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Depression in the workforce: the intermediary effect of medical comorbidity
Journal of Affective Disorders 128S1 (2011) S29–S36
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Journal of Affective Disorders j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / j a d
Depression in the workforce: the intermediary effect of medical comorbidity Roger S. McIntyrea,b,c,d, *, Samantha Liauwc,e , Valerie H. Taylorf a Department
of Psychiatry, University of Toronto, Toronto, ON, Canada of Pharmacology, University of Toronto, Toronto, ON, Canada Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada d Institute of Medical Science, University of Toronto, Toronto, ON, Canada e McGill University, Montreal, QC, Canada f Department of Psychiatry, McMaster University, ON, Canada b Department c
article info
abstract
Keywords: Workforce disability Depression Medical comorbidity Obesity Diabetes Cardiovascular disease
Background: It is amply documented that mood disorders adversely affect job satisfaction, workforce productivity, and absenteeism/presenteeism. It is also well documented that mood disorders are an independent risk factor for several chronic medical disorders (e.g., obesity, diabetes mellitus, cardiovascular disease). Emerging evidence indicates that the workforce dysfunction associated with depression is partially mediated by medical comorbidity. Methods: We conducted a PubMed search of all English-language articles published between 2005 and July 2009 with the following search terms: major depressive disorder and depression, cross-referenced with work productivity, disability, economic cost, absenteeism, presenteeism, and medical comorbidity. Articles selected for review were based on adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality. Results: Mood disorders are the most impairing condition amongst working adults. It is estimated that approximately 35–50% of employees with depression will take short-term disability leave at some point during their job tenure. Moreover, 15–20% of the workforce will receive short-term disability benefits during any given year; the annual income of individuals affected by depression is reduced by approximately 10% when compared to unaffected employees. Chronic stress-sensitive conditions independently contribute to workforce maladjustment and associated disability. The mood disorder population is differentially affected by several stress-related medical conditions resulting in greater impairment in the workforce. Conclusion: Disability modelling in the depressed employee has emphasized the complex interrelationship between depressive symptoms, workforce stress, and consequent disability. A more refined model must include the effects of chronic medical conditions as a powerful mediator and/or moderator of workforce impairment. Multidisciplinary interventions have been demonstrated to reduce, but not eliminate workforce disability related to depression, underscoring the need for elucidating other modifiable factors. Screening, treatment, and prevention initiatives need to target chronic medical conditions in depressed employees in order to reduce overall workforce disability. © 2010 Elsevier B.V. All rights reserved.
1. Introduction Major depressive disorder is a highly prevalent chronic condition estimated to affect approximately 10–16% of individuals at some time in their life (Kessler et al., 2003). It * Corresponding author. Department of Psychiatry, University of Toronto. 399 Bathurst Street, Toronto, ON, Canada, M5T 2S8. Tel.: +1 416 603 5279. E-mail address: [email protected] (R.S. McIntyre). 0165-0327/$ – see front matter © 2010 Elsevier B.V. All rights reserved..
has been further reported that 15.7% of employed individuals (19.5% of women, 11.4% of men) met lifetime criteria for major depressive disorder and that 8.6% (10.2% of women, 5.9% of men) met 12-month criteria (Marcotte et al., 1999). The burden of illness attributable to depression is staggering, with projections that depression will be the second leading cause of disability-adjusted life years worldwide by the year 2020 (Murray and Lopez, 1997a; Wells et al., 1989).
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Greenberg et al. (2003) estimated that the annual cost of depression in 2000 was $83.1 billion. This estimate represents a 7% increase (from $77.4 billion) after adjusting for inflation when compared to an estimate a decade earlier (Greenberg et al., 1993). Comparative cost-of-illness studies have also reported that mood disorders, and their associated comorbidity, are the most costly conditions to employers (Druss et al., 2001, McIntyre et al., 2008). Moreover, population-based estimates of illness-associated morbidity have reported that neuropsychiatric illness accounts for approximately 15% of overall disability-adjusted life years in the general population (Murray and Lopez, 1997b). The majority of costs associated with major depressive disorder are indirect, reflecting psychosocial impairment and decreased workforce productivity (Birnbaum et al., 2010b). Underdetection, delay in diagnosis, misdiagnosis, guidelinediscordant care, and insufficiently applied treatment interventions remain modifiable deficiencies that account for a disproportionate number of days lost to work due to presenteeism and/or absenteeism (Wang et al., 2007). In addition to the economic consequences, depression-related workforce impairment has a deleterious effect on identity, social participation, and measures of physical and mental well being (Lauber and Bowen, 2010). During the past decade, many commentators have pressed the point that national and regional economies have shifted from primary industry to “human capital” or the “knowledge economy” (Birnbaum et al., 2010a). Major depressive disorder and related “stress conditions” (e.g., burnout) are the most common causes of decreased educational attainment and workforce performance in developed economies. Against this background, timely detection, diagnosis, treatment, and management of mood disorders in the working population has medical, economic, political, and social implications. This paper reviews the topic of depressive disorders and their impact on workforce productivity. It is not meant to be a comprehensive review of the topic, as this has been amply reviewed elsewhere (Hirschfeld et al., 2000, Lerner and Henke, 2008; Simon, 2003), but rather a succinct review with a particular emphasis on the hazardous effects of comorbid medical conditions in depressed employees and its intermediary effect on decreased workforce productivity. 2. Methods We conducted a PubMed search of all English-language articles published between 1966 and June 2010 with the following search terms: major depressive disorder and depression, cross-referenced with work productivity, disability, economic cost, absenteeism, presenteeism, and medical comorbidity. Articles selected for review were based on adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality. 3. Results Several original studies, reviews, and meta-analyses have addressed the impact of depression on workforce adjustment, attendance, absenteeism, presenteeism, short- and long-term disability, job strain, satisfaction, and performance
