Anxiety, Depression and Quality of Life in Industry 4.0: A literature review

— With an increasingly competitive labor market and rising unemployment rates, inadequate working conditions such as: low wages, unhealthy environments, excessive noise and heat, accumulation of functions, excess working hours and regime in different shifts, are factors that may contribute to the emergence of mental and behavioral disorders. In order to carry out this study, a systematic literature review was carried out using the Methodi Ordinatio method, through the following steps: selection of databases; definition of keywords and their combinations; definition of search criteria; extraction of searches from databases; elimination of duplicate articles; definition and application criteria for the exclusion of articles that are not compatible with the proposed theme. It was possible to identify that there is a low number of scientific productions that address the themes of quality of life, anxiety and depression, and industry 4.0, which is an opportunity for future studies.


INTRODUCTION
The absence of workers at their place of work is converted into reduced productivity, such data, known as absenteeism, is associated with delays, reduced individual performance and turnover (JOHNS, 2010). The employee, when presenting at work affected by a disease, and with a drop in performance due to health problems, is related to presenteeism (SCHULTZ, 2007).
According to Harnois & Gabriel (2000) the weight of mental health disorders on health and productivity has been underestimated over time. According to researchers from the UK Department of Health and the British Industrial Confederation, they estimated that between 15-30% of workers will experience some form of mental health problem throughout their careers. Mental health problems are the leading cause of illness and disability, among the main disorders are depressive disorders, which predominate in the United States workforce.
The science that investigates mental health in the industrial environment is called industrial psychology, and the entire development of industrial psychology and industrial sociology Elton Mayo (1945), initially studied the effects of workers' physical conditions on productivity, and the reason for constant conflicts between workers and employers that impacted productivity.
Human relations, whether man to man, or man with machine and material, occupy a complex space in the industrial enterprise. Regardless of mechanization, machines must be designed, operated, and supervised by man, and the study of this human behavior, aims to provide support for increasing efficiency and reducing production and distribution costs (VITELES, 1955;MYERS, 1922).
In order to remain competitive, companies demand beyond the human capacity, the fulfillment of previously established goals, which lead them to the search for survival, in this way, employees and managers enter an immersive state at work, feeling the limit of their own abilities at face new goals, which end up generating more anxiety, fear and anguish (DOWNS, 2000;MOTTA, 2012).
When analyzing the industrial transition scenario that takes place in the 21st century, it is necessary to investigate the mental health and quality of life of the The present work is structured as follows: after this introduction, the theoretical basis is carried out regarding the concepts that underpin the research, followed by the methodological procedures used in carrying out the research. Finally, the analysis and discussion of the data is presented, ending with the final considerations of the work, its limitations and suggestions for future research.

Industry 4.0
Industry is a part of the economy that produces material goods, which are highly mechanized and automated, and since the beginning of industrialization technological advances have led to changes in paradigms, known as "industrial revolutions". The first industrial revolution was due to the use of mechanics, while the second industrial revolution was due to the intensive use of electric energy, while the third industrial revolution was due to the widespread use of digitalization, and finally, in the 21st century the era in which we combine internet technology and "smart" objects with manufacturing, known as Industry 4.0 (LASI, 2014). Understood as a new industrial stage, industry 4.0 integrates manufacturing operating systems and information and communication technologies, especially the Internet-of-Things (IoT), a cloud system, forming the concept Cyber-Physical Systems for industry 4.0 (WANG, 2015). Cyber-Physical Systems are considered as physical artifacts controlled, monitored, coordinated and integrated into networks by an embedded system. This embedded system is a combination of hardware and software components, connected in an environment through sensors, to perform predefined tasks in real time, assembling a specific data (STOCK, 2018).  Manufacturing jobs are facing a risk of being automated, in this way, human beings will be affected by increased knowledge at work and task uncertainties (STOCK, 2018). Therefore, human resource management has been defined as an effective employment strategy and the development of a highly committed and qualified workforce to achieve the company's objectives (HECKLAU, 2016).

