Publications used to support the parameters used in this model:

Berger ML, Howell R, Nicholson S, Sharda C (2003). Investing in healthy human capital. Journal of Occupational and Environmental Medicine, 45(12), 1213-1225.
Abstract: Although the value of human capital is not captured on company balance sheets, it may account for about half of the gap between a company's market value and book value. Yet, many companies do not focus comparable scrutiny on human capital management as compared with other large assets, nor do they systematically measure its output (ie, productivity). Methods are emerging to enable employers to assess productivity losses, including absenteeism and presenteeism, and to understand the associated costs (ie, direct medical costs, total productivity loss). This will permit employers to assess the value of programs to enhance health and productivity. We contend that the effective workforce is probably decreased by 5% to 10% because of health problems. We believe that employers who increase their investments in healthy human capital now will emerge tomorrow as the companies leading the gains in US productivity.

Berndt ER, Finkelstein SN, Greenberg PE, Howland RH, Keith A, Rush AJ, Russell J, Keller MB (1998). Workplace performance effects from chronic depression and its treatment. Journal of Health Economics, 17, 511-35.
Abstract: Utilizing data from a clinical trial and an econometric model incorporating the impact of a medical intervention and regression to the mean, we present evidence supporting the hypotheses that for chronically depressed individuals: (i) the level of perceived at-work performance is negatively related to the severity of depressive status; and (ii) a reduction in depressive severity improves the patient's perceived work performance. Improvement in work performance is rapid, with about two-thirds of the change occurring already by week four. Those patients having the greatest work improvement are those with both relatively low baseline work performance and the least severity of baseline depression.

Birnbaum HG, Greenberg PE, Barton M, Kessler RC, Rowland CR, Williamson TE (1999). Workplace burden of depression: A case study in social functioning using employer claims data. Drug Benefit Trends, 11(8):6.
Abstract: While the literature on the economics of depression and its treatment has burgeoned in recent years, little has been written from the perspective of an employer interested in comprehensively managing the overall burden of this illness in the workplace. Ideally, such an analysis would include assessment of the relationship between the direct costs of depression (including hospitalization, outpatient care, physician visits, and prescription drugs) and the indirect costs of illness in the workplace (including the value of missed work days for disability and sick time, reduced on-the-job productivity, and the search and training costs resulting from depression-induced turnover). This analysis measures the direct and indirect costs of major depression, using claims data from a Fortune 100 manufacturer.

Cantrell CR, Eaddy MT, Shah MB, Regan TS, Sokol MC. Methods for evaluating patient adherence to antidepressant therapy: a real-world comparison of adherence and economic outcomes. Med Care. 2006 Apr;44(4):300-3.
OBJECTIVE: The objective of this study was to differentiate between 3 measures of antidepressant adherence with regard to the number of patients deemed adherent to therapy and the association between adherence and resource utilization. DESIGN AND SETTING: The authors conducted a retrospective study of patients initiating selective serotonin reuptake inhibitor (SSRI) therapy for depression and/or anxiety between July 2001 and June 2002 in a large national managed care database. MAIN OUTCOME MEASURES: Rates of 6-month SSRI adherence were measured by 3 different metrics: length of therapy (LOT), medication possession ratio (MPR), and combined MPR/LOT. Differences in resource utilization for each adherence metric were measured for patients deemed as 1) adherent, 2) nonadherent, 3) therapy changers, and 4) dose titraters. RESULTS: There were 22,947 patients meeting study criteria. Although statistically different, 6-month adherence rates were numerically similar across all methods (LOT, 44.6%; MPR, 43.3%; and MPR/LOT, 42.9%, P < 0.001); approximately 57% of patients were nonadherent to therapy. Regardless of metric, the adherent cohort incurred the lowest yearly medical costs, followed by the nonadherent, titrate, and therapy change cohorts (P < 0.001 between adherent cohort and all other cohorts). The LOT method produced the greatest difference in yearly medical costs between adherent and nonadherent patients (Dollars 511) followed by MPR/LOT (Dollars 432) and MPR (Dollars 423). When antidepressant prescription costs were added to medical costs, patients requiring a therapy change and titrating therapy incurred higher costs than adherent patients, whereas nonadherent and adherent patients incurred similar costs. CONCLUSION: Regardless of adherence metric, approximately 43% of patients were adherent to antidepressant therapy, and adherent patients were associated with the lowest yearly medical costs.

Claxton AJ, Chawla AJ, Kennedy S (1999). Absenteeism among employees treated for depression. Journal of Occupational and Environmental Medicine, 41, 605-11.
Abstract: Depression-related costs include a relatively large share of indirect costs. We describe the impact of antidepressant treatment on absenteeism among workers diagnosed and treated for depression. Monthly absenteeism counts from employers were summed in the six months before and after the initiation of antidepressant therapy in 630 workers treated for depression with a tricyclic antidepressant or a selective serotonin reuptake inhibitor (fluoxetine, sertraline, paroxetine). Monthly mean absenteeism was compared using pairwise t tests. Absenteeism increased before antidepressant initiation and decreased after the treatment began for all antidepressant cohorts. Absenteeism in the selective serotonin reuptake inhibitor cohorts decreased at similar rates for four months but was higher in the paroxetine cohort in months five and six after the treatment initiation. Our data suggest that alternative treatments for depression may have differential impact on indirect costs, but further research is warranted.