(Kessler et al., 1999). The results of these endeavours have been published and comprehensively reviewed elsewhere (Katon, 2009; Lerner et al., 2004; Mino et al., 2006; Simon et al., 2000; Simon, 2003; Williams and Schouten, 2008). Herein, we highlight several key findings. Kessler et al. (2006) reported that major depressive disorder results in 27.2 annualized lost workdays amongst respondents in the National Comorbidity Survey-Replication (NCS-R). A separate report by Kessler and colleagues (1999) concluded that while 17–21% of the workforce experiences short-term disability during any given year, 37–48% of workers with depression take short-term disability leave at some time during their job tenure (Goldberg and Steury, 2001). McIntyre et al. (2008), using data from the Canadian Community Health Survey (CCHS) reported that the annual income amongst adults 18 or older with major depressive disorder was approximately 10% lower when compared to adults without a lifetime history of a psychiatric disorder ($36 800 vs. $40 300). Moreover, individuals with depression had a higher risk of experiencing at least one mental health disability day within the past two weeks when compared to individuals without a mood disorder. Moreover, the odds of reporting satisfactory job security were much lower in individuals with major depressive disorder when compared to the general population (McIntyre et al., 2008). In addition to affecting a proband with depression, the functional consequences of depression extend to other family members and caregivers. This “ripple effect” is also apparent in terms of the impact of depression on a family’s socioeconomic status/attainment and subsequent illness vulnerability (i.e., caregiver burnout that accompanies mental illness can result in increased vulnerability for incident mental illness and decreased productivity in the caregiver) (Steele et al., 2010). Moreover, work-related financial stressors have been identified as a susceptibility factor to pediatric depression (Goodman et al., 2003). 3.1. Risk factors for workforce impairment In 1908, Robert Yerkes and John Dodson described an inverted U-shaped curve characterizing the relationship between stress and performance (Couser, 2008). Burnout in the workforce is frequently the result of unremitting, uncontrolled and excessive stressors perceived by the individual (e.g., the Job Strain Model, Demand-Control Model) (Virtanen et al., 2007). An extensive body of literature has documented the adverse effects of stress on job strain as a non-specific risk factor for adverse coping, depressive symptoms and episodes, antidepressant utilization, and early retirement (Bonde, 2008; Virtanen et al., 2007). Specific factors mediating this association include high job demand and low decision latitude and social support (emotional and instrumental) (Stoetzer et al., 2009). Moreover, serious conflict, exclusion by superiors, and exclusion by coworkers have been specifically associated with increased psychological distress and/or depression in the workforce (the odds ratios for these variables have ranged from 1.2 to 2.3, underscoring their salience). Intuitively, stressors within and outside of the workforce independently contribute to the risk of developing major depression. Despite this axiomatic notion, relatively few
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studies have evaluated whether the work environment interacts with psychosocial factors outside of the workplace as a mediating factor conferring an increased risk of major depression. Notwithstanding, a recently published population-based study reported that job strain, chronic stress, negative life events, and childhood traumatic events were all important risk factors for developing depressive episodes. The risk of developing depression increased in a dose-response pattern as a function of number of stressors. Nonetheless, psychosocial stressors within the job environment did not interact with factors outside of the workplace in relation to the risk of depression (Wang and Schmitz, 2010). A population-based Canadian study reported that specific subcomponents of work stress and depression differed between men and women. High job strain, low levels of social support in the workplace, low job security, and increased psychological demands were associated with major depressive episodes among men. Among women, lower levels of social support and lack of decision authority were associated with major depressive episodes. Low levels of skill discretion were inversely associated with major depressive episodes among women (Blackmore et al., 2007). A separate study on a large cohort of employees (n = 4133) in a Danish workforce setting analyzed the impact of psychosocial work characteristics on the incidence of depressive symptoms as part of a 5-year prospective study (Rugulies et al., 2006). It was concluded that among women, low influence at work demonstrated a dose-response relationship with risk of severe depressive symptoms; amongst men, neither influence at work, nor social support from supervisors was associated with depressive symptoms. Job insecurity, however, was predictive of depression in the male subpopulation. Social capital refers to the relationship between an individual and groups of people, and is proposed as a protective factor for mental health (Kouvonen et al., 2008). Amongst individuals employed in the public sector, it is reported that low self-reported social capital was associated with a greater odds of being prescribed antidepressant medication and/or receiving a diagnosis of depression (Kouvonen et al., 2008). Social capital has been divided into both vertical and horizontal components. Vertical social capital refers to norms of respect and networks of trusting relations between people who are interacting across explicit formal or institutionalized power or authority gradients in society (Oksanen et al., 2010). The horizontal component refers to relations of trust and reciprocity between individuals and groups at the same hierarchical level (Oksanen et al., 2010). Oksanen et al., evaluated whether or not vertical and horizontal social capital in the workforce differentially predicted depression in a large cohort (n = 25 763) of Finnish public sector workers. They reported that employees with either low vertical or horizontal social capital were 30–50% more likely to be diagnosed as either having depression or to start antidepressant treatment than their counterparts with high social capital. Presenteeism is often used interchangeably with “sickness presenteeism” and “presence”, referring to an employee attending work despite suboptimal performance. It has been
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reported that 63–83% of employees report having gone to work despite illness on at least one occasion during the previous year (Bergstrom et al., 2009). Sickness presenteeism has been identified as a risk factor for absenteeism in both the public and private sector for both sexes (Bergstrom et al., 2009). A dose-response gradient is implicated insofar as the number of sickness presenteeism episodes increases the likelihood of absenteeism. These results suggest that interventions that are intended to decrease sickness absence may lead to an increase in sickness presenteeism, with subsequently absenteeism due to sick leave in the long run (Bergstrom et al., 2009). Taken together, the foregoing observations indicate that in some cases sick leave may be preferred as a way of minimizing overall compromised workplace productivity. Presenteeism has been consistently identified as accounting for the majority of economic cost due to loss productivity of depression. As presenteeism is a “hidden-cost of depression” there is a need to identify a clinically meaningful and sensitive measure of this construct. Scales evaluating presenteeism include, but are not limited to, the Work Limitations Questionnaire and the Stanford Presenteeism Scale (Koopman et al., 2002; Lerner et al., 2004; Sanderson et al., 2007). Preliminary studies also indicate that presenteeism may be a stronger correlate of depression and anxiety than is absenteeism (Aronsson and Gustafsson, 2005). It should be highlighted that presenteeism is not always an undesirable outcome in an individual with depression in the workforce as the social support and structure as well as financial advantages of remaining in the workforce may be preferred to short- and long-term disability wherein there is a divorcing of the individual from possible psychosocial and financial gains of the workforce (Sanderson et al., 2007). These associations need to be addressed on an individual basis, evaluating which approach (i.e., prescribed disability leave or presenteeism) will ultimately provide the optimal outcome for the employee. 3.2. Comorbidity and workforce impairment in depressed populations Individuals with mood disorders are differentially affected by co-occurring psychiatric and medical conditions (Fleischhacker et al., 2008; McIntyre et al., 2007b; McIntyre, 2009). Accumulated evidence indicates that overall psychosocial impairment associated with mood disorders is mediated to a significant degree by co-occurring conditions (McIntyre et al., 2004; McIntyre et al., 2006a; McIntyre et al., 2007a; McIntyre et al., 2009). For example, attention deficit hyperactivity disorder and migraine headaches, conditions with reported high prevalence in individuals with mood disorders, are independently associated with impaired work performance (de Graaf et al., 2008; Kessler et al., 2010; McIntyre et al., 2006b). Concomitant medical comorbidity is also a significant contributor to both the employee and employer costs associated with depression. During the past few years, confronting the obesity epidemic has become a major policy focus globally. From a medical and public health perspective, rising rates of obesity are resulting in commensurate increases in the incidence of many chronic diseases, including type 2 diabetes, cardiovascular disease, and several