Anxiety
According to Spielberger (1966), the discriminatory use of the term anxiety refers to different constructions. The most commonly used denotation is a complex emotional reaction or state that varies in intensity and fluctuates over time due to stressful situations that affect an individual. While, for the American Psychiatric Society (2019), anxiety is a normal reaction to stress and can be beneficial in some situations, such as serving as a warning to identify a danger, however, it differs from anxiety disorders that involve fear or excessive anxiety.
The term "anxiety" also refers to individual differences in anxious tendency as a personality trait, people prone to anxiety as a personality trait are more willing to manifest anxious states than non-anxious people, while neurotic individuals have high traits of anxious personality and are more likely to respond to situations involving threats to self-esteem with greater increases in intensity of anxious state than people with lesser traces of anxiety (SPIELBERGER, 1966).
Anxiety is due to a concern, which is capable of ruining extensions of human life, be it the idea of the danger of falling into conformity with the ideals of success that are imposed by society and that as a result, says According to the United States Department of Health and Humanitarian Services (HHS, 2019), there are five major categories of anxiety disorders, namely: generalized anxiety disorder, obsessive-compulsive disorder, panic disorder, post-stress disorder traumatic, and social phobia (or social anxiety disorder). Generalized Anxious Disorder is characterized by chronic anxiety, exaggerated worry and tension, even though there is nothing to cause it. Obsessive-Compulsive Disorder is characterized by recurring unwanted thoughts, given as obsessions, and / or repetitive behaviors, called compulsives. Panic Disorder is characterized by repeated and unexpected episodes of intense fear, accompanied by physical symptoms that can include chest pain, heart palpitations, short breaths, dizziness, and abdominal pain (HHS, 2019). Also, according to HHS (2019), Posttraumatic Stress Disorder is characterized by the development after exposure to a frightening event or the result of a serious physical injury that occurred or was threatened. Finally, Social Phobia or Social Anxiety Disorder is characterized by enormous anxiety in daily social situations.
According to Linden (2007), the evidence that the work environment can play an important role in the development of anxiety problems and disorders has increased, and it is discussed as "bullying", "work stress", "burnout", or "overwork". In the results found by Halsam et. al (2005), it was identified that the uncontrollable workload contributed to anxiety. The post-traumatic stress disorder related to the work environment has been highlighted. According to Laposa et. al (2003), work-related anxiety disorders can manifest themselves in the form of phobia, social anxiety, or generalized anxiety and fears of insufficiency.
The lack of treatment, according to Halsam et. al (2005), has the potential to become a problem for employees who suffer from anxiety or depression, as they may experience symptoms of fatigue, or low concentration, which implies performance. According to Jones et. al (2015), organizations have emphasized the importance of improving employee psychological health, absenteeism, turnover and presenteeism, as mechanisms that affect the company's performance.
The relationship between anxiety and depression remains unknown, as shown by the study by Dealy et al. (1981), who investigate patients with symptoms of anxiety and depression, traditionally diagnosed based on their rates of depressive symptoms and anxiety symptoms. These authors found that there was no clear link between patients with anxiety and depressive disorders.

Depression
Depression, according to the American Psychological Association (2020), is the most common mental disorder, people with depression may experience a lack of interest and pleasure in daily activities, in addition to significant weight loss, insomnia or excessive sleep, lack of energy, lack of concentration, feelings of devaluation or excessive guilt and focused thoughts of death or suicide. According to Mousa (2016), in the United States, severe depression affects 14.8 million adults every year.
The difference, for Lewinsohn et al. (2000), between mood swings between degrees of significant and clinical depression, such as severe depression, and those that occur normally remains a problem. However, for the National Clinical Practice Guideline 90 (2010), the identification of severe depression is based not only on its severity, but also on the permanence, presence of other symptoms, and the functional and social severity.
Although the degrees of normal and clinically significant depression do not have clear, easy differences, the greater the severity of the depression, the greater the morbidity and adverse consequences. When considering other aspects, such as duration, stage of the disease and history of treatment, there are problems found in the classification of depression in categories (KESSING, 2007;LEWINSOHN, 2000).
Because of the complexity in identifying the severity of the depressive disorder, the literature recommends the use of a depression scale for the initial assessment. For this, there is a preference for the use of short scales with a "yes / no" answer format, such as the GDS with 30 items, or the Brief Depression Scale (BDS) with 11 items (BECK, 1998).

Review principles
In order to carry out this study, a systematic literature review was carried out using the following steps to exclude articles that are not compatible with the proposed theme. The scheme of the steps is illustrated in Table 1.

International Journal of Advanced Engineering Research and Science (IJAERS)
[  ii) Definition of keywords and their combinations The keywords defined were "industry 4.0", "anxiety", "depression", "quality of life", "HADS" and "WHOQOL", their combinations are detailed below.
iii) Defining the search criteria Research without time limit, works inserted as articles in the area of Psychology, Engineering, Social Science and Medicine. Containing in your title any of the keywords mentioned in step ii.

iv) Extraction of the searches found
The searches were extracted from the databases in the format ". ris ", treated using the JabRef program.

v) Duplication elimination
The elimination of duplicate articles was done by the JabRef tool.

vi) Definition and exclusion criteria for articles
After treating the results found for the removal of duplicates, the articles went through the refinement phase using the inclusion and exclusion criteria.

vii) Search for number of citations and impact factor
For the execution of Methodi Ordinatio, the number of citations of the articles and the impact factor of the journal in which the article was published are required.

Source: The authors (2020).
To ensure that all articles could be consistently accessed with fewer subjective opinions, the fundamental review principles for inclusion and exclusion criteria in step vi were defined in Table 2:

Systematic literature review method
In this study, the combination of the terms proposed in step ii generated the results in each selected database. 372 results were found using the combination and search criteria in the database Scopus, Web of Science, PubMed and MedLine, which are presented in Table 3 according to the keyword in the title, abstract and keywords, selecting only articles for filtering.

