Construction and validation of the Adult Stressors Inventory (ASI)

Introduction: A great deal of research has been conducted all over the world into stress and its impacts on the health of populations. Objective: To develop and validate an instrument for identification of the principal stressors and their magnitude in people who are subject to stress. Method: The instrument was constructed on the basis of analysis of 20 interviews conducted with 10 male and 10 female adults with stress according to the Perceived Stress Scale. A total of 46 statements were derived from this analysis, referring to stressful situations in different areas of life. Each statement is evaluated on a Likert response scale indicating the degree of impact and the respondent’s ability to deal with the stressor it describes. The instrument was validated with a non-probabilistic sample comprised 450 adults, aged from 18 to 65 years, 62.7% women and 37.3% men, who completed the instrument and also the Perceived Stress Scale, to enable criterion validation. Results: Exploratory factor analysis identified 42 valid items and grouped them into eight factors that explained 64.5% of total variance. These factors were financial stressors; working environment stressors; cognitive and behavioral stressors; family environment stressors; health status stressors; stressors related to conditions for relaxation; workload-related stressors; and social relationship stressors. Cronbach’s alpha for the instrument was 0.94. A relationship was observed between the newly- developed inventory and the Perceived Stress Scale, providing grounds for accepting the validation hypothesis. Conclusions: The results were psychometrically satisfactory and made possible provision of a new instrument for stress interventions, with advantages over other instruments.


Introduction
Stress was first conceptualized by Hans Selye, who described it as the general adaptation syndrome. 1 This syndrome consists of an organism's neuropsychophysiological response to events that could endanger its physical and psychological integrity and is characterized as a biological self-preservation mechanism. 2 Manifestation occurs in phases; an initial transitory stress, of low or high intensity, may progress to a state of deterioration that debilitates the immune system, at which point serious diseases may begin to emerge. [3][4][5][6][7] Several different studies have identified the presence of stress as a contributing factor in dermatological diseases 8 cardiovascular diseases, 9,10 and fibromyalgia, 11 and its role in mental disorders has also been demonstrated. 12 The stress response and the concept of homeostasis deal with the same phenomenon, i.e., the ways that organisms regulate and adjust in response to challenges.
However, the concept of homeostasis extends to that of allostasis, in which the response to stressor stimuli varies as a function of the degree of predictability, of the intensity, of the duration, and of the nature of the stressor stimulus. The response also involves subjective aspects such as the individual's expectations with relation to the challenges faced. These challenges activate homeostatic systems that initiate actions for regulation at more elevated levels of demand, to achieve a state known as allostasis. 13,14 Allostasis is a state of organic equilibrium that is set up in response to the level of environmental demands and the individual's assessment of them. This assessment is responsible for differences between different individuals responses to the same stressors.
The stimulus that elicits stress is called a "stressor" and is understood as an environmental event that significantly disturbs an individual's dynamics, provoking a state of alert and altering their physiological equilibrium. 3 A stressor can be defined as a potential threat that is unpredictable, uncontrollable, or unavoidable, challenging the individual to react and provoking physiological and behavioral responses. 4 The interindividual differences in responses to a stressor are manifest in the degree of impact it causes, which is determined by characteristics of the stimulus and by the organism's ability to deal with the situation. This, in turn, is the result of individual factors such as sex, age, temperament, and cognition, of the controllability of the stressor, and of social factors, such as social role and/or social support. [14][15][16] On the cognitive level, the response to the stressor is filtered according to the vulnerability of the person who will process the information and evaluate the situational aspects and to the stimuli presented as a result of it and which emotion will be elicited in response. The executive functions of the brain therefore play a moderating role in the response to stress. 17 The executive functions are primarily found in the prefrontal cortex and when a stimulus is perceived as stressful, these regions are activated and modulate the response to the stimulus by means of metacognitive processes. The lower the functional level of the executive functions, the stronger the response exhibited to the stressor will be, illustrating that metacognition plays an important role in regulation of the response to stress. 17 Metacognition refers to a person's knowledge and awareness of their own cognitive systems and the factors that can affect these systems. 18 Working from this concept, researchers have identified a positive correlation between metacognition and perception of stress, anxiety, and depression. 19  The description of this project will also be organized in two stages; the process of development of the inventory first, followed by the process for its validation.

Development
Since The free-floating reading content analysis technique was used to seek manifest and latent meanings in the information contained in the interview transcripts.
Taking a clinical-qualitative view, 33  and cognitive. Initially, the interviewees' utterances were classified by category and then, after they had been read and organized, the subcategories listed in  The participants invited to take part in the study were informed about the research objectives and its implications and procedures, and about any risks to which they could be exposed. This was achieved using a free and informed consent form. Those who agreed to take part signed two copies of the consent form and data collection was begun. First, a questionnaire was administered to collect sociodemographic data for categorization, then the PSS was administered, to identify the degree of perceived stress, and, finally, the ASI was administered.