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Conventional Modelling Workforce Dysfunction
Mood Disorder
Proposed Modelling Mediational Model Mood Disorder
Workforce Dysfunction
Overweight/obesity Diabetes mellitus Cardiovascular disease Pain disorders Dementing disorders (mild cognitive impairment) Other chronic stress-sensitive medical disorders
Moderational Model Mood Disorder
Workforce Dysfunction Overweight/obesity Diabetes mellitus Cardiovascular disease Pain disorders Dementing disorders (mild cognitive impairment) Other chronic stress-sensitive medical disorders
Fig. 1. The association between mood disorders and workforce impairment: the meditational/moderational effects of chronic medical conditions.
types of cancer (Field et al., 2001). This has resulted in increased concern about the rising costs of heath care for this population, given that approximately 30% of the population is obese and the current obesity epidemic is expected to worsen in the next few years (Flegal et al., 2002). Moreover, rising obesity rates and its related complications have significant economic consequences for employers (Finkelstein et al., 2003). For example, it has been reported by a nationally representative 1000-person company, that overweight/obesity results in an increase in annual costs of $277 000. The reasons for the increased costs were categorized as indirect referring to absenteeism, disability, premature mortality, presenteeism, and workers’ compensation (Finkelstein et al., 2005; Fontaine et al., 2003; Trogdon et al., 2008) (Fig. 1). High rates of medical comorbidity also contribute to the costs associated with mood disorders, since individuals with mood disorders have higher rates of overweight/obesity, diabetes mellitus, hypertension, dyslipidemia, and cardiovascular disease when compared to the general population (Taylor et al., 2010). Emerging evidence also indicates that the functional impairment from obesity may be mediated in part by the presence of a co-occurring mental disorder (Bruffaerts et al., 2008). Several factors subserve the adverse outcome in the medically comorbid depressed individual including, but not limited to, the fact that persons with comorbid conditions often have a poorer treatment
response, a worse course of illness, and as described above, comorbid medical conditions are associated with independent effects on workforce productivity (Burton et al., 2008; Gates et al., 2008; Goetzel et al., 2010). 3.3. Interventional studies The burden and hazards posed by depression in the workforce provides the impetus for both screening interventions and the initiation of primary and secondary prevention strategies (see Gelenberg, 2010, for a review of depression screening and diagnostic tools, symptom surveillance measures and adverse event measurement scales. Many risk factors for depression are non-modifiable and are not the purview of the employer (e.g., low selfesteem, low self-efficacy, social stigma) (Couser, 2008). Nevertheless, factors such as social support, work demand, stress management, and interpersonal relations are possible targets for workforce prevention and treatment initiatives. Randomized controlled trials indicate that stress-management initiatives based on cognitive behavioural approaches carried out in the workforce significantly improve depressive symptoms. Stress management programs emphasize the importance of sufficient sleep and rest, regular exercise, maintaining good interpersonal relationships, challenging anxiety provoking and depressogenic thoughts, and muscle relaxation (Mino et al., 2006).
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Depression screening and enhanced care programs have been shown to significantly improve treatment and clinical outcomes amongst depressed individuals (Wang et al., 2007; Williams and Schouten, 2008). Historically, employer purchasers have been reluctant to invest in enhanced depression care programs in the workforce largely based on uncertainty on the return of investment (Wang et al., 2007). Wang et al., evaluated the impact of depression screening, vigorous outreach and care management of depressed workers employed by several large national companies (totalling approximately 150 000 workers). The intervention was a structured telephone program that assessed the needs for treatment, facilitated entry into in-person treatment, monitored and supported treatment adherence, and provided a structured psychotherapeutic intervention by telephone. Depression severity was evaluated with the Quick Inventory for Depressive Symptoms Self Report (QIDS-SR), www.ids-qids.org/, while work performance was evaluated with the WHO Health and Productivity Questionnaire (HPQ), www.hcp.med.harvard.edu/hpq/. The HPQ assesses four dimensions of work functioning: work hours, job performance, job turnover, and critical workforce incidence. After 6 and 12 months, the intervention group had significantly lower QIDS-SR scores, significantly higher job retention, and more hours worked among the employed than the usual care subjects. The increase in number of hours worked was equivalent to an annualized effect of approximately two and a half weeks of work (Wang et al., 2007). Early identification of problematic interpersonal relationships may also diminish the risk of employees developing adverse stress responses in the workforce (Stoetzer et al., 2009). The Agency for Healthcare Research and Quality (AHRQ) has developed the Healthcare Effectiveness Data and Information Set (HEDIS) treatment guidelines to measure antidepressant management specifying an 84-day acute phase as well as an overall 180-day continuation treatment phase (Birnbaum et al., 2010a). Adherence to antidepressants as measured by the HEDIS among privately insured patients with depression reported that 51% of patients adhered to treatment through the acute phase and 42% maintained treatment throughout the continuation phase (Akincigil et al., 2007). The high rate of discordance with guideline recommended care has also been reported in populationbased studies (Kessler et al., 2008). Others have reported that non-adherence to HEDIS treatment guidelines are more likely to receive short-term disability claims (Burton et al., 2007). Birnbaum et al., evaluated economic outcomes associated with compliance including both direct and indirect costs, by using data from two U.S. employers’ privately insured medical and prescription administrative claims databases (2004–2006). Among antidepressant users, medical costs were not statistically different for compliant versus noncompliant patients. Medication costs were higher for compliant patients due to increased antidepressant costs. Absenteeism rates were lower for compliant patients with antidepressant use ($3857 vs. $4907; p = 0.041) and among depressed patients ($3976 vs. $5899; p = 0.047), presenteeism costs were higher for depressed compliant patients ($19 170 vs. $15 829; p = 0.011) (Birnbaum et al., 2010a,b). Notwithstanding the lower absenteeism costs, the
