Table 1.
Summary of Key Studies Assessing the Disability Associated With Major Depressive Disorder (MDD)
| Reference | Study Description | Primary Results |
| Arnow et al, 200695 | Patients with and without MDD and chronic pain were evaluated with the SF-8 to assess the impact of MDD on health-related quality of life | MDD/disabling pain: 31.3; P < .0001 vs all groups |
| MDD/nondisabling pain: 27.9; P < .0001 vs controls | ||
| MDD alone: 26.7; P < .0001 vs controls | ||
| Neither MDD nor pain: 16.8 | ||
| Barefoot et al, 199616 | Patients with coronary artery disease with and without depression (n = 1,250) were followed for a median of 15 y | Risk of cardiac death |
| χ21 = 9.25; P = .002 vs nondepressed patients | ||
| Total mortality | ||
| χ21 = 14.67; P < .001 vs nondepressed patients | ||
| 51% of moderate-to-severe depression group died of cardiac causes | ||
| Baune et al, 200744 | Patients with common medical disorders with and without comorbid MDD were assessed to determine the impact of MDD on functioning and health outcomes | Risk of experiencing disability days (mean risk vs those without comorbid MDD) |
| Overall: 1.34; P = .012 | ||
| Neurologic: 2.62; P = .0005 | ||
| Gastrointestinal: 1.38; P = .079 | ||
| Cardiovascular: 1.16; P = .359 | ||
| Endocrine: 1.70; P = .047 | ||
| Allergic: 1.06; P = .399 | ||
| Respiratory: 2.02; P = .069 | ||
| Beekman et al, 200245 | Adults aged 55–85 y (n = 2,200) were followed for 3 y to determine the impact of MDD on use of health services | Risk associated with the onset of MDD, OR (95% CI) |
| Disability days: 2.10 (1.38–3.20) | ||
| Hospital admission: 1.80 (1.15–2.81) | ||
| Use of paramedical services: 1.88 (1.15–3.08) | ||
| Impaired general satisfaction: 4.11 (2.65–6.38) | ||
| Risk associated with persistent MDD, OR (95% CI) | ||
| Fewer physician visits: 0.38 (0.19–0.75) | ||
| Impaired general satisfaction: 3.73 (2.04–6.83) | ||
| Dissatisfaction with services: 3.08 (1.39–6.83) | ||
| Birnbaum et al, 20038 | The disability costs associated with depression were analyzed by gender | Total costs |
| Males with MDD: $8,502 (work absence: 42%; prescription drugs: 11%; medical: 48%) | ||
| Males without MDD: $3,458 (work absence: 39%; prescription drugs: 13%; medical: 47%) | ||
| Females with MDD: $9,265 (work absence: 50%; prescription drugs: 11%; medical: 40%) | ||
| Females without MDD: $5,091 (work absence: 53%; prescription drugs: 11%; medical: 36%) | ||
| Breslau et al, 200396 | Patients with migraines, patients with severe headaches, and nonheadache controls were followed for 2 y to assess the relationship between MDD and headaches | Risk for migraine, OR (95% CI) |
| Controls with MDD: 3.4 (1.4–8.7); P < .01 vs controls without MDD | ||
| Risk for MDD, OR (95% CI) | ||
| Migraine without MDD: 5.8 (2.7–12.3); P < .0001 vs controls without headache or MDD | ||
| Breslin et al, 200697 | Adults aged 18–60 y were followed for 4 y and assessed to determine the effect of MDD on activity limitation | Risk for activity limitation associated with MDD, OR |
| Home | ||
| Female: 3.8 | ||
| Male: 4.2 | ||
| Work | ||
| Female: 3.4 | ||
| Male: 3.4 | ||
| Other | ||
| Female: 3.5 | ||
| Male: 5.7 | ||
| Burton et al, 200498 | Depressed employees (n = 1,491) from a large financial services company were assessed with the WLQ | Risk for low score on WLQ scales, OR (95% CI) |
| Time: 2.05 (1.83–2.30); P < .05 | ||
| Physical: 1.49 (1.32–1.68); P < .05 | ||
| Mental: 2.46 (2.20–2.76); P < .05 | ||
| Output: 2.24 (2.00–2.50); P < .05 | ||