Druss BG, Rosenheck RA, Sledge WH (2000). Health and disability costs of depressive illness in a major U.S. corporation. American Journal of Psychiatry, 157:8, 1274-1278.
Abstract: OBJECTIVE: Employers are playing an increasingly influential role in determining the scope and character of health coverage in the United States. This study compares the health and disability costs of depressive illness with those of four other chronic conditions among employees of a large U.S. corporation. METHOD: Data from the health and employee files of 15,153 employees of a major U.S. corporation who filed health claims in 1995 were examined. Analyses compared the mental health costs, medical costs, sick days, and total health and disability costs associated with depression and four other conditions: heart disease, diabetes, hypertension, and back problems. Regression models were used to control for demographic differences and job characteristics. RESULTS: Employees treated for depression incurred annual per capita health and disability costs of $5,415, significantly more than the cost for hypertension and comparable to the cost for the three other medical conditions. Employees with depressive illness plus any of the other conditions cost 1.7 times more than those with the comparison medical conditions alone. Depressive illness was associated with a mean of 9.86 annual sick days, significantly more than any of the other conditions. Depressed employees under the age of 40 years took 3.5 more annual sick days than those 40 years old or older. CONCLUSIONS: The cost of depression to employers, particularly the cost in lost work days, is as great or greater than the cost of many other common medical illnesses, and the combination of depressive and other common illnesses is particularly costly. The strong association between depressive illness and sick days in younger workers suggests that the impact of depression may increase as these workers age.

Dunlop DD, Manheim LM, Song J, Lyons JS, Chang RW. Incidence of disability among preretirement adults: the impact of depression. Am J Public Health. 2005 Nov;95(11):2003-8.
OBJECTIVES: We evaluated the effect of depression on risk, on the basis of standardized assessment, for developing activities of daily living (ADL) disability. METHODS: Depression-related risk on 2-year ADL disability is estimated from 6871 participants in a population-based national sample aged 54-65 years and free of baseline ADL disability. We evaluated the effects of factors amenable to clinical and public health intervention that may explain the relationship between depression and incident disability. RESULTS: The odds of ADL disability were 4.3 times greater for depressed adults than their non-depressed peers (95% confidence interval=3.1, 6.0). Among depressed adults, 18.7% of African Americans, 8.0% of Whites, and 7.8% of His-panics developed disability within 2 years. The attributable population fraction because of depression is 17.3% (95% confidence interval=11%, 24%). Concurrent health factors moderated depression-associated risk. CONCLUSIONS: Elevated risk of ADL disability onset because of depression, in a cohort whose medical costs will imminently be covered via Medicare, is attenuated by factors amenable to public health intervention. Prevention and/or public health/policy programs that lead to more accessible and effective mental health and medical care could reduce the development of ADL disability among depressed adults.

Dunner DL, Kwong WJ, Houser TL, Richard NE, Donahue RMJ, Kahn ZM (2001). Improved health-related quality of life and reduced productivity loss after treatment with bupropion sustained release: A study in patients with major depression. Journal of Clinical Psychiatry, 3(1), 10-16.
Abstract: Background: This open-label portion of a 2-phase study assessed the effects of the antidepressant bupropion sustained release (SR) on health-related quality of life (QOL) and workplace productivity in patients with major depression. Method: Patients (N = 816) with DSM-IV major depression were treated with bupropion SR, 300 mg/day, for eight weeks. The Clinical Global Impressions scale for Improvement of Illness (CGI-I) was completed at weekly clinic visits. At baseline and week 8, QOL and productivity were assessed. QOL was assessed using the Quality of Life in Depression Scale (QLDS). Results: QOL and productivity were significantly improved from baseline after eight weeks of treatment with bupropion SR. Mean QLDS scores were 18.98 and 10.36 at baseline and week 8, respectively (mean change = 8.62; p < .001). At week 8 compared with baseline, patients working at a paid job reported missing 1.58 fewer hours of work because of depression during the past seven days, being 14.6% more effective on the job, working at reduced effectiveness less often, and incurring 6.37 fewer hours of overall lost productivity (p < .001 each variable). Improvements in QOL and productivity were significantly (p < .001) greater in bupropion SR responders (i.e., those with CGI-I scores of "very much improved" or "much improved" during the last three weeks of open-label therapy) than in nonresponders. Conclusion: Effective treatment of major depression with bupropion SR for eight weeks is associated with improvements in QOL and reductions in lost workplace productivity. Patients who responded clinically to bupropion SR showed significantly greater improvements in these variables than those who did not respond.

