Social Work Environment and Mental Health

Transcription

1 A C U L T Y O F H E A L T H A N D M E D I C A L S C I E N C E S U N I V E R S I T Y O F C O P E N H A G E N Social Work Environment and Mental Health An epidemiological study of interpersonal work environment factors as predictors of psychotropic treatment Ida Elisabeth Huitfeldt Madsen PhD thesis

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3 Social Work Environment and Mental Health An epidemiological study of interpersonal work environment factors as predictors of psychotropic treatment Ida Elisabeth Huitfeldt Madsen PhD thesis Faculty of Health and Medical Sciences University of Copenhagen and National Research Centre for the Working Environment 2012

4 Social Work Environment and Mental Health An epidemiological study of interpersonal work environment factors as predictors of psychotropic treatment Ida Elisabeth Huitfeldt Madsen PhD thesis Submitted June 2012 Defended September 2012 ISBN Academic Advisors Professor Reiner Rugulies Professor Finn Diderichsen National Research Centre for the Working Environment, University of Copenhagen, Dept. of Public Health University of Copenhagen, Dept. of Public Health Assessment Committee Professor Jens Peter Bonde Professor Tarani Chandola Dr. Maria Melchior University of Copenhagen, Denmark (Chair) University of Manchester, United Kingdom National Institutes of Health and Medical Research (INSERM), France

5 PREFACE This thesis concludes the PhD project Social Work Environment Factors and Psychopharmateuticals which was conducted at the National Research Centre for the Working Environment in Copenhagen during July June The project was funded by the Danish Work Environment Research Fund (grant ) and examined whether social factors in the workplace are associated with risk of developing common mental disorder, as indicated by treatment with psychotropic medications (antidepressants, anxiolytics, hypnotics). The project was approved by the Danish data protection agency (reference number ). Several individuals have been instrumental in conducting this PhD and thus deserve my gratitude. First, I would like to thank my supervisors Reiner Rugulies and Finn Diderichsen for their invaluable and insightful guidance and support throughout the project. Second, I wish to thank my co-authors on the journal articles for their constructive criticism, and especially Linda L Magnusson Hanson who was in charge of the Swedish analyses. Third, I would like to thank my colleagues at the National Research Centre for the Working Environment, in particular the members of the PIVA research group; amongst them, a special thanks goes to Maj Britt Dahl Nielsen for her ever supportive companionship in our office. Finally, the project was based on existing data that were collected for previous work environment studies and I would like to thank all researchers and respondents who helped make these data available through their work or participation in the studies PUMA, COPSOQ, DWECS, DHCWC-2004, and SLOSH. Ida E. H. Madsen, June 29, 2012

6 1. INTRODUCTION COMMON MENTAL DISORDER CAUSES OF COMMON MENTAL DISORDERS WORK ENVIRONMENT AND COMMON MENTAL DISORDER SOCIAL WORK ENVIRONMENT FACTORS HYPOTHESES METHODS DATA SOURCES OPERATIONALIZATIONS OF EXPOSURES OPERATIONALIZATION OF OUTCOME COVARIATES STUDY POPULATIONS STATISTICAL ANALYSES STATISTICAL MODELLING CONFOUNDER SELECTION SUMMARY OF FINDINGS ARTICLE 1: WORK-RELATED VIOLENCE AND PSYCHOTROPICS ARTICLE 2: PERSON-RELATED WORK AND PSYCHOTROPICS ARTICLE 3: ELDERCARE WORK AND ANTIDEPRESSANT TREATMENT ARTICLE 4: WORK ENVIRONMENT AND ANTIDEPRESSANTS IN DENMARK AND SWEDEN ARTICLE 5: EMOTIONAL DEMANDS AND ANTIDEPRESSANTS: BUFFERING BY LEADERSHIP DISCUSSION METHODOLOGICAL DISCUSSION RELATIONS TO PREVIOUS FINDINGS PRACTICAL IMPLICATIONS CONCLUSION LIST OF APPENDICES 7. LIST OF ENCLOSURES Madsen 2012 Social Work Environment and Mental Health

7 1. INTRODUCTION Common mental disorders are prevalent and incur substantial human and societal costs (1;2). These disorders are thought to result from an interplay of biological, psychological and social factors (3-7), and research shows that common mental disorders may be predicted by work environment exposures including high psychological demands and low social support (8-11). Knowledge is scarce (10), however, concerning the role of work environment factors outside the established theories of Job Strain (12) and Effort Reward Imbalance (13). This thesis examines the associations between social work environment factors and psychotropic treatment, as an indicator of clinically significant common mental disorder. The thesis starts with an overview of the existing knowledge in the field, including the epidemiology and costs of common mental disorders, the causes of common mental disorders, and a presentation of the examined work environment exposures. This introduction ends by stating the specific hypotheses tested in the thesis. Following the introduction is a review of the methodologies applied in the thesis, including the data sources, operationalizations of key constructs, study populations, and the statistical analyses. After this methodological presentation, the results are summarized. The results encompass those of five journal articles, three of which are published (articles 1-3). Also, a supplementary analysis is included of the hypotheses examined in article 2 as this article was the first written and it was based on a subsample of data which were available early in the project. The journal articles are included as appendices 1-5. The results are followed by a discussion of key methodological concerns and a relation of the findings to previous literature. This discussion is concluded by an outline of the practical implications of the results. Finally, the thesis ends with an overall conclusion to the findings. Madsen 2012 Social Work Environment and Mental Health 1