| Carta et al, 200399 | Direct health care costs of patients with depression, patients with a chronic somatic illness, and healthy controls were compared | Hospital days, mean |
| Depressed: 5.8 d (P < .0001 vs somatic and healthy) | ||
| Antidepressant treatment: 2.0 d (P < .04 vs no antidepressant treatment) | ||
| No antidepressant treatment: 7.4 d | ||
| Somatic: 4.3 d | ||
| Healthy: 1.1 d | ||
| Daily drug expenditures, mean | ||
| Depressed: €0.53 (P < .0001 vs somatic and healthy) | ||
| Antidepressant treatment: €0.65 (P = .28 vs no antidepressant treatment) | ||
| No antidepressant treatment: €0.51 | ||
| Somatic: €0.52 | ||
| Healthy: €0.21 | ||
| Drug and hospitalization expenditures during previous year | ||
| Depressed: €2,289.41 (P < .0001 vs somatic and healthy) | ||
| Antidepressant treatment: €1,715.81 (P < .04 vs no antidepressant treatment) | ||
| No antidepressant treatment: €2,528.40 | ||
| Somatic: €1,750.37 | ||
| Healthy: €474.11 | ||
| Cramer et al, 2003100 | Epilepsy patients with mild-moderate (n = 74) or severe (n = 166) depression and those without depression (n = 443) were assessed with a seizure severity scale | Patients with mild-moderate and severe depression experienced more severe, bothersome, and frequent seizures that were more difficult to recover from than nondepressed patients |
| Dorenlot et al, 200546 | Dementia outpatients were followed for 3 y to assess the impact of MDD on rates of institutionalization | Risk for institutionalization, OR (95% CI) |
| MDD: 1.6 (1.1–2.5); P = .043 vs non-MDD controls | ||
| Druss et al, 200010 | Employees (n = 15,153) of a large US corporation who filed health claims were assessed on health care and disability costs | Depressive disorder (MDD, dysthymia, depressive disorder not otherwise specified) |
| Sick days: 9.9; P < .05 vs diabetes, heart disease, hypertension, back problems, all other | ||
| Per capita health/disability costs: $5,415; P < .01 vs hypertension, all other | ||
| Diabetes, heart disease, hypertension, or back problem with comorbid depressive disorder | ||
| Health care costs: $7,407; P < .001 vs any disorder without comorbid depressive disorder | ||
| Sick days: 13.5; P < .01 vs any disorder without comorbid depressive disorder | ||
| Per capita health care costs: $7,906; P < .001 vs any disorder without comorbid depressive disorder | ||
| Druss et al, 1999101 | Health care costs of patients with MDD (n = 1,081) were compared with nondepressed controls | Increase in outpatient care costs: $1,326; P < .001 vs nondepressed controls |
| Increase in inpatient care costs: $1,581; P < .001 vs nondepressed controls | ||
| Egede et al, 2004102 | Patients with MDD and diabetes, MDD without diabetes, and diabetes only and nondepressed, nondiabetic controls were assessed on their physical functioning | Prevalence of overall functional disability |
| MDD/diabetes: 77.8%; P < .0001 vs controls | ||
| Diabetes only: 58.1%; P < .0001 vs controls | ||
| MDD only: 51.3%; P < .0001 vs controls | ||
| No MDD/no diabetes: 24.5%; P < .0001 vs controls | ||
| Risk of functional disability, OR (95% CI) | ||
| MDD: 3.02 (2.66–3.44) | ||
| Diabetes: 2.46 (2.15–2.82) | ||
| MDD and diabetes: 6.15 (3.86–9.80) | ||
| Egede, 200747 | The 12-mo prevalence of MDD in patients with a number of CMDs was assessed to determine the effect of MDD on health care utilization | Risk, OR (95% CI) |
| ≥ 1 day absent from work | ||
| CMD: 0.98 (0.80–1.21) | ||
| CMD/MDD: 1.22 (0.88–1.68) | ||