Giller E Jr, Bialos D, Riddle MA, Waldo MC (1998). MAOI treatment response: multiaxial assessment. Journal of Affective Disorders, 14, 171-5.
Abstract: While studying the effectiveness of the MAOI isocarboxazid for the treatment of depression, we noted that many patients experienced a reduction of symptoms without equivalent improvement in other areas of their lives. We evaluated four outcome areas: symptoms, work, family functioning and social functioning. After six weeks on medication, symptoms improved the most, significantly more so than the other three areas. For the group of patients who completed 24 weeks on medication, all four outcome areas were further improved compared to the 6-week levels, with the improvement in work functioning reaching statistical significance. We conclude that the assessment of treatment outcome is more complex than the simple measurement of symptom reduction, and that different outcome areas are likely to improve at different rates and to different extents.

Goetzel RZ, Anderson DR, Whitmer RW, Ozminkowski RJ, Dunn RL, Wasserman J, HERO Research Committee (1998). The relationship between modifiable health risks and health care expenditures. Journal of Occupational and Environmental Medicine, 40(10), 843-854.
Abstract: This investigation estimates the impact of ten modifiable health risk behaviors and measures and their impact on health care expenditures, controlling for other measured risk and demographic factors. Retrospective two-stage multivariate analyses, including logistic and linear regression models, were used to follow up 46,026 employees from six large health care purchasers for up to three years after they completed an initial health risk appraisal. These participants contributed 113,963 person-years of experience. Results show that employees at high risk for poor health outcomes had significantly higher expenditures than did subjects at lower risk in seven of ten risk categories: those who reported themselves as depressed (70% higher expenditures), at high stress (46%), with high blood glucose levels (35%), at extremely high or low body weight (21%), former (20%) and current (14%) tobacco users, with high blood pressure (12%), and with sedentary lifestyle (10%). These same risk factors were found to be associated with a higher likelihood of having extremely high (outlier) expenditures. Employees with multiple risk profiles for specific disease outcomes had higher expenditures than did those without these profiles for the following diseases: heart disease (228% higher expenditures), psychosocial problems (147%), and stroke (85%). Compared with prior studies, the results provide more precise estimates of the incremental medical expenditures associated with common modifiable risk factors after we controlled for multiple risk conditions and demographic confounders. The authors conclude that common modifiable health risks are associated with short-term increases in the likelihood of incurring health expenditures and in the magnitude of those expenditures.

Greenberg PE, Kessler RC, Birnbaum HG, Leong SA, Lowe SW, Berglund PA, Corey-Lisle PK (2003). The economic burden of depression in the United States: How did it change between 1990 and 2000? Journal of Clinical Psychiatry, 64:12, 1465-1475.
Abstract: BACKGROUND: The economic burden of depression was estimated to be 43.7 billion dollars in 1990. A subsequent study reported a cost burden of 52.9 billion dollars using revised prevalence data and a refined workplace cost estimation approach. The objective of the current report is to provide a 10-year update of these estimates using the same methodological framework. METHOD: Using a human capital approach, we developed prevalence-based estimates of three major cost categories: (1) direct costs, (2) mortality costs arising from depression-related suicides, and (3) costs associated with depression in the workplace. Cost-of-illness estimates from 1990 were updated to reflect the experience in 2000 using current epidemiologic data and publicly available population, wage, and cost information. RESULTS: Whereas the treatment rate of depression increased by over 50%, its economic burden rose by only 7%, going from 77.4 billion dollars in 1990 (inflation-adjusted dollars) to 83.1 billion dollars in 2000. Of the 2000 total, 26.1 billion dollars (31%) were direct medical costs, 5.4 billion dollars (7%) were suicide-related mortality costs, and 51.5 billion dollars (62%) were workplace costs. CONCLUSION: The economic burden of depression remained relatively stable between 1990 and 2000, despite a dramatic increase in the proportion of depression sufferers who received treatment. Future research will incorporate additional costs associated with depression sufferers, including the excess costs of their coexisting psychiatric and medical conditions and attention to the role of painful conditions as a driver of these costs.

Kessler RC, Greenberg PE, Mickelson KD, Meneades LM, Wang PS (2001). The effects of chronic medical conditions on work loss and work cutback. Journal of Occupational and Environmental Medicine, 43(3), 218-225.
Abstract: Although work performance has become an important outcome in cost-of-illness studies, little is known about the comparative effects of different commonly occurring chronic conditions on work impairment in general population samples. Such data are presented here from a large-scale, nationally representative general population survey. The data are from the MacArthur Foundation Midlife Development in the United States (MIDUS) survey, a nationally representative telephone-mail survey of 3,032 respondents in the age range of 25 to 74 years. The 2,074 survey respondents in the age range of 25 to 54 years are the focus of the current report. The data collection included a chronic-conditions checklist and questions about how many days out of the past 30 each respondent was either totally unable to work or perform normal activities because of health problems (work-loss days) or had to cut back on these activities because of health problems (work-cutback days). Regression analysis was used to estimate the effects of conditions on work impairments, controlling for sociodemographics. At least one illness-related work-loss or work-cutback day in the past 30 days was reported by 22.4% of respondents, with a monthly average of 6.7 such days among those with any work impairment. This is equivalent to an annualized national estimate of over 2.5 billion work-impairment days in the age range of the sample. Cancer is associated with by far the highest reported prevalence of any impairment (66.2%) and the highest conditional number of impairment days in the past 30 (16.4 days). Other conditions associated with high odds of any impairment include ulcers, major depression, and panic disorder, whereas other conditions associated with a large conditional number of impairment days include heart disease and high blood pressure. Comorbidities involving combinations of arthritis, ulcers, mental disorders, and substance dependence are associated with higher impairments than expected on the basis of an additive model. The effects of conditions do not differ systematically across subsamples defined on the basis of age, sex, education, or employment status. The enormous magnitude of the work impairment associated with chronic conditions and the economic advantages of interventions for ill workers that reduce work impairments should be factored into employer cost-benefit calculations of expanding health insurance coverage. Given the enormous work impairment associated with cancer and the fact that the vast majority of employed people who are diagnosed with cancer stay in the workforce through at least part of their course of treatment, interventions aimed at reducing the workplace costs of this illness should be a priority.