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overall medical costs were not lower in the compliant patients. A Canadian study evaluated whether guideline-concordant antidepressant prescription was associated with improved disability outcomes and the relationship between guidelineconcordant antidepressant use and length of disability (Dewa et al., 2003). It was reported that workers using recommended first-line agents (and doses) were significantly more likely to return to work rather than claim long-term disability benefits or leave their employment. It was also reported that early intervention was significantly associated with a shortened disability episode among employees who had at least one antidepressant claim indicating that early intervention was associated with a reduction in disability of about three weeks (Dewa et al., 2003). The costs of medication treatment need to be weighed against the risks conferred by the side effects of therapy, with consideration given to the types of treatments prescribed (Kennedy et al., 2009). Endeavors (e.g., enhanced awareness campaigns, healthy lifestyle program access) that aim to minimize the iatrogenic risk for comorbid physical illness are exigently needed. Other interventional opportunities for individuals with mental illness in the workforce are destigmatization efforts and improved access (facilitated by employment assistance programs) to appropriate mental health services. The implementation and evaluation of these programs is still largely unexplored but should include a provision of basic information about symptoms, course of illness and treatment options, and involve active open communication between employee, employer, health care provider and other involved third parties (Laxman et al., 2008). The effect of workplace health promotion and “stressmanagement programs” (some of which are telephonebased and/or computer-based) on the risk of depression and anxiety has been extensively reviewed elsewhere (Grime, 2004, Martin et al., 2009; Zivin et al., 2009). Overall, results indicate that small, yet positive, effects of such interventions on the symptoms of depression are observed. Inconsistent effects on composite mental health measures have also been reported (Richardson and Rothstein, 2008; van der Klink et al., 2001). Several studies utilizing disparate designs (e.g., randomization, economic simulation) across populationbased, clinical, and workplace settings have reported a positive return on investment for disease management programs that target multiple chronic conditions, including depression (Goetzel et al., 2005; Lo Sasso et al., 2006). This finding is mirrored by results of a recent study by the Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion that reported that low-cost policy or environmental change interventions in worksites are more likely to be cost saving with robust improvement in employee wellness (Trogdon et al., 2009). 4. Conclusion Major depressive disorder is associated with decreased health-related quality of life, productivity (absenteeism/ presenteeism), and increased short- and long-term disability. Interventional studies have documented the salutary effects of chronic disease management on workforce disability.
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Notwithstanding the benefits offered by employee/health care service-based interventions, the majority of depressed employees continue to evince disability as measured by absenteeism/presenteeism and other measures. This latter observation provides the impetus for efforts that aim to elucidate separate factors that contribute to workforce impairment. It is a testable hypothesis that several chronic stress-sensitive medical conditions mediate (or moderate) the association between depressive symptom morbidity (and in some cases iatrogenic morbidity, e.g., weight gain from psychotropic medications) and functional impairment in the depressed employee (see Fig. 1). Sufficient evidence justifies screening for depression and associated medical conditions, ensuring that available resources can provide further evaluation and treatment. Greater attention and awareness of the association between depressive disorders and chronic medical disorders (e.g., overweight/obesity) is also warranted, given their bidirectional and deleterious effects on workforce functioning. Expanded public/private collaboration, parity in mental and physical health insurance coverage, and resource allocations proportionate to the prevalence of depression is warranted (Allen et al., 2010). Research needs to continue to unravel work-related epidemiology and etiology of depression, with a focus on primary, secondary, and tertiary prevention, the role of occupational and environmental medicine as part of integrative care paradigms, and the development of business models justifying interventions for workplace depression (Caruso, 2008). Conflict of interests Dr. McIntyre and Dr. Taylor each received an honorarium for writing this manuscript. There was no interference from the sponsor (Bristol-Myers Squibb; BMS), which was not involved in the collection, analysis and interpretation of data, or in manuscript preparation. Dr. McIntyre has participated on advisory boards, and/or in, continuing education activities for numerous pharmaceutical companies, including Astra Zeneca, Bristol-Myers Squibb, Eli Lilly, GlaxoSmithKline, Janssen-Ortho, Lundbeck, Organon, Pfizer, Wyeth. Dr. Taylor has participated on advisory boards, and or in, continuing education activities for: Astra Zeneca, Bristol-Myers Squibb, Eli Lilly, GlaxoSmithKline, JanssenOrtho, Wyeth. The authors have indicated that there are no other conflicts of interest regarding the content of this article. References Akincigil, A., Bowblis, J.R., Levin, C., Walkup, J.T., Jan, S., Crystal S., 2007. Adherence to antidepressant treatment among privately insured patients diagnosed with depression. Med. Care. 45(4), 363–369. Allen, H., Hyworon, Z., Colombi, A., 2010. Using self-reports of symptom severity to measure and manage workplace depression. J. Occup. Environ. Med. 52(4), 363–374. Aronsson, G., Gustafsson, K., 2005. Sickness presenteeism: prevalence, attendance-pressure factors, and an outline of a model for research. J. Occup. Environ. Med. 47(9), 958–966. Bergstrom, G., Bodin, L., Hagberg, J., Aronsson, G. Josephson, M., 2009. Sickness presenteeism today, sickness absenteeism tomorrow? A prospective study on sickness presenteeism and future sickness absenteeism. J. Occup. Environ. Med. 51(6), 629–638. Birnbaum, H.G., Ben-Hamadi, R., Kelley, D., Hsieh, M., Seal, B., Kantor, E., Cremieux, P.Y., Greenberg, P.E., 2010a. Assessing the relationship between
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Journal of Affective Disorders j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / j a d
Depression in the workforce: the intermediary effect of medical comorbidity Roger S. McIntyrea,b,c,d, *, Samantha Liauwc,e , Valerie H. Taylorf a Department
of Psychiatry, University of Toronto, Toronto, ON, Canada of Pharmacology, University of Toronto, Toronto, ON, Canada Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada d Institute of Medical Science, University of Toronto, Toronto, ON, Canada e McGill University, Montreal, QC, Canada f Department of Psychiatry, McMaster University, ON, Canada b Department c
article info
abstract
Keywords: Workforce disability Depression Medical comorbidity Obesity Diabetes Cardiovascular disease