8 1.1. COMMON MENTAL DISORDER In this thesis, the term Common Mental Disorder refers collectively to depressive and anxiety disorders, and clinically significant insomnia. These conditions are interrelated as they have high comorbidity (5-7;14;15) and insomnia may be a symptom of depression or anxiety (16;17). The symptoms also overlap between depressive and anxiety disorders as anxiety symptoms are prevalent in individuals with depression (5;6). The main symptom difference between these disorders is that individuals with anxiety disorder rarely experience certain depressive symptoms, particularly anhedonia and cognitive and motor retardation (5;6). Furthermore, there may be a causal effect of insomnia and anxiety disorders on depression (3-5;7;14). Common mental disorders are prevalent and incur high human and societal costs. European data estimate 12-month prevalences of 9% for depressive disorders and 12% for anxiety disorders (1), and a review found primary insomnia prevalences of 2%-4% (16). Common mental disorders are associated with substantially reduced quality of life (2;7) and The World Bank estimates that unipolar depressive disorders are the third greatest cause of disease burden in high-income countries and the greatest world-wide cause of years lived with disability (18;19). Societal costs of common mental disorders include not only treatment expenses, but also productivity loss (2;7); the European Study on Epidemiology of Mental Disorders (ESEMed) (2) found that individuals with major depression lost on average 9% of work days during the past month. For anxiety disorders, the most disabling subtypes were panic disorder, specific phobia and posttraumatic stress syndrome each associated with 11% lost work days (2). Furthermore, common mental disorders are associated with exclusion from the labour market (20;21) and they are the most frequent reason for disability retirement in Denmark (22). Madsen 2012 Social Work Environment and Mental Health 2

9 1.2. CAUSES OF COMMON MENTAL DISORDERS Common mental disorders are multifactorially caused in an interplay of biological, social and psychological factors (3-7). The psychological theories of depression include psychodynamic, behavioural and cognitive perspectives (23). Representing the psychodynamic view, Freudian theory suggests that depression may result from unprocessed grief when an individual loses an object (e.g. person, group, ideal) with which they identify and feel ambivalent towards (23). Other psychodynamic theorists propose that depression stems from a loss of self-esteem when ideals cannot be fulfilled, or that depression is aggression turned against the self due to anger expression issues (23). Seligman found, based on animal experimentation, that repeated exposure to uncontrollable circumstances may cause a state of learned helplessness and eventually depression (23). Behavioural theories build on this idea and propose that depression results from lacking adaptive social behaviours (e.g. assertiveness, positive response to challenge, seeking affection and caretaking) caused by a loss of social reinforcement (23). According to the cognitive perspective, early experiences may cause global negative assumptions (schemata) and schemata involving all-or-nothing thinking are a central cause of depression (23). Anxiety disorders, according to Freud, stem from intrapsychic conflict between instinctual drives, super-ego prohibitions and external reality demands (24). Anxiety signals the ego to mobilize defence mechanisms (e.g. repression) to restore intrapsychic balance (24). Behavioural theories, on the other hand, suggest that anxiety is the conditioned response to a specific environmental stimulus that becomes generalised, or that anxiety may be learned from social modelling of anxious behaviours (24). The cognitive theories of anxiety are disorder-specific; as an example, generalised anxiety disorder (GAD) is thought to stem from insecure and anxious early attachment relations, or cognitive schemas of the world as a dangerous place (24). In GAD, worrying becomes a strategy to avoid intense negative affect, and worrying about unlikely future Madsen 2012 Social Work Environment and Mental Health 3

10 threat removes the need to deal with present and more realistic threats and conflicts (24). Also, a degree of magical thinking occurs, and the individual may find that worrying about future threats helps prevent them (24). Despite the distinct psychological theories of depressive and anxiety disorders, some have argued that similar factors may affect common mental disorders collectively (5-7;14). Studies have indicated that depressive and anxiety disorders have shared risk factors, possibly indicating common underlying biological and psychological vulnerabilities (5;7;14). Following this perspective, common mental disorders develop in a stress-diathesis framework and stressful situations may trigger existing vulnerabilities (3-7). Vulnerability factors may be genetic, biological, psychological or social (3-7), and the stressful situations may be singular events (e.g. assault) or ongoing difficulties (e.g. marital discord) (3-7). Genetics may affect vulnerability to environmental stressors, and so might early environmental factors such as the relationship with caregivers and parenting quality (5;6). In addition to acting as vulnerability factors, these early influences may moderate genetic effects (5;6). Psychological vulnerabilities to common mental disorder include neuroticism, low self-worth and low sense of control over external events (5;6). Effects of stressful situations may furthermore be influenced by attributions about their causes as internal or external, global or specific, and stable or unstable (5;6;25). Not only early life social factors such as the quality of care and parenting (5;6), but also social factors in adulthood have shown important for the risk of common mental disorders. Marriage has been found protective for common mental disorder (6;26), and problematic social relations such as low social support, relationship difficulties, marital discord, lack of an intimate confidant and discontentment with partner status have been associated with increased risk (3;4;6;27). A causal effect of interpersonal factors on common mental disorders is plausible because negative interpersonal interactions and social rejection may lower selfesteem and self-worth (28;29), which may in turn increase risk of disorder (3;4;14;29;30). These factors have been studied extensively in the private life domain (29), but less so within a workplace context. Madsen 2012 Social Work Environment and Mental Health 4

11 1.3. WORK ENVIRONMENT AND COMMON MENTAL DISORDER Research on the relations between the working environment and common mental disorder has mainly focused on the theoretical models of Job Strain (12) and Effort-Reward-Imbalance (13). According to a systematic literature review from 2006 (8), robust evidence exists that high demands and low decision latitude, and high efforts and low rewards are prospective risk factors for common mental disorders. This review, however, did not distinguish between different types of common mental disorder (10), and the clinical significance of the outcome-measures, which were largely self-reported, was uncertain (9). Consequently, three systematic reviews were subsequently published in 2008 by Bonde (9), Netterstrøm et al. (10) and Siegrist (11), focusing on the effects of the psychosocial work environment on depression. All three reviews found evidence of a prospective association between self-reported high demands and low social support at work and depression, whereas the findings for control at work were less consistent. The reviews did, however, point to several limitations of the literature. Bonde and Siegrist pointed out that most studies had examined self-reported exposures that may have been affected by baseline mental health (9;11). Studies using independent measures of exposure and outcome were lacking, and self-report on both factors could cause common method bias (9). Also, according to Bonde, studies examining the risk of clinically significant depression were lacking, as many studies used an outcome that did not necessarily correspond to a clinical diagnosis (9). Based on these limitations, Bonde concluded that there was no sound evidence for a causal effect of work environment on depression (9). The Netterstrøm review found indications of publication bias in the published findings and stated a need for further research with more precise assessment of exposure duration and intensity (10). Furthermore, the review found a need for more studies examining common mental disorders other than depression using a clinically significant outcome measure (10). Finally, the authors pointed to a lack of studies examining exposures outside the established job strain and effort reward imbalance models (10). Madsen 2012 Social Work Environment and Mental Health 5