Kouzis AC & Eaton WW (1994). Emotional disability days: Prevalence and predictors. American Journal of Public Health, 84: 1304-1307.
Abstract: This study considered days missed from work or usual activities for emotional reasons associated with a range of specific psychopathologic disorders, psychosocial distress, and persons found to be asymptomatic. Analyses were performed with the presence or absence of emotional disability days as the dependent variable using logistic regression. The effects of specific mental disorders were compared with the effects of chronic physical conditions for labor force participants and for the total population. The odds ratio (and 95% confidence interval) for subjects with major depressive disorder was 27.8 (6.93, 108.96); for panic disorder, 21.1 (2.25, 198.44); and for schizophrenia, 17.8 (1.73, 182.99). Work-place adjustments for persons with psychopathology are encouraged.

Lim D, Sanderson K, Andrews G (2000). Lost productivity among full-time workers with mental disorders. The Journal of Mental Health Policy and Economics, 3: 139-146.
Abstract: Background: Few studies have systematically compared the relationship between lost work productivity (work impairment) and mental disorders using population surveys. Aims: (1) To identify the importance of individual mental disorders and disorder co-occurrences (comorbidity) as predictors of two measures of work impairment over the past month - work loss (number of days unable to perform usual activities) and work cutback (number of days where usual activities were restricted); (2) to examine whether different types of disorder have a greater impact on work impairment in some occupations than others; (3) to determine whether work impairment in those with a disorder is related to treatment seeking. Method: Data were based on full-time workers identified by the Australian National Survey of Mental Health and Well-Being, a household survey of mental disorders modeled on the US National Comorbidity Survey. Diagnoses were of one-month DSM-IV affective, anxiety and substance-related disorders. Screening instruments generated likely cases of ICD-10 personality disorders. The association of disorder types and their co-occurrences with work impairment was examined using multivariate linear regression. Odds ratios determined the significance of mental disorder prevalence across occupations, and planned contrasts were used to test for differences in work impairment across occupations within disorder types. The relationship between work impairment and treatment seeking was determined for each broad diagnostic group with t-tests. Results: Depression, generalized anxiety disorder, and personality disorders were predictive of work impairment after controlling for impairment due to physical disorders. Among pure and comorbid disorders, affective and comorbid anxiety-affective disorders respectively were associated with the greatest amount of work impairment. For all disorders, stronger associations were obtained for work cutback than for work loss. No relationship was found between type of occupation and the impact of different types of disorder on work impairment. Only 15% of people with any mental disorder had sought help in the past month. For any mental disorder, significantly greater work loss and work cutback was associated with treatment seeking, but comparisons within specific disorder types were not significant. Discussion: A substantial amount of lost productivity due to mental disorders comes from within the full-time working population. The greater impact of mental disorders on work cutback compared to work loss suggests that work cutback provides a more sensitive measure of work impairment in those with mental disorders. Work impairment was based on self-report only. While there is evidence for the reliability of self-assessed work loss days, no reliability or validity studies have been conducted for work cutback days. The low rates of treatment seeking are a major health issue for the workforce, particularly for affective and anxiety disorders, which are important predictors of lost productivity. Implications for health policies and further research: Future research should investigate the validity of work cutback, given its importance as a measure of lost productivity in people with mental disorders. Employers need to be aware of the extent to which mental disorders affect their employees so that effective work place interventions can take place. Treatment should be targeted at people with affective and anxiety disorders, particularly where they co-occur.

Liu C-F, Hedrick SC, Chaney EF, Heagerty P, Felker B, Hasenberg N, Fihn S, Katon W. Cost-effectiveness of collaborative care for depression in a primary care veteran population. Psychiatr Serv 2003; 54: 698-704.
OBJECTIVE: This study examined the incremental cost-effectiveness of a collaborative care intervention for depression compared with consult-liaison care. METHODS: A total of 354 patients in a Department of Veterans Affairs (VA) primary care clinic who met the criteria for major depression or dysthymia were randomly assigned to one of the two care models. Under the collaborative care model, a mental health team provided a treatment plan to primary care providers, telephoned patients to encourage adherence, reviewed treatment results, and suggested modifications. Outcomes were assessed at three and nine months by telephone interviews. Health care use and costs were also assessed. RESULTS: A significantly greater number of collaborative care patients were treated for depression and given prescriptions for antidepressants. The collaborative care patients experienced an average of 14.6 additional depression-free days over the nine months. The mean incremental cost of the intervention per patient was $237 US dollars for depression treatment and $519 US dollars for total outpatient costs. A majority of the additional expenditures were accounted for by the intervention. The incremental cost-effectiveness ratio was $24 US dollars per depression-free day for depression treatment costs and $33 US dollars for total outpatient cost. CONCLUSIONS: Better coordination and communication under collaborative care was associated with a greater number of patients being treated for depression and with moderate increases in days free of depression and in treatment cost. Additional resources are needed for effective collaborative care models for depression treatment in primary care.