Background: It is amply documented that mood disorders adversely affect job satisfaction, workforce productivity, and absenteeism/presenteeism. It is also well documented that mood disorders are an independent risk factor for several chronic medical disorders (e.g., obesity, diabetes mellitus, cardiovascular disease). Emerging evidence indicates that the workforce dysfunction associated with depression is partially mediated by medical comorbidity. Methods: We conducted a PubMed search of all English-language articles published between 2005 and July 2009 with the following search terms: major depressive disorder and depression, cross-referenced with work productivity, disability, economic cost, absenteeism, presenteeism, and medical comorbidity. Articles selected for review were based on adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality. Results: Mood disorders are the most impairing condition amongst working adults. It is estimated that approximately 35–50% of employees with depression will take short-term disability leave at some point during their job tenure. Moreover, 15–20% of the workforce will receive short-term disability benefits during any given year; the annual income of individuals affected by depression is reduced by approximately 10% when compared to unaffected employees. Chronic stress-sensitive conditions independently contribute to workforce maladjustment and associated disability. The mood disorder population is differentially affected by several stress-related medical conditions resulting in greater impairment in the workforce. Conclusion: Disability modelling in the depressed employee has emphasized the complex interrelationship between depressive symptoms, workforce stress, and consequent disability. A more refined model must include the effects of chronic medical conditions as a powerful mediator and/or moderator of workforce impairment. Multidisciplinary interventions have been demonstrated to reduce, but not eliminate workforce disability related to depression, underscoring the need for elucidating other modifiable factors. Screening, treatment, and prevention initiatives need to target chronic medical conditions in depressed employees in order to reduce overall workforce disability. © 2010 Elsevier B.V. All rights reserved.
1. Introduction Major depressive disorder is a highly prevalent chronic condition estimated to affect approximately 10–16% of individuals at some time in their life (Kessler et al., 2003). It * Corresponding author. Department of Psychiatry, University of Toronto. 399 Bathurst Street, Toronto, ON, Canada, M5T 2S8. Tel.: +1 416 603 5279. E-mail address: [email protected] (R.S. McIntyre). 0165-0327/$ – see front matter © 2010 Elsevier B.V. All rights reserved..
has been further reported that 15.7% of employed individuals (19.5% of women, 11.4% of men) met lifetime criteria for major depressive disorder and that 8.6% (10.2% of women, 5.9% of men) met 12-month criteria (Marcotte et al., 1999). The burden of illness attributable to depression is staggering, with projections that depression will be the second leading cause of disability-adjusted life years worldwide by the year 2020 (Murray and Lopez, 1997a; Wells et al., 1989).
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Greenberg et al. (2003) estimated that the annual cost of depression in 2000 was $83.1 billion. This estimate represents a 7% increase (from $77.4 billion) after adjusting for inflation when compared to an estimate a decade earlier (Greenberg et al., 1993). Comparative cost-of-illness studies have also reported that mood disorders, and their associated comorbidity, are the most costly conditions to employers (Druss et al., 2001, McIntyre et al., 2008). Moreover, population-based estimates of illness-associated morbidity have reported that neuropsychiatric illness accounts for approximately 15% of overall disability-adjusted life years in the general population (Murray and Lopez, 1997b). The majority of costs associated with major depressive disorder are indirect, reflecting psychosocial impairment and decreased workforce productivity (Birnbaum et al., 2010b). Underdetection, delay in diagnosis, misdiagnosis, guidelinediscordant care, and insufficiently applied treatment interventions remain modifiable deficiencies that account for a disproportionate number of days lost to work due to presenteeism and/or absenteeism (Wang et al., 2007). In addition to the economic consequences, depression-related workforce impairment has a deleterious effect on identity, social participation, and measures of physical and mental well being (Lauber and Bowen, 2010). During the past decade, many commentators have pressed the point that national and regional economies have shifted from primary industry to “human capital” or the “knowledge economy” (Birnbaum et al., 2010a). Major depressive disorder and related “stress conditions” (e.g., burnout) are the most common causes of decreased educational attainment and workforce performance in developed economies. Against this background, timely detection, diagnosis, treatment, and management of mood disorders in the working population has medical, economic, political, and social implications. This paper reviews the topic of depressive disorders and their impact on workforce productivity. It is not meant to be a comprehensive review of the topic, as this has been amply reviewed elsewhere (Hirschfeld et al., 2000, Lerner and Henke, 2008; Simon, 2003), but rather a succinct review with a particular emphasis on the hazardous effects of comorbid medical conditions in depressed employees and its intermediary effect on decreased workforce productivity. 2. Methods We conducted a PubMed search of all English-language articles published between 1966 and June 2010 with the following search terms: major depressive disorder and depression, cross-referenced with work productivity, disability, economic cost, absenteeism, presenteeism, and medical comorbidity. Articles selected for review were based on adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality. 3. Results Several original studies, reviews, and meta-analyses have addressed the impact of depression on workforce adjustment, attendance, absenteeism, presenteeism, short- and long-term disability, job strain, satisfaction, and performance
(Kessler et al., 1999). The results of these endeavours have been published and comprehensively reviewed elsewhere (Katon, 2009; Lerner et al., 2004; Mino et al., 2006; Simon et al., 2000; Simon, 2003; Williams and Schouten, 2008). Herein, we highlight several key findings. Kessler et al. (2006) reported that major depressive disorder results in 27.2 annualized lost workdays amongst respondents in the National Comorbidity Survey-Replication (NCS-R). A separate report by Kessler and colleagues (1999) concluded that while 17–21% of the workforce experiences short-term disability during any given year, 37–48% of workers with depression take short-term disability leave at some time during their job tenure (Goldberg and Steury, 2001). McIntyre et al. (2008), using data from the Canadian Community Health Survey (CCHS) reported that the annual income amongst adults 18 or older with major depressive disorder was approximately 10% lower when compared to adults without a lifetime history of a psychiatric disorder ($36 800 vs. $40 300). Moreover, individuals with depression had a higher risk of experiencing at least one mental health disability day within the past two weeks when compared to individuals without a mood disorder. Moreover, the odds of reporting satisfactory job security were much lower in individuals with major depressive disorder when compared to the general population (McIntyre et al., 2008). In addition to affecting a proband with depression, the functional consequences of depression extend to other family members and caregivers. This “ripple effect” is also apparent in terms of the impact of depression on a family’s socioeconomic status/attainment and subsequent illness vulnerability (i.e., caregiver burnout that accompanies mental illness can result in increased vulnerability for incident mental illness and decreased productivity in the caregiver) (Steele et al., 2010). Moreover, work-related financial stressors have been identified as a susceptibility factor to pediatric depression (Goodman et al., 2003). 3.1. Risk factors for workforce impairment In 1908, Robert Yerkes and John Dodson described an inverted U-shaped curve characterizing the relationship between stress and performance (Couser, 2008). Burnout in the workforce is frequently the result of unremitting, uncontrolled and excessive stressors perceived by the individual (e.g., the Job Strain Model, Demand-Control Model) (Virtanen et al., 2007). An extensive body of literature has documented the adverse effects of stress on job strain as a non-specific risk factor for adverse coping, depressive symptoms and episodes, antidepressant utilization, and early retirement (Bonde, 2008; Virtanen et al., 2007). Specific factors mediating this association include high job demand and low decision latitude and social support (emotional and instrumental) (Stoetzer et al., 2009). Moreover, serious conflict, exclusion by superiors, and exclusion by coworkers have been specifically associated with increased psychological distress and/or depression in the workforce (the odds ratios for these variables have ranged from 1.2 to 2.3, underscoring their salience). Intuitively, stressors within and outside of the workforce independently contribute to the risk of developing major depression. Despite this axiomatic notion, relatively few
