PREDICTORS OF PSYCHOLOGICAL STRESS OCCURRING AFTER THE FIRST WAVE OF THE COVID-19: A CROSS-SECTIONAL STUDY IN POLAND

The article presents the results of research aimed to identify the predictors of psychological distress among Poles seven months after the occurrence of the first case of COVID-19. In order to gather the research material, the CAWI on-line survey method was applied and carried out within the framework of the Ariadna Research Panel on the sample of 1079 Poles aged 15 and over. The results of the conducted research indicate that Polish society experienced psychological distress as a result of the first wave of the pandemic. According to the Kessler Psychological Distress Scale (K10), no mental disorders were observed among 36% of Poles, mild mental disorders were observed among 23% of respondents, average levels of disorders were observed among 18% of respondents, whereas high levels of disorders were observed among 23% of respondents. A hierarchical linear regression analysis was used to identify the predictors of psychological distress. In the first stage, socio-demographic variables explained 20% of the distress variance. In the second stage, the variables measuring social nuisances of the pandemic were introduced, which increased the percentage of the explained stress variance to 33%. In the third stage, the introduced psychological variables increased the percentage of the explained variance to 73%. The main factor which increased stress levels was neuroticism. The conducted analyses have shown that the lack of social, economic and psychological capital significantly increases the susceptibility to distress when a threat to life and health lasts for a prolonged period of time.


Introduction
The COVID-19 pandemic has become a global trauma, leading to a deterioration of mental health of millions of people all over the world (Demertzis, Eyerman, 2020;Johnson et. al., 2020). The pandemic has triggered an array of emotional, physical, and economic issues.
The conducted comparative analyses of mental health indices, measured before and during the pandemic, indicate the deterioration of mental health in many countries (Anexity and Depression 2020; Gray et al., 2020;Pierce et al., 2020). Apart from a threat to life and health among the society, nuisances connected with the quarantine, social isolation, deprivation of needs, the loss of job and financial resources, new stressors have emerged during the development of the pandemic. The unpredictability of the nature of the virus creates circumstances of ongoing stress, which can increase the risk of people developing psychological disorders (Zandifar, Badrfam 2020).
The pandemic of COVID-19 is severely affecting mental health worldwide.
Considerable knowledge about the influence of the pandemic on mental health has already been acquired (Arora et al., 2020;Salari et al., 2020). Risk factors having influence on the level of experienced psychological distress have been studied to a lesser extent. Numerous research conducted on representative samples indicates that there are individual and group differences in the susceptibility to stress related to the pandemic.
On the basis of the conducted analyses, three groups of predictors having influence on the level of stress experienced during the pandemic have been distinguished. The first category includes socio-demographic variables, such as sex, age, marital status, financial standing, education level and social connections (Li et al., 2020;Flesia et al., 2020;Qiu et al., 2020;Zhou et al., 2020;Duan et al., 2020). The second category of risk factors includes social effects of the pandemic, such as a decrease in social security, the sense of uncertainty, the sense of deprivation and a change in one's lifestyle (Satici et al., 2020;Elis et al., 2020, Shanahan et al., 2020. The third category of variables includes individual psychological traits, such as neuroticism, stability, optimism and internalisation of control (Flesia et al., 2020;Ferreira et al., 2020;Nikčević et al., 202, Taylor 2019).
The studies into the predictors of stress conducted to date rarely consider the question of influence of factors of social and economic nature. Therefore, in the following stage, an attempt was taken to verify whether secondary effects of the pandemic, such as a change in one's lifestyle, deprivation of needs and limitations of social functioning which results from the pandemic will be significant, similarly to demographic or psychological factors.
The main aim of this paper is to demonstrate the predictors of stress and their impact on mental health after the first wave of the pandemic, illustrated by the example of Poland. In the seventh month after the rise of the COVID-19 pandemic, it was possible to estimate social costs of lockdown.
The study of stress and its predictors fits into findings on psychological effects of disasters (Osofsky et al., 2015;Rhodes et al.,2010). Thanks to the acquired knowledge, it will be possible to get to know better the functioning of the society in the situation of a crisis, and develop solutions which could allow for helping people with their return to a good mental wellbeing.
On the basis of the COR stress theory (Hobfoll, 1988(Hobfoll, , 1989(Hobfoll, , 1991, a hypothesis that the COVID-19 has lead the Polish society to the loss of psychological and social resources which resulted in psychological distress may be put forward. The higher the sense of the loss of resources among individuals, the higher the level of stress.