Mintz J, Mintz LI, Arruda MJ, Hwang SS (1992). Treatments of depression and the functional capacity to work. Archives of General Psychiatry, 49, 761-8.
Abstract: This study evaluated the effects of antidepressants and psychotherapy on work impairment in depressed patients. Original databases from 10 published treatment studies were compiled and analyzed (N = 827). Functional work impairment was common at baseline, manifested by unemployment (11%) or on-the-job performance problems (absenteeism, decreased productivity, interpersonal problems, 44%). Generally, work outcomes were good when treatment was symptomatically effective, but the trajectories of work restoration and symptom remission were different, with work recovery appearing to take considerably longer. Relapse was an important determinant of long-term occupational outcome, particularly for seriously ill patients for whom relapse meant rehospitalization or other profound social disruption. Affective impairment was distinguished from functional impairment, with the former characterizing milder depression and the latter characterizing moderate to severe depression. Some methodological recommendations are discussed.

Robinson RL, Long SR, Chang S, Able S, Baser O, Obenchain RL, Swindle RW. Higher costs and therapeutic factors associated with adherence to NCQA HEDIS antidepressant medication management measures: analysis of administrative claims. J Manag Care Pharm. 2006 Jan-Feb;12(1):43-54.
OBJECTIVE: To determine if the type of antidepressant drug is related to adherence to National Committee for Quality Assurance (NCQA) Antidepressant Medication Management (AMM) quality measures and to assess the 6-month health care costs among newly diagnosed depressed patients. METHODS: The MarketScan Commercial Claims and Encounter database for medical and pharmacy claims from January 2001 to September 2004 was used to assess adherence to the 3 AMM quality-of-care measures. AMM measures include (a) acute phase, the percentage of eligible members who remained on antidepressant medication continuously for 3 months after the initial diagnosis as determined by at least 84 days supply of antidepressant drugs during the first 114 days following receipt of the index antidepressant; (b) continuation phase, the percentage of eligible members who remained on antidepressant medication continuously for the 6 months after the initial diagnosis as determined by at least 180 days supply of antidepressants during the first 214 days following receipt of the index antidepressant; and (c) practitioner contacts, the percentage of members who received at least 3 follow-up office visits or telephone contacts with health care providers, including at least 1 contact with a practitioner licensed to prescribe (may not necessarily be the prescriber of the antidepressant). A fourth measure, overall adherence, was added, if all 3 AMM measures were met. Multivariate regression models determined demographic, clinical (such as receipt of mental health specialty care, the Charlson Comorbidity Index score, and co-occurring bipolar or schizophrenia), and therapy-related factors associated with outcomes of adherence and costs (paid amounts for insurance-reimbursable health care services for inpatient admissions, emergency department services, outpatient services, and outpatient prescription drugs). Health care expenditures (both total and mental-health-specific costs) were measured for each patient for 6 months following the date of service for the index antidepressant. RESULTS: A total of 60,386 adult patients (10.7%) of 562,898 patients with a depression diagnosis met NCQA inclusion criteria in the AMM Technical Specifications (e.g., aged 18 years or older, newly diagnosed with depression and initiating antidepressant therapy, 365 days of continuous enrollment; patients were excluded if there were missing data on dose or quantity of index drug in pharmacy claims or initiated therapy on 2 or more antidepressants as the index medication, exclusion criteria not in the AMM Technical Specifications). Only 19% of patients achieved overall adherence. Rates for the 3 AMM measures were 39% for practitioner contacts, 65% for acute phase, and 44% for continuation phase. Receipt of mental health specialty care was the only factor that was positively associated with greater adherence on all 4 measures (overall measure: odds ratio [OR]=3.895, 95% confidence interval [CI], 3.72-4.07; acute OR=1.38, 95% CI, 1.33-1.43; continuation OR=1.46, 95% CI, 1.41-1.51; contacts OR=5.83, 95% CI, 5.62-6.06). Most patients were initiated on selective serotonin reuptake inhibitors (SSRIs, 69.5%), followed by venlafaxine (21.4%), tricyclic antidepressants (TCAs, 21.4%), bupropion (11.0%), and other antidepressants (e.g., mirtazapine, nefazadone, trazadone; 7.2%). Before adjustment for confounding factors, patients initiated on venlafaxine, TCAs, or other antidepressants had higher rates of adherence on the overall performance measure versus initiators on SSRIs, but the absolute differences were relatively small: 21.4% for venlafaxine and TCAs and 23.1% for other antidepressants versus 18.5% for SSRIs (P <<>0.001). Patients initiated on venlafaxine, TCAs, or other antidepressants were also more likely to receive care from a mental health specialist, 16.8%, 15.0%, and 54.8%, respectively, compared with SSRIs (13.0%, all P <<>0.001). Regression analysis showed that only venlafaxine had a higher OR (1.13; 95% CI, 1.05-1.22) compared with SSRIs for adherence on the overall measure. Initiating dose level was in the target range for 70.0% of all patients (24.9% were below target dose and 5.2% above target dose), and adherent patients on all 3 AMM measures were less likely than nonadherent patients (70.4% vs. 68.4%, P <<>0.001) to be initiated in the target dose range. After multivariate adjustment, the initiating dose (target vs. high) was a significant factor in explaining adherence to the overall measure (OR=1.26; 95% CI, 1.16- 1.37). Adherent patients had 6-month median unadjusted total health care expenses that were nearly 2 times higher compared with nonadherent patients ($5,169 vs. $2,734) and mental health expenditures that were nearly 3 times higher ($1,922 vs. $677). After adjustment, adherent patients compared with nonadherent patients incurred an additional $644 in mental health expenditures and $806 in overall health care expenditures in the 6 months following initiation of antidepressant therapy. CONCLUSIONS: Only 19% of depressed patients initiated on antidepressants met all 3 criteria set forth in the NCQA Health Plan Employer Data and Information Set (HEDIS) AMM quality-of-care performance measures. Receipt of mental health specialty care was the single factor most strongly associated with quality treatment by these measures. Type and dosage level of initial antidepressant was associated with adherence to the NCQA HEDIS AMM measures, but the absolute difference in rates of adherence were relatively small among types of antidepressants. Costs were higher for guideline-adherent individuals in the 6 months following treatment initiation. These analyses were limited to administrative claims that lack indicators of depression disease severity.