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studies have evaluated whether the work environment interacts with psychosocial factors outside of the workplace as a mediating factor conferring an increased risk of major depression. Notwithstanding, a recently published population-based study reported that job strain, chronic stress, negative life events, and childhood traumatic events were all important risk factors for developing depressive episodes. The risk of developing depression increased in a dose-response pattern as a function of number of stressors. Nonetheless, psychosocial stressors within the job environment did not interact with factors outside of the workplace in relation to the risk of depression (Wang and Schmitz, 2010). A population-based Canadian study reported that specific subcomponents of work stress and depression differed between men and women. High job strain, low levels of social support in the workplace, low job security, and increased psychological demands were associated with major depressive episodes among men. Among women, lower levels of social support and lack of decision authority were associated with major depressive episodes. Low levels of skill discretion were inversely associated with major depressive episodes among women (Blackmore et al., 2007). A separate study on a large cohort of employees (n = 4133) in a Danish workforce setting analyzed the impact of psychosocial work characteristics on the incidence of depressive symptoms as part of a 5-year prospective study (Rugulies et al., 2006). It was concluded that among women, low influence at work demonstrated a dose-response relationship with risk of severe depressive symptoms; amongst men, neither influence at work, nor social support from supervisors was associated with depressive symptoms. Job insecurity, however, was predictive of depression in the male subpopulation. Social capital refers to the relationship between an individual and groups of people, and is proposed as a protective factor for mental health (Kouvonen et al., 2008). Amongst individuals employed in the public sector, it is reported that low self-reported social capital was associated with a greater odds of being prescribed antidepressant medication and/or receiving a diagnosis of depression (Kouvonen et al., 2008). Social capital has been divided into both vertical and horizontal components. Vertical social capital refers to norms of respect and networks of trusting relations between people who are interacting across explicit formal or institutionalized power or authority gradients in society (Oksanen et al., 2010). The horizontal component refers to relations of trust and reciprocity between individuals and groups at the same hierarchical level (Oksanen et al., 2010). Oksanen et al., evaluated whether or not vertical and horizontal social capital in the workforce differentially predicted depression in a large cohort (n = 25 763) of Finnish public sector workers. They reported that employees with either low vertical or horizontal social capital were 30–50% more likely to be diagnosed as either having depression or to start antidepressant treatment than their counterparts with high social capital. Presenteeism is often used interchangeably with “sickness presenteeism” and “presence”, referring to an employee attending work despite suboptimal performance. It has been
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reported that 63–83% of employees report having gone to work despite illness on at least one occasion during the previous year (Bergstrom et al., 2009). Sickness presenteeism has been identified as a risk factor for absenteeism in both the public and private sector for both sexes (Bergstrom et al., 2009). A dose-response gradient is implicated insofar as the number of sickness presenteeism episodes increases the likelihood of absenteeism. These results suggest that interventions that are intended to decrease sickness absence may lead to an increase in sickness presenteeism, with subsequently absenteeism due to sick leave in the long run (Bergstrom et al., 2009). Taken together, the foregoing observations indicate that in some cases sick leave may be preferred as a way of minimizing overall compromised workplace productivity. Presenteeism has been consistently identified as accounting for the majority of economic cost due to loss productivity of depression. As presenteeism is a “hidden-cost of depression” there is a need to identify a clinically meaningful and sensitive measure of this construct. Scales evaluating presenteeism include, but are not limited to, the Work Limitations Questionnaire and the Stanford Presenteeism Scale (Koopman et al., 2002; Lerner et al., 2004; Sanderson et al., 2007). Preliminary studies also indicate that presenteeism may be a stronger correlate of depression and anxiety than is absenteeism (Aronsson and Gustafsson, 2005). It should be highlighted that presenteeism is not always an undesirable outcome in an individual with depression in the workforce as the social support and structure as well as financial advantages of remaining in the workforce may be preferred to short- and long-term disability wherein there is a divorcing of the individual from possible psychosocial and financial gains of the workforce (Sanderson et al., 2007). These associations need to be addressed on an individual basis, evaluating which approach (i.e., prescribed disability leave or presenteeism) will ultimately provide the optimal outcome for the employee. 3.2. Comorbidity and workforce impairment in depressed populations Individuals with mood disorders are differentially affected by co-occurring psychiatric and medical conditions (Fleischhacker et al., 2008; McIntyre et al., 2007b; McIntyre, 2009). Accumulated evidence indicates that overall psychosocial impairment associated with mood disorders is mediated to a significant degree by co-occurring conditions (McIntyre et al., 2004; McIntyre et al., 2006a; McIntyre et al., 2007a; McIntyre et al., 2009). For example, attention deficit hyperactivity disorder and migraine headaches, conditions with reported high prevalence in individuals with mood disorders, are independently associated with impaired work performance (de Graaf et al., 2008; Kessler et al., 2010; McIntyre et al., 2006b). Concomitant medical comorbidity is also a significant contributor to both the employee and employer costs associated with depression. During the past few years, confronting the obesity epidemic has become a major policy focus globally. From a medical and public health perspective, rising rates of obesity are resulting in commensurate increases in the incidence of many chronic diseases, including type 2 diabetes, cardiovascular disease, and several
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Conventional Modelling Workforce Dysfunction
Mood Disorder
Proposed Modelling Mediational Model Mood Disorder
Workforce Dysfunction
Overweight/obesity Diabetes mellitus Cardiovascular disease Pain disorders Dementing disorders (mild cognitive impairment) Other chronic stress-sensitive medical disorders
Moderational Model Mood Disorder
Workforce Dysfunction Overweight/obesity Diabetes mellitus Cardiovascular disease Pain disorders Dementing disorders (mild cognitive impairment) Other chronic stress-sensitive medical disorders
Fig. 1. The association between mood disorders and workforce impairment: the meditational/moderational effects of chronic medical conditions.
