Association of Mood, Anxiety, and Substance Use Disorders With Occupational Status and Disability in a Community Sample

The variable describing harmful alcohol use that was derived for use in this analysis was not associated with any of the measures of workforce or functional status. This was true both for the crude estimates and for the adjusted estimates from the logistic regression analysis. Therefore, this variable was removed from the subsequent analyses. The estimates presented here include participants in the group without disorders.

As described above, the component of the analysis concerned with absence from work was restricted to 27,332 members of the original survey sample (N=36,984) between the ages of 18 and 64 who answered the occupational status and disability questions. Overall, 7,016 persons (23.1%) (CI=22.3%–23.8%) reported that during the preceding week they were not at a job or were permanently unable to work. Among 23,859 persons without a mood disorder, anxiety disorder, or substance dependence, 22.2% reported not working in the week preceding the interview. A higher proportion of persons with a mood or anxiety disorder reported not working ( Table 1 ). Among those with mood disorders alone, 27.1% (CI=23.5%–30.7%) were not working. A similar proportion was seen among persons with anxiety disorders. Unlike persons with mood or anxiety disorders, persons with substance dependence did not have an elevated frequency of nonworking status according to the unadjusted analysis. These patterns were fairly consistently observed in various age-sex categories ( Table 1 ), with the possible exception of women with mood disorders alone, for whom the frequency resembled that of persons without a disorder. Also, the association appeared to be weaker after stratification for income, probably because of a close correlation between income and working status.

The frequency of nonworking status among persons with mood disorders was highest in the 46 to 64 age group, among those who were unmarried, and among those with personal incomes less than $20,000 per year. Also of note, the frequency of nonworking was higher for women.

Whereas Table 1 reports the frequency of nonworking status during the week preceding the interview, Table 2 presents the proportions that reported not working during the preceding week for reasons of "own illness or disability." Although overall 23.1% did not work at a job or business over the past week, only 1,110 (3.5%) reported that they had done so because of "illness or disability." However, the pattern remained constant in the sense that mood or anxiety disorders were consistently associated with not working because of illness or disability, whereas substance dependence and harmful alcohol use were not. A strong association of mood and anxiety disorders with not working as a result of illness or disability was observed for both men and women. It was not possible to estimate several of the frequencies for substance dependence in Table 2 and Table 3 because of sample size constraints, so these columns are not included in these tables.

Both Tables 1 and 2 include a column for persons reporting more than one disorder. Unexpectedly, the frequency of not working as a result of illness or disability for comorbid disorders was similar to that observed for mood disorders.

Table 3 presents the proportion of the sample reporting at least one disability day (that is, reduced activities or days spent in bed during the two weeks preceding the interview) as a result of mental health problems or substance abuse. Here, the pattern of association was different than that for not working during the preceding week. The main difference was that persons with substance dependence had an elevated frequency of reporting one or more disability day (24 persons, or 2.6%, CI=1.3%–3.8%), compared with persons with no disorder (.4%, CI=.3%–.5%). Less than 1% of persons with no disorder reported having disability or sick days.

In the analysis that was based on disability days, the impact of comorbidity was evident. At least 12% of persons with more than one disorder reported a disability or sick day in the past 14 days. This rate is higher than the rates for mood disorders alone (6.8%) or anxiety disorders alone (2.6%). The rate for substance dependence was equivalent to that for anxiety disorders. The CIs suggest that the elevated frequencies in these groups cannot be accounted for by chance.

In order to extend and integrate the results presented in the tables, logistic regression was used. A specific concern was whether an association of mood and anxiety disorders would persist after adjustment for other factors. After adjustment for self-reported chronic medical conditions, age, sex, education level, and marital status, having a mood or anxiety disorder was strongly associated with not working as a result of illness or disability during the week preceding the interview. There was an association with mood and anxiety disorders (OR=2.3, CI=1.8–2.9) and with being female (OR=3.1, CI=2.6–3.7), but there was also an interaction of mood or anxiety disorder and female (OR=.8, CI=.6–.9), indicating that although the association of mood and anxiety disorders with not working as a result of illness or disability was strong among both men and women (as initially suggested by data in Table 2 ), the association among women was slightly smaller than the multiplicative risks associated with the two factors.

With adjustment for other variables in the model, an association with substance dependence emerged, although it remained weaker than that for mood and anxiety disorders (adjusted OR=1.4, CI=1.0–1.9). The CIs for this estimate include 1.0 because of rounding, but the association was significant (p=.03 for the Wald test). A similar logistic regression model for disability days confirmed the impressions gained from the stratified analysis: both the combined mood and anxiety disorder group and substance dependence were associated with disability or bed days related to mental health, the former more strongly than the latter. The adjusted OR for the combined mood or anxiety disorder category was 13.0 (CI=8.8–19.2), and for substance dependence it was 2.5 (CI=1.4–4.3).