| ≥ 1 day spent in bed | ||
| CMD: 0.97 (0.85–1.10) | ||
| CMD/MDD: 1.60 (1.28–2.00) | ||
| Functional disability: yes | ||
| CMD: 1.06 (0.91–1.24) | ||
| CMD/MDD: 2.48 (1.96–3.15) | ||
| Ford et al, 2004103 | The effect of depression on health care utilization was assessed | Patients with depression are significantly more likely to be high (14%; OR [95% CI]: 2.2 [1.2–3.9]) vs midrange (7%) health care utilizers |
| Frasure-Smith et al, 1993104 | Patients who met criteria for a myocardial infarction and screened positively for MDD (n = 35) were followed for 6 mo to compare mortality rates with nondepressed controls (n = 187) | Risk for mortality, OR (95% CI) |
| 5.74 (4.61–6.87); P < .0006 vs nondepressed controls | ||
| Greenberg et al, 20037 | The economic burden of depression for the year 2000 was calculated from a variety of sources presenting US data | Inpatient: $8,883 (million) |
| Outpatient: $6,083 (million) | ||
| Pharmaceutical: $10,400 (million) | ||
| Absenteeism: $36,248 (million) | ||
| Presenteeism: $15,195 (million) | ||
| Haarasilta et al, 2005105 | Adolescents and young adults (n = 942) were followed for 1 y to assess the relationship between MDD and health | Risk of poor health, OR (95% CI) |
| Chronic illness: 1.59 (0.93–2.70) | ||
| Diagnosed chronic illness: 1.76 (1.03–3.01) | ||
| Respiratory allergies: 2.71 (1.14–6.45) | ||
| Other allergies: 1.31 (0.65–2.66) | ||
| Musculoskeletal: 1.51 (0.60–3.79) | ||
| Neurologic: 1.85 (0.53–6.45) | ||
| Migraine: 3.67 (0.96–14.0) | ||
| Disabling chronic illness: 1.35 (0.55–3.31) | ||
| Poor self-perceived health: 2.56 (1.23–5.34) | ||
| ≥ 3 sick days: 2.01 (1.23–3.29) | ||
| Hoge et al, 2002106 | Health care utilization of active military personnel between 1990 and 1999 was calculated to identify the effect that a psychiatric diagnosis has on this metric | MDD (1990–1999) |
| Hospitalizations: 11,264 | ||
| Ambulatory visits: 100,866 | ||
| Janssens et al, 2003107 | Patients with multiple sclerosis (n = 101) were screened for depression to assess its relationship to SF-36 scores | SF-36 physical health |
| Physical functioning: β = −.45; P < .001 | ||
| Role-physical functioning: β = −.53; P < .001 | ||
| Bodily pain: β = −.43; P < .001 | ||
| General health: β = −.41; P < .001 | ||
| SF-36 mental health | ||
| Vitality: β = −.51; P < .001 | ||
| Social functioning: β = −.57; P < .001 | ||
| Role-emotional functioning: β = −.45; P < .001 | ||
| Mental health: β = −.64; P < .001 | ||
| Katon et al, 200313 | The medical costs of older adults diagnosed with MDD were compared with nondepressed controls | Cost ratios associated with MDD, OR (95% CI) |
| Total: 1.49 (1.28–1.72) | ||
| Total outpatient: 1.47 (1.36–1.56) | ||
| Outpatient depression: 1.78 (1.42–2.24) | ||
| Outpatient nondepression: 1.36 (1.18–1.56) | ||
| Kaufmann et al, 199917 | Patients with myocardial infarction (n = 331) were followed for 12 mo to assess the effect of MDD (27%) on mortality in these patients | Mortality |
| MDD: 18.7%; OR = 2.33 (95% CI = 1.16–4.65); P = .015 | ||
| Non-MDD: 9.0% | ||
| Keenan-Miller et al, 2007108 | Adolescents were followed for 5 y to assess the effect of MDD on health outcomes in young adulthood | MDD at age 15 y, β (95% CI) |
| Interviewer-rated health: .16 (0.04–0.29); P = .01 | ||
| SF-36 self-rated health: 1.10 (0.17–2.02); P = .02 | ||
| SF-36 physical limitations: .62 (−0.22–1.45); P = .15 | ||
| Visit to medical professional: 1.26 (0.61–1.90); P = .001 | ||
| SF-36 work role impairment: .38 (0.15–0.60); P = .001 | ||