12 1.4. SOCIAL WORK ENVIRONMENT FACTORS The focus of this thesis is on the effects of social, i.e. interpersonal, work environment factors on common mental disorder. More specifically, the work environment factors examined are: violence at work, personrelated work, emotional demands and emotional labour. The following sections present these exposures, and argue why they might be related to the development of common mental disorder VIOLENCE AT WORK The World Health Organization defines violence as The intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, that either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment or deprivation. (31, p. 5). One of the exposures examined in this thesis is work-related violence, i.e. violence that occurs in the work-place and is directed toward staff. Work-related violence has been associated with self-reported mental health outcomes such as emotional exhaustion (32), sleep problems (33), anxiety (34), and depression (35). Research shows that workrelated violence is associated with feelings of helplessness (36), and a causal effect on common mental disorders is therefore plausible, as helplessness may be causally related to these disorders (25). There is a paucity of evidence, however, linking work-related violence with clinically significant common mental disorder. Also, most existing studies have been occupation-specific (32-35;37;38), raising questions regarding the generalizability of the findings. One large register-based study (39) showed that employees in occupations with high levels of work-related violence were at increased risk of hospitalization with depression or anxiety, but the lacking individual level exposure measures restricted causal inference due to the ecological fallacy (40). Madsen 2012 Social Work Environment and Mental Health 6

13 PERSON-RELATED WORK Person-related work is an umbrella term for jobs that require face-to-face or voice-to-voice interactions with individuals not employed at the work-place (clients) (41). This term covers both customer service work, and the occupations sometimes referred to as human service work, e.g. nursing, care work, teaching and social work. Human service work, in this thesis, is work in human service organizations. The term human service organization was coined by Hasenfeld & English (42), and names organizations where the main purpose of the organization is to increase or maintain the functioning and well-being of the client (42). This could be in a hospital, where the purpose is to make ill patients healthy, or in a school, where the aim is to increase the pupils educational level. Human service work has been argued to be particularly emotionally demanding because it involves confrontation with the clients problems and suffering (43) and because the interactions with clients require empathy and sensitivity to their emotions (41). Also, the relationship between human service workers and their clients may become imbalanced if the worker does not receive the rewards they expect for their work, in terms of for instance gratitude, or that the client improves or attempts to do so (44). Some researchers have even argued that imbalance is a fundamental premise in the relationship between human service workers and clients as the employee provides emotional resources that the client receives as illustrated by the terminology of caregiver and care-recipient (45). Because reciprocity in interpersonal relationships is pivotal to human well-being, such imbalance is thought to drain the employee s emotional resources and lead to adverse emotional consequences (13;44). Jenkins & Maslach (46) argue that human service occupations such as health care, educational and social work place high interpersonal demands on the employees by placing them in a helping role or requiring that they deal with people in stressful situations (46). They further argue that customer service work involves intermediate interpersonal demands, as they are associated with high social requirements but lower levels of social-emotional stress in the daily work routine (46). Madsen 2012 Social Work Environment and Mental Health 7

14 Human service work has been related to poor mental health outcomes such as suicide (47) and hospitalization with depression and anxiety (48-50), and the potential mental health effects of human service work was the focus of early burnout research (51). Burnout is a condition characterized by exhaustion, cynicism and inefficacy (51). Burnout is correlated with both depression and anxiety, but whereas depression affects all life-domains, burnout is specific to the work context (51). The clinical diagnosis closest resembling the phenomenon of burnout is neurasthenia (51). Burnout is thought to result from chronic emotional and interpersonal job stressors (51) and some research suggests that burnout may be a mediating factor in the relationship between work environment and depression (52) POTENTIAL MEDIATORS BETWEEN PERSON-RELATED WORK AND COMMON MENTAL DISORDER Person-related work may affect the risk of common mental disorder through work environment factors disproportionately prevalent within these occupations, namely the emotional demands of the work, the emotional labour, and the exposure to work-related violence. Regarding violence, a potential effect on common mental disorder has been argued in a previous section (see section 1.4.1), and it is known that violence is more prevalent in person-related work (39). The following section of this thesis therefore focuses on emotional demands and demands for hiding emotions, and why they might mediate an effect of personrelated work on common mental disorder. Emotional demands at work may be defined as aspects of the work that require sustained emotional effort (53), following the de Jonge and Dormann definition of demands as those aspects of the job which require sustained behavioural, physical, cognitive and/or emotional effort (54, p. 49). Emotional demands are elevated in human service occupations (55), and they may be related to special characteristics of these occupations, such as the imbalanced interpersonal relationship with clients (45). Emotional demands may also Madsen 2012 Social Work Environment and Mental Health 8