Source: The authors (2020).
After collecting the articles from the databases in the .ris format, the articles were treated using the Mendley® software to identify and remove duplicate articles, and by the JabRef® software to result in an electronic spreadsheet containing the following data: author, title, year of publication, journal, type of document and DOI / URL. An illustrative scheme of the execution of step vi is shown in Figure 2. Through this step, the number of articles found was filtered according to the inclusion and exclusion criteria previously defined, resulting in 102 articles for analysis at the end.

Data analysis
The data of the articles were analyzed quantitatively, through the frequency of publications in countries, the number of citations per article, the authors with the highest number of publications and the number of articles published per year. The qualitative analysis took place by forming clusters, in which the related articles were grouped and the content was analyzed, such as keywords, methodology and results.

IV.
RESULTS AND DISCUSSION Figure 3 shows the graphs used for the quantitative analysis of the articles found, such as graph A representing the number of articles per year, graph B with the number of citations per article, and graph C illustrating the number of articles by country.

International Journal of Advanced Engineering Research and Science (IJAERS)
[ Vol-7, Issue-12, Dec-2020]  https://dx.doi.org/10.22161/ijaers.712.39  ISSN: 2349-6495(P) | 2456-1908(O) www.ijaers.com Page | 289 Graph A showed that 52.9% of the articles published and present in the databases were published between 2018 and 2019, reinforcing the current status of industry 4.0, anxiety, depression and quality of life. Two works stood out for preceding the 21st century: Hallstrom (1984), which discusses depression in women in Sweden; and Lindgren (1996), which also addresses the depressive disorder, however it is a neuropsychological test for treatment, therefore, dealing with an article more focused on medicine.
In graph B, which shows the number of citations per article, it is possible to analyze that in the first years the number of articles provided a low number of citations, and over time, the number of citations increased. In The analysis of the number of articles by country, shows the countries of origin of the first authors of the articles collected. The United Kingdom, which stands out with 15 publications on the topics, is recognized for research in mental health and for being one of the major industrial hubs since the beginning of industrialization. the second country with the largest number of publications on the subject was the United States of America (USA) with 9 articles, and like the United Kingdom, the country presents a high technological technological advance, therefore, these two countries were expected among the first of publication number.
The top ten authors with the highest InOrdinatio publications are represented in Table 4. Through this table it is possible to identify that 70% of the articles with the highest InOrdinatio indexes were published in 2020 and 30% correspond to the 2018 publications.  (38,390,081). This work relates industry 4.0 with factors that influence the digitalization of commerce, with daily support and administrative tasks, in addition to supporting the decision-making process.
Among the ten articles with the highest InOrdinatio index, none were related to anxiety, depression or quality of life, but all are related to industry 4.0 and therefore published in journals with a high impact factor and a high
Through graphics D and E, shown in Figure 4, it is possible to analyze the impact factor of journals in relation to the average citations of the collected articles, and the articles that presented the InOrdinatio above the index average (7,320). When analyzing graph D, it was found that journals with an impact factor between 3302 and 3831 have higher average citations, than journals with a very high impact factor, or with zero impact factor.
The InOrdinatio index was used to prioritize the reading of articles with higher index values, as they have greater impact and relevance. From this, analyzing Graph E, the articles can be divided into above average of the InOrdinatio value and below the average value of the index. After analysis, it was identified that most articles are below the average value, therefore, a minority represent a higher value of citations and publications in journals with a high impact factor. Figure 5 groups the graph F that represents the clusters of the consolidated groups and the graphs G, H and I referring to the subcategory formed when analyzing the clusters.

Analysis of mental health cluster
In the mental health cluster, a subcategory stood out, many of the articles found were about treatments, among which we identified treatments for adults such as Castells et al.

V. CONCLUSION
Depressive and anxious disorders have been under discussion for decades, and remain a topic of debate in several areas, as well as industry. The human presence within the industry is facing an adaptation in the midst of automation, the collaborators who go through this transition, will need to be trained more and more to the new technologies, and will be subject to go through stressful factors, which can trigger anxiety disorders and depressive.
This article sought to work on the axes of industry 4.0, anxiety and depression, and quality of life, to analyze whether there is any connection between them in the literature, the new industrial revolution is in evidence in the academic area, and mental health has become a concern during the 21st century, in this way, the impact that industry 4.0 has on the mental health of its collaborators was not documented in scientific articles searched by the databases that compose this research, presenting a gap for future works.
In this literature review work, the researched databases, which still have a high academic value and reliability, do not include all the research that could address the themes. In addition to the databases, the restrictions and criteria defined may be a limitation, since all files that are not scientific articles have been removed.