Analysis
The results of the PSS were analyzed as recommended by its authors and sociodemographic data were analyzed using descriptive statistics to plot the profile of the sample investigated.
The internal consistency of the instrument (ASI) was analyzed by calculating Cronbach's alpha and by conducting exploratory factor analysis with varimax rotation and Kaiser normalization, according to psychometric principles. [37][38][39][40] These calculations were performed using the Statistical then excluded on the basis that their factor loadings and adequacy indicated that they did not fit the construct, since their factor loadings were below 0.4 ("My relatives' health has been worrying me") or because they did not fit the subject of the factor they had been assigned to ("My marriage/romantic relationship is not going well; Family members have died, which shook me" and "It is very difficult to deal with some clients at work").
Factor analysis was conducted once more with the remaining 42 items and this analysis identified eight factors with Eigenvalues greater than 1 that explained 64.5% of total variance. The rotational component matrix is shown in Table 2. Observing the content of the items that were grouped onto each factor, it was clear that they dealt with themes in common and these were used to name each of the factors, which became groups of items on the instrument (Table 3).
Cronbach's alpha for the entire 42-item instrument was 0.94 and none of the factors had an alpha value of less than 0.8 (Table 3). Table 4 lists the final set of items, with their respective factor loadings.
In order to test the hypothesis raised for criterion validation, it was necessary to identify those participants with the highest degree of stress according to the PSS and, since there are no normative data for this scale derived from the Brazilian population, the decision was taken to divide the sample into quartiles, which provided an intragroup criterion. It was assumed that the higher the quartile, the higher the person's perceived stress level. ANOVA was conducted for the variance between overall and factor results from the ASI against the PSS quartiles. The majority of factors exhibited significant differences with p ≤ 0.05 when paired against PSS quartiles. Only the second and third quartile pair, which represents a "middle zone," were related to fewer factors with significant differences. The means for total ASI score and by factors against each PSS quartile exhibited an ascending progression, in line with the trend of PSS results (Table 5).
It is believed that, since as the perception of stress increases, the perception of the intensity and magnitude of the stressors also increases, then the ASI has the sensitivity to measure these stressors, which confirms the validation hypothesis.

Discussion
The process of validation of a psychological instrument starts with formulation of detailed definitions of the trait or construct that it is intended to measure, which are derived from the theory on the subject, from earlier research, or from systematic observation and analysis of the behavioral domain that it belongs to. 38 Thus, the process to develop the Adult Stressors Inventory (ASI) is derived not only from the psychological theory that defines the construct of "stressors," 1,3,4 but also from a systematic process of observation and analysis of the behavioral domain that encompasses it.
The statements that comprise the ASI items originated from analysis of the content 35 of interviews with adults who were exhibiting stress, which revealed the occurrence of stressors in five areas of life that proved to be stress-provoking: finances, work, social relationships, family, and health. Additionally, the analysis revealed cognitive factors that appear to interfere with generation and maintenance of stress.
The areas identified in the interviews can be referred to as stress generation domains and are in line with what is found in the literature on stress and stressors. [5][6][7]42 When formulating the items for the ASI, care was taken to ensure that they portrayed daily problems that could refer to "dangers" to the life of the person to whom the instrument is being administered and constituted stressors as conceptualized in the literature, 1,3,4,42 comprising life events, chronic demands, and day-to-day irritations. 42 Additionally, the literature identifies internal stressors as types of cognition 17,19,21,43 that predispose people to development of a state of stress. A sixth domain was therefore formulated, initially entitled "cognition," which contained statements referring to thoughts and behaviors that predispose a person to stress.    provoke. It is interesting to observe that this factor was not part of the initial construct underlying the inventory, its ability to identify the area provoking stress, the ASI also appears to be capable of identifying the magnitude of each area's contribution to stress. It was therefore observed that basic properties such as validity and reliability or trustworthiness are fulfilled by the ASI. 44 These data indicate that the ASI fulfills the criterion of evaluating the intensity of the stress-inducing stimulus. This demonstrates a positive improvement over the Holmes scale, since it appears that the ASI is adequately evaluating variability of perception of stress-inducing stimuli.

With regard to comparisons between ASI and other
instruments for assessment of stress or stressors, the ASI offers advantages over other available instruments, since it covers eight domains of stress generation with good psychometric properties. For example, instruments have been developed to evaluate stress in nursing students, 53 in teachers in the context of employment, 30 and in production-line workers, 28 among others, but all of these address specific scenarios and do not extend to a broader spectrum of stressors.
Two options for evaluation of a broader spectrum of stressful events do exist. The Impact of Event Scale has been translated and adapted for Brazil 54

Conclusions
The Adult Stressors Inventory (ASI), demonstrated adequate internal consistency and factor analysis revealed that it was coherent with the initial constructs, which appears to denote that the newly-developed instrument has adequate construct validity and discriminatory validity.
It was observed that the ASI has good psychometric capacities when compared with the results of the PSS for the same sample. The sample employed covered the many different variables that can interfere in the stress process, proving to be consistent with the literature. One interesting point observed during validation of the instrument is the clear relationship between the factors identified by factor analysis and what is stated in the Brazilian and international literature on stress, and also with the original construct.
One limitation of this study is related to analysis of data by sex and age group, which would require a sample that had been planned in advance and was more balanced in this respect.
It would be interesting to expand the sample in order to test whether the instrument discriminates by the variables sex, age, marital status, and profession. Such an analysis could show whether the ASI scores exhibit differences associated with social and demographic factors and could be used to derive normative data for interpretation of results.
This study's primary contribution lies in the possibility of making an instrument available for objectively understanding stressors that could be responsible for generating and maintaining stress. Understanding the source of stress provides a basis for development and application of strategies focused on its treatment.