2.1.Participants and procedure
The study was conducted on a representative nationwide Polish sample (N = 1,079; 554 women; age range = 15 to 94, M = 42.4, SD = 16.7). The participants were recruited using the Ariadna Polish on-line panel (CAWI). Participants were rewarded for their participation with points collected via their panel membership, the points being exchangeable for rewards in a pool of several hundred products offered by the panel organizers. All participants provided their informed consent.
This method was used due to social isolation, which is taking place during the pandemic.
Nonetheless, as shown by the results of research, the questions related to the measurement of mental health indicators conducted with the use of an on-line survey are as accurate as standard paper-and-pencil tests (Brock et al., Coles et al., 2007).
The studies were carried out between the 26 th and the 30 th of October 2020. On the day of the commencement of the research, there were 1584 cases of COVID-19 in Poland, whereas on the 30 th of September there were 1552 cases. The research was conducted a day before the second wave of the pandemic, as from October the number of incidences increased dramatically and by the end of the month there were over 22 000 cases. Therefore, the research was conducted in the circumstances of a relative stabilisation of the number of incidences after the summer break. It may be assumed that it was a perfect moment to capture the consequences of the pandemic after the first wave.

Demographic characteristics
The research form included questions regarding the following demographic factors: gender, age, education, socio-economic status, marital status and having children, place of residence, religiosity (Table 1). Social capital is a significant factor which is of a strategic importance in the situation of stress. It provides an individual with the necessary social support (Caplan 1974;Cassel 1976).
There is evidence of its positive impact on the psychological well-being of the society (Putnam 2001). In the measurement of social capital, five items were used for asking about the possessed support, with the use of a nominal "yes, no, I don't know" scale. The distribution of the social capital in the researched group is presented below. Scores range from 0 to 5. The average social capital index was 3.4, (SD=1,6).  The gathered responses indicate that 45% of respondents resigned from a tourist trip, 39% resigned from social and family meetings, 56% of respondents resigned from their participation in cultural events and 32% of respondents resigned from religious services.
Scores ranged from 0 to 4. The higher the score, the higher the level of life changes. The average on the scale was 1.7, SD=1.2.

Deprivation of needs index
Apart from a change in social habits, the pandemic has significantly influenced the possibility of satisfying different basic and higher-level needs. The closing-up of shops, shopping malls, fitness centres, workplaces and national borders has resulted in serious restrictions as regards satisfying one's needs. Inability to use social infrastructure and limitations in spending one's free time, entertainment and participation in cultural events may generate frustration and have negative impact on mental health of Poles.
The deprivation of needs index has been prepared on the basis of answers pertaining to the impact of the COVID-19 pandemic on various aspects of social functioning. The instrument measuring the deprivation of needs includes 8 questions in which respondents marked whether the pandemic had a positive, negative or no impact on a particular aspect of living. Detailed distribution of answers shown in percentage is presented in Table 3. The deprivation of needs index consists of answers indicating deterioration of possibilities to satisfy one's needs, and its score ranges from 0 to 8. The average on the scale was 2.1, SD=2.1.

Mindset changes index
The pandemic, apart from a decrease in the sense of social security, has lead to the loss of control over one's life and events occurring in it. The table shows distribution of answers, which depict the cognitive effects of COVID-19. The loss of psychological resources index was constructed by means of summing up the answers indicating a decrease in self-confidence in the fields presented in the table. Scores ranged from 0 to 6. The higher the score, the bigger the loss of psychological resources. The average on the scale was 1.7, SD=1.6. 2.3.6. The sense of threat of becoming infected with COVID-19 The sense of threat of becoming infected with COVID-19 may be a significant factor connected with the creation of stress in the circumstances of the pandemic. By means of an open-ended question, the respondents were asked to estimate the probability of becoming infected with coronavirus on the scale from 0 to 100. Average chances of becoming infected have been estimated to 40.9%, SD=25.8.