| Chronic illness at age 20 y, OR (95% CI): 1.62 (0.98–2.67); P = .06 | ||
| Kessler et al, 1999109 | Work disability data from 2 nationally representative populations were assessed to quantify the effect of 30 d of experiencing MDD | Short-term work disability: 45.9% (P < .05 vs non-MDD workers) |
| Work disability days: 7.6 (P < .05 vs non-MDD workers) | ||
| Salary-equivalent disability costs: $267 | ||
| Kessler et al, 2003110 | The disability data from a nationally representative sample diagnosed with hypertension, arthritis, asthma, and ulcer with MDD were compared | Difference in number of role impairment days |
| Hypertension: 1.6 (P = NS vs no comorbid MDD) | ||
| Arthritis: 2.2 (P = NS vs no comorbid MDD) | ||
| Asthma: 2.4 (P < .05 vs no comorbid MDD) | ||
| Ulcer: 3.1 (P < .05 vs no comorbid MDD) | ||
| Kessler et al, 20069 | Using NCS data, an analysis of performance was conducted in workers with MDD | Aggregated (total US population) impact of MDD |
| Absenteeism | ||
| Days per year (million): 72.2; P < .05 | ||
| Dollars per year (million): 11,742; P < .05 | ||
| Presenteeism | ||
| Days per year (million): 150.5; P < .05 | ||
| Dollars per year (million): 24,482; P < .05 | ||
| Total | ||
| Days per year (million): 225.0; P < .05 | ||
| Dollars per year (million): 36,602; P < .05 | ||
| Kouzis and Eaton, 1994111 | The predictors of emotional disability days were assessed | Disability associated with MDD |
| ≥ 1 disability day: 44% | ||
| Risk for disability day: OR = 27.8 (95% CI = 6.93–108.96) | ||
| Lerner et al, 200423 | Work outcomes in employees with MDD (n = 75) were compared with healthy controls (n = 169) over 6 mo | WLQ scales (change from baseline to 6 mo) |
| Physical | ||
| MDD: –3.3; P = NS | ||
| Controls: –0.8 | ||
| Time | ||
| MDD: –3.9; P = .014 | ||
| Controls: –0.2 | ||
| Mental | ||
| MDD: –9.4; P < .001 | ||
| Controls: –1.4 | ||
| Output | ||
| MDD: –12.0; P < .001 | ||
| Controls: –1.4 | ||
| Lerner et al, 2004112 | The effect of MDD on work productivity outcomes was assessed with the WLQ | WLQ scales |
| Mental-interpersonal: β = 50.8; P < .001 | ||
| Physical: β = 12.9; P = .004 | ||
| Time: β = 46.4; P < .001 | ||
| Output: β = 59.7; P < .001 | ||
| Days missed: 2.2; P < .001 | ||
| Lespérance et al, 2002113 | The association between 5-y risk of cardiac mortality and BDI severity score was assessed in patients with myocardial infarction (n = 879) | Cardiac mortality, OR (95% CI) |
| BDI score 5–9 vs < 5: 1.76 (0.98–3.17); P = .059 | ||
| BDI score 10–18 vs < 5: 3.17 (1.79–5.60); P < .001 | ||
| BDI score ≥ 19 vs < 5: 3.13 (1.56–6.27); P = .001 | ||
| Luber et al, 2000114 | The health care utilization of internal medicine outpatients with a diagnosis of MDD was compared to nondepressed controls over 1 y | Health care visits |
| MDD: 5.3; P < .001 vs controls | ||
| Controls: 2.9 | ||
| Total health care costs | ||
| MDD: $2,808; P = .001 vs controls | ||
| Controls: $1,891 | ||
| McIntyre et al, 2008115 | The impact of MDD on work functioning was assessed in a large, nationally representative sample | Risk associated with MDD, OR (95% CI) |
| ≥ 1 disability day in past 2 wk: 5.6 (4.1–7.7); P < .05 vs reference group | ||
| Good job security: 0.7 (0.6–0.8); P < .05 vs reference group | ||
| McQuaid et al, 1999116 | A population of primary care patients was used to assess the impact of MDD on work functioning | Missed work days |
| MDD: 58.1% (χ21 = 15.10; P < .001) | ||
| No MDD: 28.7% | ||
| Cut down on activities | ||