15 be related to the confrontation with the problems and suffering of the clients (53;56), and in health care, critical incidents such as treating victims of terror or critically ill patients, may cause emotional responses (57). Also, person-related work requires empathy and sensitivity to the feelings of clients (58), and empathy might elicit sympathy (59) which could be experienced as emotionally demanding. Empirically, emotional demands at work have been associated with indicators of poor mental health including psychological distress (60;61) and depressive and anxiety symptoms (62). Also, a register based study found that women employed in occupations with higher levels of emotional demands were at increased risk of psychiatric treatment for depression (63). The mechanism by which emotional demands might affect mental health is not clear, but they may result in prolonged expenditure of emotional resources or energy as they require sustained emotional effort (53). A causal effect of emotional demands on common mental disorder might then be explained by the conservation of resources theory (64) which states that negative functional and emotional outcomes may occur when resources that an individual values are threatened or lost. Emotional Labour is a term coined by Hochschild (65). She suggested that customer service work involves a special form of emotional work because employees must manage their feelings and emotions in the provision of customer service, to adhere to situation specific feeling rules. One example is the suppression of anger towards a customer, because the expression of anger would be inappropriate according to organizational rules. According to Hochshild (65), employees performing emotional labour may be at increased risk of mental health problems due to an alienation from their true feelings and selves. Zapf (41) uses the term emotion work rather than emotional labour, and argues that such work is a significant part not only of customer service work, but of all types of person-related work. According to this perspective, emotion work has three central characteristics (41): 1) it occurs in face-to-face or voice-to-voice interactions with clients, 2) emotions are displayed to influence other people s emotions, attitudes and behaviours, and 3) the display of emotions Madsen 2012 Social Work Environment and Mental Health 9

16 has to follow certain rules. Emotional labour, or emotion work, has been associated empirically with mental health outcomes such as emotional exhaustion (41;66;67), irritation (41) and psychosomatic complaints (41). This thesis does not examine emotional labour directly, but demands for hiding emotions at work. These demands, though, will likely result in the performance of emotional labour, at least if the employee attempts to meet the demands. The choice to measure demands for hiding emotions was based on the data available, but is also reasonable as emotional labour may be performed without substantial conscious effort (41). Hence, the specific construct of emotion work might be difficult to measure self-reportedly. Demands for hiding emotions could possibly be conceptualized as a type of emotional demands, because the performance of emotion work might involve substantial emotional effort as indicated by its association with emotional exhaustion (41). In the context of this thesis, however, emotional labour and emotional demands are treated as separate constructs for three reasons: 1) emotional labour may not always require sustained emotional effort (41), 2) the two concepts developed as separate entities in different strands of scientific literature, 3) the empirical distribution indicates that the constructs are related but not identical as some occupations have high levels of emotional demands but low demands for hiding emotions (55) EFFECT-MODIFICATION BY GOOD LEADERSHIP If human service work is particularly emotionally demanding because of particular characteristics of the work, such as the confrontation with the clients problems and suffering (43), these types of work may be inherently emotionally demanding and their emotional demands may not be amenable to change. Consequently, it is important to examine if any effects of emotional demands on common mental disorder may be buffered by other factors, which are modifiable. Madsen 2012 Social Work Environment and Mental Health 10

17 According to the conservation of resources theory, negative functional and emotional outcomes may occur when resources that an individual values are threatened or lost (64). Emotional demands at work may result in prolonged expenditure of emotional resources or energy, as they are aspects of the job that require sustained emotional effort (53). Following the conservation of resources theory, the availability of resources will determine the impact of resource loss (64). The theory further states that acknowledgement of accomplishments and tasks, and understanding from superiors are important resources in a Western context (64). Hence, leadership quality may be an important work environment resource, which could have the potential to buffer detrimental effects of emotional demands at work on employee mental health. Good and supportive leadership could also be construed as a type of social support, and social support could buffer effects of stressors (68;69). According to Thoits (68), this buffering may occur because supportive others help the individual cope with the situation (active coping assistance) or provide emotional support leading to an increased sense of self-esteem and mattering (emotional sustenance). In a work context, the leader likely has previous experience with the work demands the employee is facing, and may thus be considered an experientially similar other. Such individuals may offer emotional sustenance in terms of empathic understanding, acceptance of ventilation and validation of feelings and concerns (68). They may also provide active coping assistance in form of assistance in re-appraising the threat, and offering information and advice (68). Finally, they may be a source of social comparison, offering a role model and inspiring hope that one can deal with the situation (68). According to both the social support perspective and the conservation of resources theory, then, good leadership is a work environment factor that might have the potential to buffer any effects of emotional demands at work on common mental disorder. Madsen 2012 Social Work Environment and Mental Health 11

18 1.5. HYPOTHESES Based on the literature presented, the following hypotheses are stated and tested: 1. Employees exposed to work-related violence are at increased risk of developing common mental disorder as indicated by entering psychotropic treatment. (Article 1) 2. Employees in person-related work are at increased risk of developing common mental disorder as indicated by entering antidepressant treatment. (Article 2) 3. This increased risk of common mental disorder is mediated by work environment factors elevated in person-related work, namely emotional demands at work, demands for hiding emotions, and/or workrelated violence. More specifically, there is no direct effect of person-related work on psychotropic treatment when these work environment factors are fixed. (Article 2) 4. The odds of antidepressant treatment in care workers increase more after the employees enter their profession than it did before they entered care work, indicating a causal effect of this work on common mental disorder. (Article 3) 5. Associations between work environment factors and common mental disorder, as indicated by antidepressant treatment, are similar in Denmark and Sweden, substantiating the generalizability of the findings. (Articles 4, 5) 6. The effects of emotional demands at work on common mental disorder, as indicated by antidepressant treatment, is buffered by good leadership. (Article 5) Madsen 2012 Social Work Environment and Mental Health 12

19 2. METHODS The following section presents the methods used in this thesis, including the applied data sources, operationalizations and study populations and the analyses conducted DATA SOURCES This thesis is based on data from the project Social work environment factors And PsychophArmaceuticals (SAPA) which combines self-reported data on work environment exposures with register data on psychotropics purchases and sociodemographic factors. The following section describes the data sources applied WORK ENVIRONMENT DATA The work environment data used in this thesis originate from four Danish and one Swedish work environment studies, namely: 1) the Project on Burnout, Motivation and Job Satisfaction (PUMA), 2) the Copenhagen Psychosocial Questionnaire Study (COPSOQ), 3) the Danish Work Environment Cohort Study (DWECS), 4) the Danish Health Care Worker Cohort - Class of 2004 (DHCWC-2004), and 5) the Swedish Longitudinal Occupational Survey of Health (SLOSH). Table 1 summarizes key information about these studies. PUMA was a three wave open cohort study during designed to examine burnout. PUMA recruited employees from seven human service organizations, and the PUMA participants worked in social work, health care work, elder care work and care work dealing with handicapped persons. Details of PUMA were published by Borritz et al. (70). Madsen 2012 Social Work Environment and Mental Health 13