The level of interest in the information on the pandemic
Numerous studies indicate that the symptoms of stress intensify together with an increased interest in the pandemic. Therefore, this variable was measured as well. The scale used to measure the level of interest in the pandemic consists of 4 points. The score ranges from 0 to 4. The responses covered the range from "I'm not interested at all" to "I'm very interested".
Higher values indicate a higher interest. The average on the scale was 2.9, SD=0.7. Respondents were asked to indicate the degree to which they agree with each item on a 5-point Likert-type scale ranging from 1 (definitely not) to 5 (definitely yes). Scores range from 9 to 45. In the current study, the ( The response for each item was recorded according to a 5-point Likert scale ranging from 1 (definitely not) to 5 (definitely yes). The overall score of fear (ranging from 10 to 50) was obtained by adding up each item score. The higher the overall score, the greater the fear of COVID-19. Cronbach α = 0.93. The average fear on COVID-19 Scale was 23,7, SD=9.

Neuroticism
Neuroticism is deemed a crucial stress factor (Eysenck 1990). Neuroticism is a personality trait, which is characterised by a tendency to the occurrence of negative emotions, such as depression, anxiety or anger. Individuals with high neuroticism scores perceive the world as threatening, they are quickly distressed, and it is difficult for them to cope with stressful situations (Cohen et al., 2012). The studies into fear of COVID-19 have shown that neuroticism as one of elements of the Big Five has a negative impact on mental health during the COVID-19 pandemic (Nikčević et al., 2020).
The scale used to measure neuroticism was constructed according to the model of the Neuroticism Scale of the Eysenck Personality Questionnaire-Revised (EPQ-R) (Eysenck & Eysenck, 1975). It consists of 13 items. The response for each item was recorded according to a 5-point Likert scale ranging from 1 (definitely not) to 5 (definitely yes). Scores on this scale ranged from 13 to 65, with higher scores indicating higher levels of neuroticism. Coefficient alpha in the present study was 0.87. The average (EPQ-R) was 38.0, SD=8.

Psychological Distress
In order to measure the dependent variable, the Kessler Psychological Distress Scale (K10) which measures the symptoms of anxiety and depression in the society was used (Kessler et al., 2003). The scale consists of 10 items and its Cronbach α = 0.948. The response for each item was recorded according to a 5-point Likert scale ranging from 1 (All of the time) to 5 (None of the time).
The minimum value on the scale was 10, whereas the maximum value was 50. The average value for the researched sample was M=22.9, SD=8.1. According to the scale's diagnostic criteria (Kessler et al., 2003), the lack of mental disorders (up to 10 points) was observed among 36% of respondents. Mild disorders (20-24 points) were observed among 23% of respondents. An average level of disorders (25-30 points) was observed among 18% of respondents. High levels of disorders (more than 30 points) was observed among 23% of Poles. The correlation between the scale of stress and the predictors taken into account in the analysis are presented in Table 6.  Hierarchical regression analysis was used to study the relationship between sociodemographic, psychological, social effect variables and the level of stress. In the first stage, socio-demographic variables were introduced, in the second stage, the variables measuring negative effects of lockdown and the level of interest in the information on the pandemic were applied, and in the third stage, the psychological variables were introduced to the model.
The results of the hierarchical regression analysis indicate the fact that demographic variables explain 20% of stress variance. Higher levels of stress were experienced by females, young people, lonely people, people whose father's education was lower, people deprived of social support and assessing their financial standing as worse. Introducing