The logistic regression for not working as a result of illness or disability was complex because of the presence of three significant interactions: female by mood or anxiety disorder, female by chronic medical condition, and age by chronic medical condition. There were no significant interactions in the model for disability or sick days, so that the main effects of a variety of predictors can be reported: chronic conditions (OR=2.6, CI=1.5–4.6), less than secondary-level education (OR=1.5, CI=1.1–2.2), single as marital status (OR=1.9, CI=1.3–3.0), and widowed, separated, or divorced as marital status (OR=1.6, CI=1.0–2.4). Age was included in these models as a continuous variable and was also associated with disability days.

In this study we examined the association between mental disorders and various measures of nonparticipation in work and more general impairment in functioning. The results identified a consistent pattern, irrespective of the measure of functional impairment employed: both mood and anxiety disorders and substance dependence were associated with disability and impaired functioning. These findings are consistent with prior research on both U.S. and Canadian samples ( 3, 4, 5, 8 ). In contrast to Parikh and colleagues ( 14 ), who found that major depression increased the risk of sick days in the past month by a factor of three, we observed that persons with a 12-month diagnosis of a mood or anxiety disorder were approximately 13 times more likely than persons without a mood or anxiety disorder to report at least one disability day in the past two weeks. The higher OR found in the study presented here may be due to statistical adjustment for demographic and clinical factors. It could also follow from the fact that our study focused on disability as a result of mental health or substance use problems, whereas the Parikh study included all reasons for disability.

When nonworking status as a broad indicator of disability was used, our findings are consistent with those of Ettner and colleagues ( 6 ). In their analysis lower rates of employment were independently associated with major depression and substance use disorder. Our findings indicate a stronger association between mood and anxiety disorders and nonworking status and disability than the association with substance disorder, but the lack of interactions in the models suggests independent effects. The stronger association of mood and anxiety disorders with employment rates may be due to characteristics of the conditions themselves. Alternatively, the CCHS-1.2 may have inadvertently selected "higher functioning" substance abusers who manage to retain employment despite having to take more days off because of their disorder. Highly transient, chronically unemployed persons with substance dependence (for example, homeless individuals) are not represented in a household survey such as the CCHS-1.2. It should be noted that our category for more than one disorder included a high proportion of cases with a mood or anxiety disorder comorbid with a substance use disorder. Unemployment rates in the group with more than one condition were significantly higher than the group with no disorders.

Because many other factors influence whether an individual has a job, employment rate is only a surrogate measure of disability. Fortunately, the CCHS-1.2 included more direct measures of functional disability. These results identified a consistent pattern, irrespective of the measure of functional impairment employed: both mood and anxiety disorders and substance dependence were associated with work-specific disability and impaired functioning when the analysis adjusted for relevant variables. In addition, the presence of more than one disorder was associated with the highest prevalence of functional impairment (as measured by the proportion reporting at least one disability day in the past two weeks), a finding consistent with Kessler and Frank ( 8 ), although their study focused exclusively on work-related impairment among employed persons.

In terms of demographic correlates, nonworking rates were consistently elevated in the 46- to 64-year-old group across most diagnostic groups. However, the rate within this age range was also higher in the group with no disorders, and one might imagine that some people in this age group took early retirement. Only the mood disorder and anxiety disorder groups had significantly higher nonworking rates than the group with no disorders in the upper age range. Persons in the lower income category consistently had higher rates of nonworking status, work-related disability, and functional impairment across all groups. Enhanced social vulnerability may also interact with the disorders' impact. In terms of gender trends, women who abused substances had a higher rate of not working in the preceding week than men in the same category. Additionally, among persons with anxiety disorder, women were more likely than men to attribute not working to their illness, compared with the group with no disorders. The higher rate of unemployment among women with no disorders in the sample is consistent with general labor-force trends in North America.

Isolating the effect of mental disorders on occupation status would require control for all potentially confounding variables. In this context, a confounding variable could be any determinant of occupational status with effects independent from those of mental disorders. In order to act as a confounder, such a variable would also need to be associated with mental disorder prevalence. Controlling for all such variables would require a more detailed data set and longitudinal data collection. As the goals of this study were descriptive, we have reported estimates that were adjusted for important descriptive variables because these models provide additional descriptive data. These should not be regarded as an attempt to isolate specific causal pathways.