| MDD: 77.0% (χ21 = 9.03; P < .01) | ||
| No MDD: 54.3% | ||
| Muchmore et al, 2003117 | A predictor analysis was conducted in arthritis patients to assess the impact of arthritis and associated conditions, including MDD, on disability | Risk associated with comorbid depression, OR (95% CI) |
| Short-term disability: 1.01 (1.00–1.02); P < .0001 | ||
| Long-term disability: 2.23 (1.49–3.32); P < .0001 | ||
| Worker's compensation: 1.45 (1.25–1.70); P < .0001 | ||
| Papapetropoulos et al, 200648 | PD patients with and without MDD were assessed with PD rating scales | PD severity ratings |
| Unified Parkinson's Disease Rating Scale, mean (SD)118 | ||
| PD/MDD: 58.1 (32.3); P = .004 | ||
| PD: 37.3 (31.1) | ||
| Hoehn and Yahr, mean (SD)119 | ||
| PD/MDD: 2.7 (1.0); P = .07 | ||
| PD: 2.2 (0.9) | ||
| Schwab and England, activities of daily living performed, % (SD)120 | ||
| PD/MDD: 69.4% (22.1); P = .03 | ||
| PD: 78.4% (22.3) | ||
| Penninx et al, 2001121 | Mortality rates of patients diagnosed with and without CD and with and without MDD (n = 2,847) were compared | CD mortality, OR (95% CI) |
| No CD/MDD: 3.8 (1.4–10.6) | ||
| CD/No MDD: 3.4 (2.4–4.9) | ||
| CD/MDD: 10.5 (4.1–26.7) | ||
| IHD mortality, OR (95% CI) | ||
| No CD/MDD: 5.1 (1.6–16.9) | ||
| CD/No MDD: 4.5 (2.8–7.1) | ||
| CD/MDD: 17.7 (6.0–51.9) | ||
| Rovner, 1993122 | Nursing home patients were followed for 1 y to determine the effects of MDD on mortality rates | Risk for mortality in MDD, OR (95% CI): 1.59 (1.02–2.51) |
| Rumsfeld et al, 2003123 | Veterans’ affairs patients with a history of acute coronary syndrome with MDD (n = 1,431) were compared with nondepressed controls (n = 526) on a variety of health and quality of life outcomes | MDD vs controls, OR (95% CI) |
| Higher angina frequency: 2.40 (1.86–3.10); P < .001 | ||
| Greater physical limitations: 2.89 (2.17–3.86); P < .001 | ||
| Worse quality of life: 2.84 (2.16–3.72); P < .001 | ||
| Saarijärvi et al, 200236 | SF-36 data from patients with MDD and nondepressed controls were compared to determine the impact of MDD on quality of life | Relationship between SF-36 and BDI in MDD patients |
| Physical functioning (P ≤ .01) | ||
| Role functioning-physical (P < .001) | ||
| Role functioning-emotional (P < .01) | ||
| Energy (P = .0001) | ||
| Emotional well-being (P = .0001) | ||
| Social functioning (P = .0001) | ||
| Bodily pain (P = .0001) | ||
| General health perception (P = .0001) | ||
| Simon et al, 1995124 | Primary care patients with and without depression were compared on health care costs over 1 y following diagnosis | Annual total direct health care costs (eg, outpatient and inpatient mental health care, outpatient primary care, inpatient medical) |
| Depressed: $4,246 | ||
| Not depressed: $2,371 | ||
| Simon et al, 200049 | A 2-y follow-up of patients beginning antidepressant therapy assessed patients on a variety of work outcomes according to treatment response (ie, persistent [n = 35], improved [n = 137], or remitted [n = 118] depression) | Total health care costs |
| Persistent: $4,082 | ||
| Improved: $3,459 | ||
| Remitted: $2,816 | ||
| Employed, % (F2,262 = 5.88, P = .003) | ||
| Persistent: 70.1 | ||
| Improved: 83.8 | ||
| Remitted: 85.4 | ||
| Days of work missed (F2,226 = 10.62, P < .001) | ||
| Persistent: 16.80 | ||
| Improved: 10.37 | ||
| Remitted: 6.29 | ||
| Sobocki et al, 2006125 | Direct and indirect health costs (in year 2004 € million) collected from published studies conducted in 28 European countries were calculated | Total costs: €117,851 |
