Many apps only run on one platform (Android or iOS), and this is true with health care apps as well.

This study also focused on analyzing the country and language where the apps were found; 46% of the apps were only found in the Spanish store. Only 2% of the apps were available in both Spain and the United Kingdom, even though it is well known that most of the app developers publish their apps in more than 1 country at a time. This is probably happening due to the high number of different apps offered, where being in the top 25 relevant apps in getting more difficult.