20 Madsen 2012 Social Work Environment and Mental Health 14 Table 1. Overview of work environment data Study Wave Period for datacollection Method for datacollection Population No. Respondents PUMA Questionnaire Employees in 7 Human service organizations (n= 2,391) Questionnaire Respondents PUMA 1 + new employees in the organizations (n= 2,335) 2005 Questionnaire Respondents PUMA 2 + new employees in the organizations (n= 2,568) COPSOQ a) Questionnaire (2/3, random assignment) b) Telephonic Interview (1/3, random assignment) Representative sample, ages (n=4,000) Questionnaire a) Follow up wave 1 (n=1,698) b) Representative sample (n= 8,000) DWECS 2000 Oct January 2001 (% responserate) DHCWC Oct May 2006 Telephonic Interview Representative sample (supplemented follow-up of DWECS 1995, n= 11,955) a) Questionnaire (9/10, random assignment) b) Telephonic Interview (1/10, random assignment) a) Follow-up of DWECS 2000 (n= 10,131) b) Supplemental random sample, ages (n=943) c) Supplemental random sample, immigrants (n=236) d) New random sample, ages (n=8,545) Social- and health care helpers and assistants (respondents from DHCWC-2004 wave 1, n=5,696) SLOSH 2006 Respondents to SWES (representative Swedish sample, n=9,154 ) Selection criteria for SAPA No. included respondents 1,914 (80.1) a) PNR valid b) No previous response included in SAPA 1,759 (75.3) a) PNR valid b) No previous response included in SAPA 1,747 (68.0) a) PNR valid b) No previous response included in SAPA 2,454 (61.4) a) PNR valid b) No previous response included in SAPA a) 1,281 (75.4) b) 4,732 (60.4) a) PNR valid b) No previous response included in SAPA 8,583 (75.0) a) PNR valid b) No previous response included in SAPA 12,413 (62.5) a) PNR valid b) No previous response included in SAPA 3,708 (65.1) a) PNR valid b) Employed in eldercare in 2005 (self-reported) c) Female 5,985 (65.4) a) Gainfully employed b) Aged years For study details see 1,856 Borritz et al (70) 747 Borritz et al (70) 644 Borritz et al (70) 2,445 Kristensen et al (55) 4,719 Pejtersen et al (71) 8,551 Burr et al (72) 6,743 Feveile et al (73) 2,582 Carneiro et al (74) 4,351 Kinsten et al (75); Magnusson Hanson et al (76) Abbreviations: No.: Number; PUMA: Project burnout, job satisfaction and motivation (Danish Acronym); COPSOQ: Copenhagen psychosocial questionnaire; DWECS: Danish work environment cohort study; DHCWC-2004: Danish health care worker cohort-class of 2004; SLOSH: Swedish longitudinal survey on health; SAPA: Social work environment factors and psychopharmaceuticals.

21 COPSOQ had two waves of data collection in 1997 (COPSOQ I) and (COPSOQ II). COPSOQ I invited participants from a random sample, and COPSOQ II included both a follow up of COPSOQ I participants and a new random sample. Individual dates for questionnaire response were unavailable for COPSOQ I, and all response dates were set to December first Details of COPSOQ were published by Kristensen et al. (55) and Pejtersen et al. (71). DWECS is an on-going cohort study of the Danish working environment, with follow up every five years. The cohort was started in 1990, but the data included in this thesis were collected in 2000 (DWECS 2000) and 2005 (DWECS 2005). At each follow up the population is supplemented with age and migration panels, to remain representative of the Danish working population. Details of DWECS were published by Burr et al. (72) and Feveile et al. (73). DHCWC-2004 was a three-wave study of individuals graduating as social and health care helpers or assistants in Denmark in Social and health care helpers and assistants are primarily trained to work with elder care (77). All 28 Danish schools providing such training were invited to participate, and 27 schools accepted. Details of the DHCWC-2004 were published in Danish by Carneiro et al. (74). SLOSH is an ongoing cohort study which started as a follow up of individuals from the Swedish Work Environment Survey (SWES) from SWES was based on a random sample of gainfully employed Swedish citizens aged in Respondents to SWES were invited to participate in SLOSH. Details of SLOSH were published by Kinsten et al. (75) and Magnusson Hanson et al. (76) REGISTER DATA This thesis uses Danish data from the following registers: the Civil Registration System (78) (sex, date of birth, migration), the Population Education Register (79) (education), the Income Statistics Register (80) (income), Madsen 2012 Social Work Environment and Mental Health 15

22 the Danish Register of Causes of Death (81) (date of death) and the Register of Medicinal Product Statistics (82;83) (purchases of psychotropic medication). Also, data were included from the Swedish Register of Causes of Death (date of death) (84) and the Swedish Prescribed Drug Register (purchases of psychotropic medications) (83) OPERATIONALIZATIONS OF EXPOSURES The operationalizations of the key constructs from articles 1-5 are presented in the articles (see appendices 1-5). The following section of the thesis gives the operationalizations used for the supplementary analyses for article TYPE OF WORK Person-related work was defined to encompass all participants reporting substantial client-contact. The items measuring client-contact are presented in table 2, and substantial client-contact was defined in PUMA as over half the time, in DWECS as three quarters of the time or more, and in COPSOQ by indicating that one s primary work tasks were related to customers or clients. The type of person-related work (health care, social, educational, customer service, other) was defined in PUMA by the organization through which the respondent was recruited. In COPSOQ and DWECS type of work was defined using the Danish Industrial Classification 1993 (85) which is compatible with Eurostat s Statistical classification of economic activities in the European Community (NACE) (86). Table 3 gives an overview of the coding and categorization applied. The industrial classification was chosen for consistency across the datasets, as the classification of PUMA participants was organization based. Madsen 2012 Social Work Environment and Mental Health 16