Rost K, Smith JL, Dickinson M. The effect of improving primary care depression management on employee absenteeism and productivity. A randomized trial. Med Care. 2004 Dec;42(12):1202-10.
OBJECTIVE: To test whether an intervention to improve primary care depression management significantly improves productivity at work and absenteeism over 2 years. SETTING AND SUBJECTS: Twelve community primary care practices recruiting depressed primary care patients identified in a previsit screening. RESEARCH DESIGN: Practices were stratified by depression treatment patterns before randomization to enhanced or usual care. After delivering brief training, enhanced care clinicians provided improved depression management over 24 months. The research team evaluated productivity and absenteeism at baseline, 6, 12, 18, and 24 months in 326 patients who reported full-or part-time work at one or more completed waves. RESULTS: Employed patients in the enhanced care condition reported 6.1% greater productivity and 22.8% less absenteeism over 2 years. Consistent with its impact on depression severity and emotional role functioning, intervention effects were more observable in consistently employed subjects where the intervention improved productivity by 8.2% over 2 years at an estimated annual value of US 1982 dollars per depressed full-time equivalent and reduced absenteeism by 28.4% or 12.3 days over 2 years at an estimated annual value of US 619 dollars per depressed full-time equivalent. CONCLUSIONS: This trial, which is the first to our knowledge to demonstrate that improving the quality of care for any chronic disease has positive consequences for productivity and absenteeism, encourages formal cost-benefit research to assess the potential return-on-investment employers of stable workforces can realize from using their purchasing power to encourage better depression treatment for their employees.

Schoenbaum M, Unutzer J, Sherbourne C et al. Cost-effectiveness of practice-initiated quality improvement for depression: results of a randomized controlled trial. JAMA 2001 September 19;286(11):1325-30.
CONTEXT: Depression is a leading cause of disability worldwide, but treatment rates in primary care are low. OBJECTIVE: To determine the cost-effectiveness from a societal perspective of 2 quality improvement (QI) interventions to improve treatment of depression in primary care and their effects on patient employment. DESIGN: Group-level randomized controlled trial conducted June 1996 to July 1999. SETTING: Forty-six primary care clinics in 6 community-based managed care organizations. PARTICIPANTS: One hundred eighty-one primary care clinicians and 1356 patients with positive screening results for current depression. INTERVENTIONS: Matched practices were randomly assigned to provide usual care (n = 443 patients) or to 1 of 2 QI interventions offering training to practice leaders and nurses, enhanced educational and assessment resources, and either nurses for medication follow-up (QI-meds; n = 424 patients) or trained local psychotherapists (QI-therapy; n = 489). Practices could flexibly implement the interventions, which did not assign type of treatment. MAIN OUTCOME MEASURES: Total health care costs, costs per quality-adjusted life-year (QALY), days with depression burden, and employment over 24 months, compared between usual care and the 2 interventions. RESULTS: Relative to usual care, average health care costs increased $419 (11%) in QI-meds (P =.35) and $485 (13%) in QI-therapy (P =.28); estimated costs per QALY gained were between $15 331 and $36 467 for QI-meds and $9478 and $21 478 for QI-therapy; and patients had 25 (P =.19) and 47 (P =.01) fewer days with depression burden and were employed 17.9 (P =.07) and 20.9 (P =.03) more days during the study period. CONCLUSIONS: Societal cost-effectiveness of practice-initiated QI efforts for depression is comparable with that of accepted medical interventions. The intervention effects on employment may be of particular interest to employers and other stakeholders.