Discussion
The aim of this paper is to determine risk factors increasing the levels of experienced stress after the first wave of the pandemic. It has been assumed that the level of stress will be determined by the loss of financial, social and psychological resources (Hobfoll 1991).
The results of linear regression analysis partially confirm the assumed hypothesis. By means of analyses, it has been shown that three factors determine the level of stress. Sociodemographic variables explain only 20% of the dependent variable variance. Higher levels of stress were observed among females, young people, single people, people whose father's education was lower and people who were devoid of social capital and evaluated their financial standing as worse.
The predictors distinguished in the first regression model indicate that the highest level of distress could be observed among the youngest age groups. These results are consistent with the findings of researchers from many different countries (Branquinho et. al., 2020;Gray et. al., 2020). Meta-analyses also indicate a worse mental condition of young people in the time of the COVID-19 pandemic (de Miranda, et. al., 2020). Higher levels of stress may be explained by the fact that, first of all, just before the pandemic youth had a worse mental condition than adults (Putnam 2000;Twenge 2017). The pandemic might have intensified these trends.
Secondly, among younger age groups, peer relations are the main need (Smetana et. al., 2006).
Quarantine and social distancing have resulted in a deprivation of this need, at the same time deepening the distress (Brooks et al., 2020). The analyses have analogically shown higher levels of stress among females, similarly to other studies (Luo et al., 2020). The influence of gender may be explained by the fact that emotional stability is lower in women and increases in later years (Marsh et al., 2012). A higher distress was observed among people with lower social capital and lonely people, which may indicate the crucial role of social support in the time of the threat of the pandemic. Married people and people who have others willing to help cope with the pandemic better, which is indicated by many other studies (Luo et al., 2020).
Respondents in a worse financial situation had a worse mental health. This may mean that the lack of financial resources lowers adaptive capabilities. Together with the decrease of the respondent's father's education, distress increases, which may confirm the impact of cultural resources on mental health. The respondent's father's education may be a better index of cultural capital due to the fact that higher education has become popularised and suffers inflation (Wilson 1999;Colins 2019). This may mean that higher social standing prevents individuals from experiencing stress.
In the second model of regression analysis, the indices aimed at indicating secondary effects of the pandemic, such as limitations of social activities or limitations in satisfying one's needs were introduced. It has been shown that the level of explained variance of the distress scale has increased by more than 10%. Variables, such as father's education, marital status and social capital turned out to be statistically relevant. Moreover, it was observed that people indicating a higher probability of becoming infected with coronavirus and experiencing financial losses due to the pandemic had higher levels of stress. This may confirm the theory of the impact of the loss of resources on experienced stress (Hobfoll 1989  had the strongest force of impact. This may mean that neuroticism is a moderator of stress and acts as an intermediary in the perception of reality. In the situation of threat of the pandemic, it increases the sense of threat and by the same means it significantly increases the level of psychological distress, which is indicated by other studies (Kroencke et al., 2020;Caci et. al., 2020;Nikčević et. al., 2020).

Conclusions
The results of research conducted after the first wave of the COVID-19 pandemic (seven months after the occurrence of COVID-19 in Poland) indicate that only 36% of Poles have not experienced psychological distress. The respondents experienced anxiety, irritability, fatigue and gloom most often. The pandemic and threat posed by it which last for a long time have led to a bad mental condition.
The main factor which had impact on psychological distress was neuroticism.
Emotionally unstable individuals, people with higher levels of fear and depression had a difficulty coping with the threat and the situation of uncertainty in the time of the pandemic.
Apart from neuroticism, socio-demographic variables and experienced financial losses had impact on distress. The results of research indicate that psychological, social and financial resources may protect individuals from the COVID-19-related distress. Therefore, during and after the pandemic, the main focus should be providing people who are lonely, lost their jobs and income due to the pandemic and those who present neurotic disorders with support and care.

Limitations
The presented research has certain limitations. First of all, research was conducted during a relative decrease in the number of COVID-19 incidences, after the summer break, during which the society could have forgotten about the threat, which as a result could influence the obtained results. Secondly, the on-line survey (CAWI) has an over-representation of respondents with education higher than Poles in general, in spite of all the attempts to provide a representative sample. Elderly and poor people as well as those with no Internet connection could have been passed over in the research sample. Thirdly, the study was of a cross-cutting nature. Therefore, it is difficult to evaluate to what extent the COVID-19 influenced the mental health of Polish sociey.