23 Madsen 2012 Social Work Environment and Mental Health 17 Table 2. Supplementary analysis: measures of work environment exposures CONSTRUCT ITEMS RESPONSE OPTIONS Client contact Emotional demands Demands for hiding emotions PUMA I-III STUDIES COPSOQ II STUDY DWECS 2000 STUDY How much direct contact with clients do you have during 1. All the working hours 2. Working with clients, patients, pupils, children, citizens 4. Working with machines, tools, facilities/plants, an average workweek? a 2. More than half of the working hours 3. Less than half of the working hours 4. Never/almost never What are your primary daily work tasks? 1. Working with contact to customers etc. 3. Working with language, figures, writing, communication transportation 5. Working with animals, plants 6. Other, write: Are you in contact with people who are not employed at your workplace when conducting your work? (e.g. customers, clients, passengers, pupils?) Does your work put you in emotionally disturbing situations? 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever Is your work emotionally demanding? 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. to a very small extent Do you get emotionally involved in your work? 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent Does your work require that you hide your feelings? 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent Violence Have you been exposed to threats of violence at your workplace during the last 12 months? Table 2 Continues Have you been exposed to physical violence at your workplace during the last 12 months? 1. No 2. yes 1. No 2. Yes 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent 1. Yes, daily 2. Yes, weekly 3. Yes, monthly 4. Yes, a few times 5. No 1. Yes, daily 2. Yes, weekly 3. Yes, monthly 4. Yes, a few times 5. No 1. Almost all my working hours 2. Approx. ¾ of the working hours 3. Approx.½ of the working hours 4. Approx. ¼ of the working hours 5. Only few working hours 6. None at all 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent 1. To a very large extent 2. To a large extent 3. Some-what 4. To a small extent 5. To a very small extent 1. No 2. Yes, from a colleague 3. Yes, from a manager 4. Yes, from subordinates 6. Yes, from clients* 1. No 2. Yes, from a colleague 3. Yes, from a manager 4. Yes, from subordinates 5. Yes, from clients*

24 Madsen 2012 Social Work Environment and Mental Health 18 Table 2 Continued Quantitative demands Quantitative demands Do you have to work very fast? 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever Is your work unevenly distributed so it piles up? 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever How often do you not have time to complete all your work tasks? Influence Do you have a large degree of influence concerning your work? Social support 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever Do you have any influence on what you do at work? 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever Can you influence the amount of work assigned to you? 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever How often do you get help and support from your colleagues? How often do you get help and support from your immediate superior? 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 1. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 6. Not relevant 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 6. Not relevant 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 6. Have no colleagues 1. Always 2. Often 3. Sometimes 4. Seldom 5. Never/hardly ever 6. Have no superior Abbreviations: PUMA: Projekt Udbrændthed, Motivation, og Arbejdsglæde (Danish Acronym); COPSOQ: Copenhagen Psychosocial Questionnaire; DWECS: Danish Work Environment Cohort Study. adepending on the organization and the types of clients dealt with, the term client was exchanged with resident, inmate or patient.

25 Table 3. Supplementary analysis: definition of type of person-related work by industry used in COPSOQ and DWECS TYPE OF PERSON-RELATED WORK Health care INDUSTRY ACCORDING TO THE DANISH INDUSTRIAL CLASSIFICATION Hospital activities General medical practice activities Dental practice activities Other human health activities Residential institutions for physically or mentally handicapped adults Residential nursing homes and sheltered homes Home help Day institutions for elderly people Rehabilitation institutions Refugee centres Associations combatting diseases and performing activities aimed at social work, etc Special schools for handicapped children Fire service activities Education Primary education (except Special schools for handicapped children ) General secondary education Technical and vocational secondary education Higher education Driving school activities Other adult education Child day-care in private homes Day nurseries Kindergartens After school centres Age-integrated institutions Recreation centres for young people Social work Customer service Justice and judicial activities, law and order activities Police Compulsory social security activities Social work activities with accommodation (except Residential care activities for disabled adults and Residential care activities for the elderly) Other social work activities without accommodation Employment exchange 45 Construction 50 Sale and rep. of motor vehicles, sale of auto. fuel 51 Wholesale except of motor vehicles 52 Retail trade and repair work except of motor vehicles 55 Hotels and restaurants 60 Land transport and transport via pipelines 61 Water transport 62 Air transport 63 Supporting transport activities 64 Post and telecommunications 65 Finance 66 Insurance 67 Activities auxiliary to finance 70 Real estate activities 71 Renting of transport equipment and machinery 72 Computer and related activities 73 Research and development 74.2 Consulting architectural activities 74.4 Advertising Temporary employment agencies Security and surveillance activities Cleaning activities Photographers Packaging activities, etc Envelope addressing activities Activities of interior designer Charitable trusts and foundations Madsen 2012 Social Work Environment and Mental Health 19

26 EMOTIONAL DEMANDS Emotional demands at work were measured by the three items presented in table 2. A scale was constructed as the mean of the three items scored with equally spaced response categories from For presentational purposes the continuous scale was divided by 10, yielding a scale from High versus low emotional demands were defined dichotomously by the median value from DWECS 2000 (41.67) DEMANDS FOR HIDING EMOTIONS Demands for hiding emotions were measured by a single item as presented in table 2. A continuous score was constructed scoring each response category equally spaced from 0-10 with higher scores indicating higher demands. High versus low demands for hiding emotions were defined by collapsing to a very large extent and to a large extent as high and the remaining categories were defined as low WORK-RELATED VIOLENCE Exposure to work-related violence was defined as reporting being exposed to violence or threats in the workplace during the past 12 months, measured by the items presented in table 2. Threats were included in the definition to conform with the World Health Organization s definition of violence (31). Madsen 2012 Social Work Environment and Mental Health 20