Simon GE, Katon W, Rutter C, VonKorff M, Lin E, Robinson P, Bush T, Walker EA, Ludman E, Russo J (1998). Impact of improved depression treatment in primary care on daily functioning and disability. Psychological Medicine, 28, 693-701.
Abstract: Few data are available regarding the impact of improved depression treatment on daily functioning and disability. METHODS: In two studies of more intensive depression treatment in primary care, patients initiating antidepressant treatment were randomly assigned to either usual care or to a collaborative management program including patient education, on-site mental health treatment, adjustment of antidepressant medication, behavioral activation and monitoring of medication adherence. Assessments at baseline as well as 4 and 7 months included several measures of impairment, daily functioning and disability: self-rated overall health, number of bodily pains, number of somatization symptoms, changes in work due to health, reduction in leisure activities due to health, number of disability days and number of restricted activity days. RESULTS: Average data from the 4- and 7-month assessments in both studies, intervention patients reported fewer somatic symptoms (OR 0.68, 95% CI 0.46, 0.99) and more favourable overall health (OR 0.50, 95% CI 0.28, 0.91). While intervention patients fared better on other measures of functional impairment and disability, none of these differences reached statistical significance. CONCLUSIONS: More effective acute-phase depression treatment reduced somatic distress and improved self-rated overall health. The absence of a significant intervention effect on other disability measures may reflect the brief treatment and follow-up period and the influence of other individual and environmental factors on disability.

Simon GE, Revicki D, Heiligenstein J, Grothaus L, VonKorff M, Katon WJ, Hylan TR, (2000). Recovery from depression, work productivity, and health care costs among primary care patients. General Hospital Psychiatry, 22, 153-62.
Abstract: We describe a secondary analysis of data from a randomized trial conducted at seven primary care clinics of a Seattle area HMO. Adults with major depression (n=290) beginning antidepressant treatment completed structured interviews at baseline, 1, 3, 6, 9, 12, 18, and 24 months. Interviews examined clinical outcomes (Hamilton Depression Rating Scale and depression module of the Structured Clinical Interview for DSM-IIIR), employment status, and work days missed due to illness. Medical comorbidity was assessed using computerized pharmacy data, and medical costs were assessed using the HMO's computerized accounting data. Using data from the 12-month assessment, patients were classified as remitted (41%), improved but not remitted (47%), and persistently depressed (12%). After adjustment for depression severity and medical comorbidity at baseline, patients with greater clinical improvement were more likely to maintain paid employment (P=.007) and reported fewer days missed from work due to illness (P<.001). Patients with better 12-month clinical outcomes had marginally lower health care costs during the second year of follow-up (P=.06). We conclude that recovery from depression is associated with significant reductions in work disability and possible reductions in health care costs. Although observational data cannot definitively prove any causal relationships, these longitudinal results strengthen previous findings regarding the economic burden of depression on employers and health insurers.

Simon GE. Cost-effectiveness of a collaborative care program for primary care patients with persistent depression. Am J Psychiatry. 2001; 158:1638-1644.
OBJECTIVE: The authors evaluated the incremental cost-effectiveness of stepped collaborative care for patients with persistent depressive symptoms after usual primary care management. METHOD: Primary care patients initiating antidepressant treatment completed a standardized telephone assessment 6-8 weeks after the initial prescription. Those with persistent major depression or significant subthreshold depressive symptoms were randomly assigned to continued usual care or collaborative care. The collaborative care included systematic patient education, an initial visit with a consulting psychiatrist, 2-4 months of shared care by the psychiatrist and primary care physician, and monitoring of follow-up visits and adherence to medication regimen. Clinical outcomes were assessed through blinded telephone assessments at 1, 3, and 6 months. Health services utilization and costs were assessed through health plan claims and accounting data. RESULTS: Patients receiving collaborative care experienced a mean of 16.7 additional depression-free days over 6 months. The mean incremental cost of depression treatment in this program was $357. The additional cost was attributable to greater expenditures for antidepressant prescriptions and outpatient visits. No offsetting decrease in use of other health services was observed. The incremental cost-effectiveness was $21.44 per depression-free day. CONCLUSIONS: A stepped collaborative care program for depressed primary care patients led to substantial increases in treatment effectiveness and moderate increases in costs. These findings are consistent with those of other randomized trials. Improving outcomes of depression treatment in primary care requires investment of additional resources, but the return on this investment is comparable to that of many other widely accepted medical interventions.