types of cancer (Field et al., 2001). This has resulted in increased concern about the rising costs of heath care for this population, given that approximately 30% of the population is obese and the current obesity epidemic is expected to worsen in the next few years (Flegal et al., 2002). Moreover, rising obesity rates and its related complications have significant economic consequences for employers (Finkelstein et al., 2003). For example, it has been reported by a nationally representative 1000-person company, that overweight/obesity results in an increase in annual costs of $277 000. The reasons for the increased costs were categorized as indirect referring to absenteeism, disability, premature mortality, presenteeism, and workers’ compensation (Finkelstein et al., 2005; Fontaine et al., 2003; Trogdon et al., 2008) (Fig. 1). High rates of medical comorbidity also contribute to the costs associated with mood disorders, since individuals with mood disorders have higher rates of overweight/obesity, diabetes mellitus, hypertension, dyslipidemia, and cardiovascular disease when compared to the general population (Taylor et al., 2010). Emerging evidence also indicates that the functional impairment from obesity may be mediated in part by the presence of a co-occurring mental disorder (Bruffaerts et al., 2008). Several factors subserve the adverse outcome in the medically comorbid depressed individual including, but not limited to, the fact that persons with comorbid conditions often have a poorer treatment
response, a worse course of illness, and as described above, comorbid medical conditions are associated with independent effects on workforce productivity (Burton et al., 2008; Gates et al., 2008; Goetzel et al., 2010). 3.3. Interventional studies The burden and hazards posed by depression in the workforce provides the impetus for both screening interventions and the initiation of primary and secondary prevention strategies (see Gelenberg, 2010, for a review of depression screening and diagnostic tools, symptom surveillance measures and adverse event measurement scales. Many risk factors for depression are non-modifiable and are not the purview of the employer (e.g., low selfesteem, low self-efficacy, social stigma) (Couser, 2008). Nevertheless, factors such as social support, work demand, stress management, and interpersonal relations are possible targets for workforce prevention and treatment initiatives. Randomized controlled trials indicate that stress-management initiatives based on cognitive behavioural approaches carried out in the workforce significantly improve depressive symptoms. Stress management programs emphasize the importance of sufficient sleep and rest, regular exercise, maintaining good interpersonal relationships, challenging anxiety provoking and depressogenic thoughts, and muscle relaxation (Mino et al., 2006).
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Depression screening and enhanced care programs have been shown to significantly improve treatment and clinical outcomes amongst depressed individuals (Wang et al., 2007; Williams and Schouten, 2008). Historically, employer purchasers have been reluctant to invest in enhanced depression care programs in the workforce largely based on uncertainty on the return of investment (Wang et al., 2007). Wang et al., evaluated the impact of depression screening, vigorous outreach and care management of depressed workers employed by several large national companies (totalling approximately 150 000 workers). The intervention was a structured telephone program that assessed the needs for treatment, facilitated entry into in-person treatment, monitored and supported treatment adherence, and provided a structured psychotherapeutic intervention by telephone. Depression severity was evaluated with the Quick Inventory for Depressive Symptoms Self Report (QIDS-SR), www.ids-qids.org/, while work performance was evaluated with the WHO Health and Productivity Questionnaire (HPQ), www.hcp.med.harvard.edu/hpq/. The HPQ assesses four dimensions of work functioning: work hours, job performance, job turnover, and critical workforce incidence. After 6 and 12 months, the intervention group had significantly lower QIDS-SR scores, significantly higher job retention, and more hours worked among the employed than the usual care subjects. The increase in number of hours worked was equivalent to an annualized effect of approximately two and a half weeks of work (Wang et al., 2007). Early identification of problematic interpersonal relationships may also diminish the risk of employees developing adverse stress responses in the workforce (Stoetzer et al., 2009). The Agency for Healthcare Research and Quality (AHRQ) has developed the Healthcare Effectiveness Data and Information Set (HEDIS) treatment guidelines to measure antidepressant management specifying an 84-day acute phase as well as an overall 180-day continuation treatment phase (Birnbaum et al., 2010a). Adherence to antidepressants as measured by the HEDIS among privately insured patients with depression reported that 51% of patients adhered to treatment through the acute phase and 42% maintained treatment throughout the continuation phase (Akincigil et al., 2007). The high rate of discordance with guideline recommended care has also been reported in populationbased studies (Kessler et al., 2008). Others have reported that non-adherence to HEDIS treatment guidelines are more likely to receive short-term disability claims (Burton et al., 2007). Birnbaum et al., evaluated economic outcomes associated with compliance including both direct and indirect costs, by using data from two U.S. employers’ privately insured medical and prescription administrative claims databases (2004–2006). Among antidepressant users, medical costs were not statistically different for compliant versus noncompliant patients. Medication costs were higher for compliant patients due to increased antidepressant costs. Absenteeism rates were lower for compliant patients with antidepressant use ($3857 vs. $4907; p = 0.041) and among depressed patients ($3976 vs. $5899; p = 0.047), presenteeism costs were higher for depressed compliant patients ($19 170 vs. $15 829; p = 0.011) (Birnbaum et al., 2010a,b). Notwithstanding the lower absenteeism costs, the