27 2.3. OPERATIONALIZATION OF OUTCOME Psychotropic (antidepressant, anxiolytic, hypnotic) treatment was used in this thesis as an indicator for clinically significant common mental disorder. This choice was based on a number of considerations, which are presented in the following section. In clinical psychiatry, the psychiatric interview by a trained mental health professional is the most important method of diagnosing mental disorders (87) and this method is considered the most valid for diagnosing mental disorders (88). Applying this measure, however, may not be feasible in large-scale epidemiological studies due to logistic and financial challenges (89). Furthermore, this measure was unavailable for this thesis which was based on existing data. Other measures for common mental disorder include self-reported data such as asking respondents if they have been diagnosed with a common mental disorder or to fill out symptom scales, such as the general health questionnaire (90). Self-report measures, however, may be problematic because of reporting issues such as recall and social desirability bias (91;92) and their correspondence with clinically significant mental disorder is sometimes unclear (93). A further challenge for the present analyses, was a lack of consistent selfreported measures across the included studies, and the self-reported nature of the measures; as the examined exposures were measured by self-report, a non-self-reported outcome was preferred to avoid common method bias (94). In Denmark, all psychiatric treatment, both in- and outpatient, is registered since 1995 (95). From the Danish Psychiatric Central Research Register it is thus possible to obtain records of psychiatric treatment and diagnoses for research purposes (95). Most cases of common mental disorder are, however, not treated (1;96), and amongst those who are treated, individuals in specialist treatment likely suffer from more severe disorder (97). For the present analyses, examining associations in the working population, this register may therefore leave out many relevant cases of common mental disorder. Madsen 2012 Social Work Environment and Mental Health 21

28 Purchases of prescription medications at Danish pharmacies are also registered at the individual level since 1995 in the Register of Medicinal Product Statistics (82) and purchases of psychotropic medication were chosen in this thesis as an indicator of common mental disorder. The main advantages of this outcome measure compared to diagnostic interviews or self-reported outcome measures are the cost-efficiency, the minimal loss to follow up and the day-to-day measurement. When applying other outcome measures which require respondent participation, caseness of ill-health may be underestimated because individuals with poor health might be less likely to participate at follow up (98) and because the follow up is carried out at a specific time. Compared to self-reported measures, psychotropic treatment further has the advantage that it is nonself-reported which may be preferable when the examined exposures are self-reported. Also, the measure likely has substantial validity for clinically significant conditions as it reflects a clinical decision that psychotropic treatment is warranted. Compared to the psychiatric register, the main advantage of psychotropic treatment is the inclusion of less severe cases of common mental disorder which may not be specialist-treated. It must be noted, though, that despite these advantages of using psychotropic treatment as an indicator for common mental disorder, several important methodological concerns exist regarding the chosen outcome. Most notably, although most psychotropics are used to treat common mental disorder (99-101), the various types of psychotropics are used to treat different disorders, and antidepressants for instance are also given for anxiety disorders (100). Hence, the effects reported in this thesis cannot be interpreted as effects on any specific common mental disorder. The methodological issues concerning the outcome measure are discussed more fully in a later section of the thesis (see section 4.1.2) DEFINING PSYCHOTROPIC TREATMENT The Register of Medicinal Product Statistics (82) classifies all medications according to their main indications following the World Health Organization s Anatomical Therapeutic Chemical Classification System (ATC) (102). Madsen 2012 Social Work Environment and Mental Health 22

29 For this thesis, psychotropics were defined as medications N06A (antidepressants), N05B (anxiolytics), or N05C (hypnotics) and data were included from 1995 onwards. The medication data were updated during the project, and the available follow up period expanded from the analyses for articles 1, 2, and 3 ( ), to the supplementary analysis for article 2, as medication data for 2009 and 2010 became available. The specific outcome definitions varied between the articles and are described in the separate articles (appendices 1-5). For the supplementary analysis for article 2, the outcome was defined as follows: Antidepressant treatment was defined by at least one purchase of antidepressants, as indicated by ATC-code N06A. Anxiolytic or hypnotic treatment was defined by at least one purchase of anxiolytics or hypnotics, as indicated by ATC-codes N05B and N05C, in individuals without antidepressant treatment. Hence, individuals purchasing both antidepressants and either anxiolytics or hypnotics were classified as in antidepressant treatment. This definition was based on the findings in article 1 (see appendix 1) that patterns for treatment with both antidepressants and anxiolytics and antidepressants only were similar COVARIATES The covariates included in the analyses varied, and the covariates used in the articles are described in the separate appendices (appendices 1-5). For the supplementary analysis for article 2, the following covariates were included: Data on sex and date of birth were included from the Civil Registration System (78). Cohabitation (living with a partner or spouse, yes/no) was measured by self-report. Education was obtained through the Population Education Register (79) and defined as the norm length of the respondents highest attained education. Income was obtained through the Income Statistics Register (80), and defined as income after tax and interests in the year of responding to the questionnaire. Migration data were obtained through the Civil Registration System and death through the Danish Register of Causes of Death (81). Madsen 2012 Social Work Environment and Mental Health 23

30 2.5. STUDY POPULATIONS The study populations differed between the analyses and were chosen for availability of key measures. The study populations for articles 1-5 are presented in the separate articles (see appendices 1-5). Briefly, article 1 uses data from PUMA I-III, COPSOQ I-II, and DWECS , and article 2 applies data from DWECS Article 3 is based on the DHCWC-2004 and DWECS Articles 4 and 5 use data from DWECS 2005 and SLOSH. This section focuses on study population for the supplementary analyses for article 2. The supplementary analysis for article 2 used data from PUMA I-III, COPSOQ-II, and DWECS 2000, with a total of 12,766 employed first-time respondents. I excluded 1,916 individuals with purchases of any psychotropic during 1,494 days before baseline to examine incident treatment. The length of exclusion period used to define prevalent use (1,494 days) was chosen because it was the maximum available for all studies. Further, 334 individuals with poor mental health at baseline and 544 individuals with missing data on any covariates were excluded, yielding a final study population of 9,972 individuals. The characteristics of the study population are shown in table 4. Madsen 2012 Social Work Environment and Mental Health 24