The CCHS-1.2 version of the CIDI did not include a diagnostic module for assessing generalized anxiety disorder, obsessive-compulsive disorder, posttraumatic stress disorder, or dysthymic disorder. Furthermore, the illicit drug section of the CCHS-1.2 did not provide sufficient coverage of symptoms to define a category of harmful drug use. The absence of data on these conditions is a limitation of the survey, as is the absence of treatment data. The CCHS is also subject to the usual interpretive limitations resulting from its cross-sectional study design. Prominent among these is the lack of information provided by cross-sectional data about temporal relationships. It is possible, for example, that not working may contribute to the emergence of mental disorders, so the results cannot be interpreted in a unidirectional way: as evidence that mental disorders cause occupational disruption. Estimates deriving from cross-sectional data can also be impacted by factors such as prognosis and mortality. For example, if not working increases the duration of mood and anxiety disorder episodes, then an association could emerge in cross-sectional data even in the absence of a change in risk. Because treatment may mediate between a diagnosis and the resulting functional impairment, the lack of treatment data is another limitation of this analysis.

Several explanations may account for the stronger association observed for mood and anxiety disorders than for substance use disorder. The impairment resulting from mood and anxiety disorders tends to be highly persistent, whereas it is possible that substance-related impairment is more variable. For example, some of the impairment resulting from substance dependence may occur during intoxication or withdrawal, and some people may be able to manage their work schedules in compensatory ways—for example, by timing their substance use to avoid intoxication or withdrawal while they are at work. Also, because purchasing abused substances requires financial resources, a need for money may foster perseverance at work. People with substance dependence may not always attribute workplace difficulties to their substance use. Finally, if support for work absence resulting from illness is more available to people with mood and anxiety disorders, leaving the workplace because of one of these disorders may be more feasible for people with these disorders than for those with substance dependence.

Although the WMH-CIDI is considered a state-of-the-art structured diagnostic interview, it is subject to the limitations associated with fully structured interviews. The administration of this interview by lay interviewers cannot incorporate diagnostic judgment, and the interviewers cannot probe for more detail or deviate from the interview script in order to pursue additional information. In epidemiology, bias resulting from misclassification is often in the direction of no effect. It is possible that misclassification bias has caused some of the reported associations to appear weaker than they actually are.

Across all diagnostic groups a large discrepancy was revealed in the prevalence rates for being out of work in general and being out of work because of illness or disability. For example, 27.1% of individuals with a mood disorder had not worked in the previous week but only 13.0%, about half of these, attributed being out of work to illness or disability. This result is not necessarily surprising because functional impairment and disability have many determinants that may be interrelated and comprise separate elements of causal mechanisms. It should also be acknowledged that the group that was not working may include people who are not working for reasons other than impairment, such as being a student. For example, having a chronic medical condition may increase the risk of developing depression, and depression may detract from a person's capacity to cope with the challenges of functioning despite a chronic medical condition. The findings reported here draw attention to the need for detailed prospective occupational studies to clarify the underlying mechanisms. Identification of causal factors would facilitate the development of preventive strategies. However, cross-sectional data remain valuable for quantifying the extent of labor-force disruption that occurs among people with mental disorders.

Finally, in this study prevalence figures for mental disorders included persons with past-year diagnoses, whereas the employment questions focused on the previous week. It is possible that many individuals in the diagnostic groups were in a period of recovery from their disorder and did not attribute changes in their employment status to mental illness.

Although we have provided detailed interpretations of the CCHS-1.2 results, it should be acknowledged that the findings reported here are subject to limitations inherent in the design of most large mental health surveys, principally its cross-sectional nature and lack of full coverage of all potentially relevant variables. For example, it is possible that some of the associations will not be replicated by longitudinal studies and that the pattern of association may change with the inclusion of additional variables in the analysis. The results presented here will increase in credibility if they can be replicated in other populations and in studies with different methodological features.

Although physical disability is known to be an important determinant of labor-market outcomes, this article adds to the body of evidence describing the significant influence of mental and substance use disorders on work impairment. The adverse labor-force consequences support the economic argument in addition to the humane one for providing accessible treatment for mental and substance use disorders to members of the workforce.

This study was supported by grant ACC-65800 from the Canadian Institute of Health Research. The analysis was based on data collected by Statistics Canada, but the analysis and conclusions are those of the authors and not Statistics Canada.

The authors report no competing interests.

Dr. el-Guebaly is affiliated with the Department of Psychiatry, Dr. Currie is with the Department of Psychology and the Department of Community Medicine, Ms. Williams, Dr. Wang, Dr. Beck, and Dr. Patten are with the Department of Psychiatry and the Department of Community Medicine, and Dr. Maxwell is with the Department of Community Medicine, University of Calgary, Calgary, Alberta. Send correspondence to Dr. el-Guebaly at Calgary Health Region Foothills Hospital Addictions Program, 1403-29 St., NW, Calgary, Alberta, Canada T2N 2T9 (e-mail: [email protected]).