| Total direct costs: €41,688 | ||
| Hospitalization costs: €10,424 | ||
| Drug costs: €9,013 | ||
| Outpatient care: €22,252 | ||
| Total indirect costs: €76,163 | ||
| Morbidity: €72,189 | ||
| Mortality: €3,974 | ||
| Spitzer et al, 199535 | Primary care patients diagnosed with MDD (n = 115) were compared with controls on the subscales of the SF-20 to assess the impact of MDD on health-related quality of life | MDD vs nonpsychiatrically diagnosed patients |
| Physical functioning: –21.8; P < .001 | ||
| Bodily pain: –22.7; P < .001 | ||
| Role functioning: –45.5; P < .001 | ||
| General health: –30.4; P < .001 | ||
| Social functioning: –31.7; P < .001 | ||
| Mental health: –36.5; P < .001 | ||
| Stewart et al, 200328 | Depressed (n = 219) and nondepressed (n = 908) employees were compared on the cost of lost productive time | Lost productive time (hr/wk) |
| Absenteeism: 1.2 | ||
| Presenteeism: 7.2 | ||
| Total lost productive time: 8.4 | ||
| Cost of lost productive time ($ billion per year) | ||
| Absenteeism: 3.18 | ||
| Presenteeism: 18.18 | ||
| Total lost productive time: 21.36 | ||
| Sullivan et al, 1997126 | The physical functioning of patients with coronary artery disease was compared by baseline HDRS17 score and severity of depression over a 12-mo follow-up period | Relationship between functioning and baseline HDRS17 score |
| Physical function score at 12 mo: r = –0.27; P < .001 | ||
| Activity interference at 12 mo: r = 0.23; P < .01 | ||
| A significant association (ANOVA) between baseline depressive severity and physical functioning was observed at baseline (P < .001) and 12 mo (P = .01) | ||
| Sullivan et al, 2000127 | The physical functioning of patients with coronary artery disease was compared by baseline HDRS17 score and severity of depression over a 5-y follow-up period | Relationship between disability and HDRS17 score |
| SF-36 scales | ||
| Physical function: r = 0.26; P < .01 | ||
| Physical role: r = 0.36; P < .001 | ||
| Pain: r = 0.28; P < .01 | ||
| Social function: r = 0.31; P < .001 | ||
| Mental health: r = 0.21; P < .05 | ||
| Emotional role: r = 0.21; P < .05 | ||
| Vitality: r = 0.36; P < .0001 | ||
| General health: r = 0.33; P < .0001 | ||
| Unützer et al, 1997128 | A 4-y prospective study of Medicare enrollees ≥ 65 y who were screened for depression; health care costs were compared between those with depression (n = 353) and those without (n = 2,165) | Median costs 1 y after baseline |
| Depressed: $2,147 | ||
| Not depressed: $1,461 | ||
| Median costs 4 y after baseline | ||
| Depressed: $15,423 | ||
| Not depressed: $10,152 | ||
| Wells et al, 198930 | Data from 11,242 participants of the Medical Outcomes Study receiving treatment from general medical providers were subdivided into NCC and MDD groups | Physical functioning |
| NCC: 85.4; P < .05 | ||
| MDD: 81.3 | ||
| Social functioning | ||
| NCC: 91.7; P < .0001 | ||
| MDD: 83.3 | ||
| Role functioning | ||
| NCC: 87.0; P < .0001 | ||
| MDD: 74.6 |
Abbreviations: ANOVA = analysis of variance, BDI = Beck Depression Inventory, CD = cardiac disease, CMD = chronic medical disorder, HDRS17 = 17-item Hamilton Depression Rating Scale, IHD = ischemic heart disease, NCC = no chronic condition, NCS = National Comorbidity Survey, NS = not significant, OR = odds ratio, PD = Parkinson's disease, SF-8 = 8-item Short-Form Health Survey, SF-20 = 20-item Short-Form Health Survey, SF-36 = 36-item Short-Form Health Survey, WLQ = Work Limitations Questionnaire.