31 Table 4. Supplementary analysis: characteristics of participants and incident psychotropic treatment Participants Antidepressants treatment, No. (%) Anxiolytics/hypnotics treatment, No. (%) No. Mean (SD) No. (%) No. (%) Total 9, (7.2) 681 (6.8) Type of work Health care 1, (9.1) 146 (8.4) Education (7.1) 44 (7.1) Social (10.3) 59 (7.3) Customer service 1, (6.4) 63 (6.0) Other person-related 1, (6.5) 78 (6.0) Non-person-related 4, (6.3) 291 (6.5) Emotional demands Score, (2.49) high 4, (8.2) 308 (7.6) low 5, (6.5) 373 (6.3) Demands for hiding emotions Score, (2.70) to a very large extent (10.9) 26 (8.3) to a large extent (8.3) 74 (7.8) some-what 3, (7.7) 253 (7.3) to a small extent 2, (7.0) 152 (6.2) to a very small extent 2, (5.9) 176 (6.3) Work-related violence Yes 1, (9.5) 76 (7.5) No 8, (6.9) 605 (6.8) Sex Female 5, (8.2) 442 (8.0) Male 4, (6.0) 239 (5.4) Cohabitation No 2, (7.2) 127 (6.2) Yes 7, (7.2) 554 (7.0) Age, years 41.5 (10.5) Education, years 13.1 (2.46) Income, Dkk per year 181,819 (88,266.0) Abbreviations: No.: Number; SD: Standard deviation. Madsen 2012 Social Work Environment and Mental Health 25

32 2.6. STATISTICAL ANALYSES This section gives an overview of the main statistical methods applied in this thesis. More specifically, the section introduces the Cox proportional hazards regression analysis, the competing risks framework, mediation analysis, individual participant meta-analysis, and the principals applied for confounder selection COX PROPORTIONAL HAZARDS REGRESSION Articles 1, 4, 5 and the supplementary analyses for article 2 applied Cox proportional hazards regression analyses. The following presentation of Cox regression analysis is based on the text by Kleinbaum & Klein (103). The Cox proportional hazards model is a regression model for examining time-to-event outcomes. The model specifies that the hazard of an event at any time t, h(t), is a function of the baseline hazard h0(t) and the exponential expression e to the power of the sum of the included covariates X1, X2,..., Xi, multiplied by their respective regression parameters β1, β2,..., βi. The hazard ratio (HR) estimates the relative effect of a covariate in the model, and is the ratio of the hazard rate among exposed individuals divided by that of the unexposed group. The baseline hazard is included in both numerator and denominator and thus need not be estimated. The Cox proportional hazards model is a robust semiparametric model, and yields regression coefficients that are close to the underlying parametric model, without having to fully specify this model. Hence, Cox regression is a good choice when the underlying parametric model is unknown. The model assumes, however, that the effects of the covariates remain constant over time the proportional hazards assumption. This assumption may be tested empirically, for instance by visual inspection of the log-log survival plots. If the log-log curves for the examined exposure groups are non-parallel the assumption is violated. In this case, data may be analysed by dividing follow-up into periods with proportional hazards (extended Cox modelling). Madsen 2012 Social Work Environment and Mental Health 26

33 COMPETING RISKS In time-to-event analysis with multiple outcomes, the occurrence of one outcome may prevent the occurrence of another. If examining death from cancer, for instance, this outcome cannot occur if an individual dies from a heart attack first. Such outcomes are referred to competing risks (104) and were applied in article 1 and the supplementary analysis for article 2 as the outcomes of different types of psychotropics were defined as mutually exclusive. When analysing competing risks data, Cox regression may be employed to calculate cause-specific hazard ratios (104). These ratios assess the relative hazard rate for experiencing the corresponding outcome at time t, in individuals who have experienced none of the examined outcomes at time t (104). Technically, the cause-specific hazard ratio is estimated by treating the competing outcomes as censored observations when constructing the model (104). This approach is valid for interpreting the relative associations between an exposure and the outcomes (105), as is the purpose of this thesis. It should be noted, though, that causespecific hazard ratios do not correspond to cumulative incidence functions unless the examined outcomes are independent, an issue which complicates the estimation of absolute risk of the outcomes in competing risks analysis (105) MEDIATION A mediating factor is a step in the causal pathway between an exposure and an outcome (40). Article 2 and its supplementary analyses deal with mediation, and the potential mediating relations examined there are presented in figure 1. Madsen 2012 Social Work Environment and Mental Health 27

34 One traditional approach to examining the extent of mediation by a factor (Z) in the relation between an exposure (X) and outcome (Y), is to compare the regression parameter for X in a model of the effect of X on Y (βx), to the regression parameter for X when Z is controlled (βx_z) (106). βx then estimates the total effect of X on Y, βx_z estimates the direct effect of X on Y, and βx-βx_z estimates the indirect effect of X on Y through Z. This method has been used in linear regression models, but may be problematic when these models cannot be applied, e.g. due to a dichotomous outcome (106;107). Petersen et al. (108) distinguish between controlled and natural direct effects. The controlled direct effect is defined as...the difference in counterfactual outcome if the individual was unexposed and her intermediate variable was controlled (or set) at level Z=z versus the counterfactual outcome if she was exposed and her intermediate variable set at the same level Z=z. (108, p. 277) In contrast, the natural direct effect direct effect is defined as:...the difference in counterfactual outcome if the individual was unexposed Figure 1. Mediating relations between person-related work and psychotropic treatment Madsen 2012 Social Work Environment and Mental Health 28