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overall medical costs were not lower in the compliant patients. A Canadian study evaluated whether guideline-concordant antidepressant prescription was associated with improved disability outcomes and the relationship between guidelineconcordant antidepressant use and length of disability (Dewa et al., 2003). It was reported that workers using recommended first-line agents (and doses) were significantly more likely to return to work rather than claim long-term disability benefits or leave their employment. It was also reported that early intervention was significantly associated with a shortened disability episode among employees who had at least one antidepressant claim indicating that early intervention was associated with a reduction in disability of about three weeks (Dewa et al., 2003). The costs of medication treatment need to be weighed against the risks conferred by the side effects of therapy, with consideration given to the types of treatments prescribed (Kennedy et al., 2009). Endeavors (e.g., enhanced awareness campaigns, healthy lifestyle program access) that aim to minimize the iatrogenic risk for comorbid physical illness are exigently needed. Other interventional opportunities for individuals with mental illness in the workforce are destigmatization efforts and improved access (facilitated by employment assistance programs) to appropriate mental health services. The implementation and evaluation of these programs is still largely unexplored but should include a provision of basic information about symptoms, course of illness and treatment options, and involve active open communication between employee, employer, health care provider and other involved third parties (Laxman et al., 2008). The effect of workplace health promotion and “stressmanagement programs” (some of which are telephonebased and/or computer-based) on the risk of depression and anxiety has been extensively reviewed elsewhere (Grime, 2004, Martin et al., 2009; Zivin et al., 2009). Overall, results indicate that small, yet positive, effects of such interventions on the symptoms of depression are observed. Inconsistent effects on composite mental health measures have also been reported (Richardson and Rothstein, 2008; van der Klink et al., 2001). Several studies utilizing disparate designs (e.g., randomization, economic simulation) across populationbased, clinical, and workplace settings have reported a positive return on investment for disease management programs that target multiple chronic conditions, including depression (Goetzel et al., 2005; Lo Sasso et al., 2006). This finding is mirrored by results of a recent study by the Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion that reported that low-cost policy or environmental change interventions in worksites are more likely to be cost saving with robust improvement in employee wellness (Trogdon et al., 2009). 4. Conclusion Major depressive disorder is associated with decreased health-related quality of life, productivity (absenteeism/ presenteeism), and increased short- and long-term disability. Interventional studies have documented the salutary effects of chronic disease management on workforce disability.
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Notwithstanding the benefits offered by employee/health care service-based interventions, the majority of depressed employees continue to evince disability as measured by absenteeism/presenteeism and other measures. This latter observation provides the impetus for efforts that aim to elucidate separate factors that contribute to workforce impairment. It is a testable hypothesis that several chronic stress-sensitive medical conditions mediate (or moderate) the association between depressive symptom morbidity (and in some cases iatrogenic morbidity, e.g., weight gain from psychotropic medications) and functional impairment in the depressed employee (see Fig. 1). Sufficient evidence justifies screening for depression and associated medical conditions, ensuring that available resources can provide further evaluation and treatment. Greater attention and awareness of the association between depressive disorders and chronic medical disorders (e.g., overweight/obesity) is also warranted, given their bidirectional and deleterious effects on workforce functioning. Expanded public/private collaboration, parity in mental and physical health insurance coverage, and resource allocations proportionate to the prevalence of depression is warranted (Allen et al., 2010). Research needs to continue to unravel work-related epidemiology and etiology of depression, with a focus on primary, secondary, and tertiary prevention, the role of occupational and environmental medicine as part of integrative care paradigms, and the development of business models justifying interventions for workplace depression (Caruso, 2008). Conflict of interests Dr. McIntyre and Dr. Taylor each received an honorarium for writing this manuscript. There was no interference from the sponsor (Bristol-Myers Squibb; BMS), which was not involved in the collection, analysis and interpretation of data, or in manuscript preparation. Dr. McIntyre has participated on advisory boards, and/or in, continuing education activities for numerous pharmaceutical companies, including Astra Zeneca, Bristol-Myers Squibb, Eli Lilly, GlaxoSmithKline, Janssen-Ortho, Lundbeck, Organon, Pfizer, Wyeth. Dr. Taylor has participated on advisory boards, and or in, continuing education activities for: Astra Zeneca, Bristol-Myers Squibb, Eli Lilly, GlaxoSmithKline, JanssenOrtho, Wyeth. The authors have indicated that there are no other conflicts of interest regarding the content of this article. References Akincigil, A., Bowblis, J.R., Levin, C., Walkup, J.T., Jan, S., Crystal S., 2007. Adherence to antidepressant treatment among privately insured patients diagnosed with depression. Med. Care. 45(4), 363–369. Allen, H., Hyworon, Z., Colombi, A., 2010. Using self-reports of symptom severity to measure and manage workplace depression. J. Occup. Environ. Med. 52(4), 363–374. Aronsson, G., Gustafsson, K., 2005. Sickness presenteeism: prevalence, attendance-pressure factors, and an outline of a model for research. J. Occup. Environ. Med. 47(9), 958–966. Bergstrom, G., Bodin, L., Hagberg, J., Aronsson, G. Josephson, M., 2009. Sickness presenteeism today, sickness absenteeism tomorrow? A prospective study on sickness presenteeism and future sickness absenteeism. J. Occup. Environ. Med. 51(6), 629–638. Birnbaum, H.G., Ben-Hamadi, R., Kelley, D., Hsieh, M., Seal, B., Kantor, E., Cremieux, P.Y., Greenberg, P.E., 2010a. Assessing the relationship between
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