Stewart WF, Ricci JA, Chee E, Hahn SR, Morganstein D (2003). Cost of lost productive work time among US workers with depression. Journal of the American Medical Association, 289(23): 3135-3144.
Abstract: CONTEXT: Evidence consistently indicates that depression has adversely affected work productivity. Estimates of the cost impact in lost labor time in the US workforce, however, are scarce and dated. OBJECTIVE: To estimate the impact of depression on labor costs (ie, work absence and reduced performance while at work) in the US workforce. DESIGN, SETTING, AND PARTICIPANTS: All employed individuals who participated in the American Productivity Audit (conducted August 1, 2001-July 31, 2002) between May 20 and July 11, 2002, were eligible for the Depressive Disorders Study. Those who responded affirmatively to two depression-screening questions (n = 692), as well as a 1:4 stratified random sample of those responding in the negative (n = 435), were recruited for and completed a supplemental interview using the Primary Care Evaluation of Mental Disorders Mood Module for depression, the Somatic Symptom Inventory, and a medical and treatment history for depression. Excess lost productive time (LPT) costs from depression were derived as the difference in LPT among individuals with depression minus the expected LPT in the absence of depression projected to the US workforce. MAIN OUTCOME MEASURE: Estimated LPT and associated labor costs (work absence and reduced performance while at work) due to depression. RESULTS: Workers with depression reported significantly more total health-related LPT than those without depression (mean, 5.6 h/wk vs an expected 1.5 h/wk, respectively). Eighty-one percent of the LPT costs are explained by reduced performance while at work. Major depression accounts for 48% of the LPT among those with depression, again with a majority of the cost explained by reduced performance while at work. Self-reported use of antidepressants in the previous 12 months among those with depression was low (<33%) and the mean reported treatment effectiveness was only moderate. Extrapolation of these survey results and self-reported annual incomes to the population of US workers suggests that US workers with depression employed in the previous week cost employers an estimated 44 billion dollars per year in LPT, an excess of 31 billion dollars per year compared with peers without depression. This estimate does not include labor costs associated with short- and long-term disability. CONCLUSIONS: A majority of the LPT costs that employers face from employee depression is invisible and explained by reduced performance while at work. Use of treatments for depression appears to be relatively low. The combined LPT burden among those with depression and the low level of treatment suggests that there may be cost-effective opportunities for improving depression-related outcomes in the US workforce.

Von Korff M, Ormel J, Katon W, Lin EH (1992). Disability and depression among high utilizers of health care. A longitudinal analysis. Archives of General Psychiatry, 49, 91-100.
Abstract: We evaluated, among depressed medical patients who are high utilizers of health care, whether improved vs unimproved depression is associated with differences in the course of functional disability. At baseline, six months, and twelve months, depression and disability were assessed among a sample of enrollees in health maintenance organizations (N = 145) in the top decile of users of ambulatory health care who exceeded the 70th percentile of health maintenance organization population norms for depression. Improved depression was defined as a reduction of at least one third in depressive symptoms averaged across the two follow-up times. At the 12-month follow-up, persons with severe-improved depression experienced a 36% reduction in disability days (79 days per year to 51 days per year) and a 45% reduction in disability score. Persons with moderate-improved depression experienced a 72% reduction in disability days (62 days per year to 18 days per year) and a 40% reduction in disability score. In contrast, persons with severe-unimproved depression reported 134 disability days per year at baseline, while persons with moderate-unimproved depression reported 77 disability days per year at baseline. Neither group with unimproved depression showed improvement in either disability days or disability score during the 1-year follow-up period. High utilizers of health care with severe-unimproved depression were more likely to have current major depression and to be unemployed. Improved (relative to unimproved) depression was associated with borderline differences in the severity of physical disease and in the percent married. We conclude that depression and disability showed synchrony in change over time. However, depression and disability may show synchrony in change with disability because both depression and disability are controlled by some other factor that influences the chronicity of depression (eg, chronic disease or personality disorder). The finding of synchronous change of depression and disability provides a rationale for randomized controlled trials of depression treatments among depressed and disabled medical patients to determine whether psychiatric intervention might improve functional status in such patients. Such research is needed to determine whether there is a causal relationship between depression offset and reductions in functional disability.

Wang PS, Beck AL, Berglund P, McKenas DK, Pronk NP, Simon GE, Kessler RC. Effects of major depression on moment-in-time work performance. Am J Psychiatry. 2004 Oct;161(10):1885-91.
OBJECTIVE: Although major depression is thought to have substantial negative effects on work performance, the possibility of recall bias limits self-report studies of these effects. The authors used the experience sampling method to address this problem by collecting comparative data on moment-in-time work performance among service workers who were depressed and those who were not depressed. METHOD: The group studied included 105 airline reservation agents and 181 telephone customer service representatives selected from a larger baseline sample; depressed workers were deliberately oversampled. Respondents were given pagers and experience sampling method diaries for each day of the study. A computerized autodialer paged respondents at random time points. When paged, respondents reported on their work performance in the diary. Moment-in-time work performance was assessed at five random times each day over a 7-day data collection period (35 data points for each respondent). RESULTS: Seven conditions (allergies, arthritis, back pain, headaches, high blood pressure, asthma, and major depression) occurred often enough in this group of respondents to be studied. Major depression was the only condition significantly related to decrements in both of the dimensions of work performance assessed in the diaries: task focus and productivity. These effects were equivalent to approximately 2.3 days absent because of sickness per depressed worker per month of being depressed. CONCLUSIONS: Previous studies based on days missed from work significantly underestimate the adverse economic effects associated with depression. Productivity losses related to depression appear to exceed the costs of effective treatment.

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