Prevalence and effects of mood disorders on work performance in a nationally representative sample of U.S. workers.

OBJECTIVE: Research on the workplace costs of mood disorders has focused largely on major depressive episodes. Bipolar disorder has been overlooked both because of the failure to distinguish between major depressive disorder and bipolar disorder and by the failure to evaluate the workplace costs of mania/hypomania. METHOD: The National Comorbidity Survey Replication assessed major depressive disorder and bipolar disorder with the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI) and work impairment with the WHO Health and Work Performance Questionnaire. A regression analysis of major depressive disorder and bipolar disorder predicting Health and Work Performance Questionnaire scores among 3,378 workers was used to estimate the workplace costs of mood disorders. RESULTS: A total of 1.1% of the workers met CIDI criteria for 12-month bipolar disorder (I or II), and 6.4% meet criteria for 12-month major depressive disorder. Bipolar disorder was associated with 65.5 and major depressive disorder with 27.2 lost workdays per ill worker per year. Subgroup analysis showed that the higher work loss associated with bipolar disorder than with major depressive disorder was due to more severe and persistent depressive episodes in those with bipolar disorder than in those with major depressive disorder rather than to stronger effects of mania/hypomania than depression. CONCLUSIONS: Employer interest in workplace costs of mood disorders should be broadened beyond major depressive disorder to include bipolar disorder. Effectiveness trials are needed to study the return on employer investment of coordinated programs for workplace screening and treatment of bipolar disorder and major depressive disorder.

Validity of the assessment of bipolar spectrum disorders in the WHO CIDI 3.0.

OBJECTIVE: Although growing interest exists in the bipolar spectrum, fully structured diagnostic interviews might not accurately assess bipolar spectrum disorders. A validity study was carried out for diagnoses of threshold and sub-threshold bipolar disorders (BPD) based on the WHO Composite International Diagnostic Interview (CIDI) in the National Comorbidity Survey Replication (NCS-R). CIDI BPD screening scales were also evaluated. METHOD: The NCS-R is a nationally representative US household population survey (n=9282 using CIDI to assess DSM-IV disorders. CIDI diagnoses were evaluated in blinded clinical reappraisal interviews using the non-patient version of the Structured Clinical Interview for DSM-IV (SCID). RESULTS: Excellent CIDI-SCID concordance was found for lifetime BP-I (AUC=.99 kappa=.88, PPV=.79, NPV=1.0), either BP-II or sub-threshold BPD (AUC=.96, kappa=.88, PPV=.85, NPV=.99), and overall bipolar spectrum disorders (i.e., BP-I/II or sub-threshold BPD; AUC=.99, kappa=.94, PPV=.88, NPV=1.0). Concordance was lower for BP-II (AUC=.83, kappa=.50, PPV=.41, NPV=.99) and sub-threshold BPD (AUC=.73, kappa=.51, PPV=.58, NPV=.99). The CIDI was unbiased compared to the SCID, yielding a lifetime bipolar spectrum disorders prevalence estimate of 4.4%. Brief CIDI-based screening scales detected 67-96% of true cases with positive predictive value of 31-52%. LIMITATION: CIDI prevalence estimates are still probably conservative, though, but might be improved with future CIDI revisions based on new methodological studies with a clinical assessment more sensitive than the SCID to sub-threshold BPD. CONCLUSIONS: Bipolar spectrum disorders are much more prevalent than previously realized. The CIDI is capable of generating conservative diagnoses of both threshold and sub-threshold BPD. Short CIDI-based scales are useful screens for BPD.

Psychosocial disability in the course of bipolar I and II disorders: a prospective, comparative, longitudinal study.

CONTEXT: Evidence of psychosocial disability in bipolar disorder is based primarily on bipolar I disorder (BP-I) and does not relate disability to affective symptom severity and polarity or to bipolar II disorder (BP-II). OBJECTIVE: To provide detailed data on psychosocial disability in relation to symptom status during the long-term course of BP-I and BP-II. DESIGN: A naturalistic study with 20 years of prospective, systematic follow-up. SETTING: Inpatient and outpatient treatment facilities at 5 US academic centers. Patients One hundred fifty-eight patients with BP-I and 133 patients with BP-II who were followed up for a mean (SD) of 15 (4.8) years in the National Institute of Mental Health Collaborative Depression Study. MAIN OUTCOME MEASURES: The relationship, by random regression, between Range of Impaired Functioning Tool psychosocial impairment scores and affective symptom status in 1-month periods during the long-term course of illness from 6-month and yearly Longitudinal Interval Follow-up Evaluation interviews. RESULTS: Psychosocial impairment increases significantly with each increment in depressive symptom severity for BP-I and BP-II and with most increments in manic symptom severity for BP-I. Subsyndromal hypomanic symptoms are not disabling in BP-II, and they may even enhance functioning. Depressive symptoms are at least as disabling as manic or hypomanic symptoms at corresponding severity levels and, in some cases, significantly more so. At each level of depressive symptom severity, BP-I and BP-II are equally impairing. When asymptomatic, patients with bipolar disorder have good psychosocial functioning, although it is not as good as that of well controls. CONCLUSIONS: Psychosocial disability fluctuates in parallel with changes in affective symptom severity in BP-I and BP-II. Important findings for clinical management are the following: (1) depressive episodes and symptoms, which dominate the course of BP-I and BP-II, are equal to or more disabling than corresponding levels of manic or hypomanic symptoms; (2) subsyndromal depressive symptoms, but not subsyndromal manic or hypomanic symptoms, are associated with significant impairment; and (3) subsyndromal hypomanic symptoms appear to enhance functioning in BP-II.

The prevalence and disability of bipolar spectrum disorders in the US population: re-analysis of the ECA database taking into account subthreshold cases.

BACKGROUND: Despite emerging international consensus on the high prevalence of the bipolar spectrum in both clinical and community samples, many skeptics contend that narrowly defined bipolar disorder with a lifetime rate of about 1% represents a more accurate estimate of prevalence. This may in part be due to the fact that higher figures proposed for the bipolar spectrum (5-8%) have not been based on national data and have not included all levels of manic symptom severity. In the present secondary analyses of the US National Epidemiological Catchment Area (ECA) database, we provide further clarification on this fundamental public health issue. METHODS: All respondents in the first wave (first interview) of the ECA household five site sample (n=18252) were classified on the basis of DSM-III criteria into lifetime manic and hypomanic episodes, as well as those with at least two lifetime manic/hypomanic symptoms below the threshold for at least 1 week duration (subsyndromal manic symptoms [SSM] group). Odds ratios were calculated on lifetime service utilization for mental health problems, measures of adverse psychosocial outcome, and suicidal behavior compared to subjects with no mental disorders or manic symptoms. RESULTS: As originally reported nearly two decades ago by the primary investigators of the ECA, the lifetime prevalence for manic episode was 0.8%, and for hypomania, 0.5%. What is new here is the inclusion of subthreshold SSM subjects, which accounted for 5.1%, yielding a total of 6.4% lifetime prevalence for the bipolar spectrum. All three (manic, hypomanic and SSM) groups had greater marital disruption. There were significant increases in lifetime health service utilization, need for welfare and disability benefits and suicidal behavior when the SSM, hypomanic and manic subjects were compared to the no mental disorder group. Suicidal behavior was non-significantly highest in the hypomanic (bipolar II) group. Otherwise, hypomanic and manic groups had comparable level of service utilization and social disruption. LIMITATIONS: Comorbid disorders, which might influence functioning, were not included in the present analyses. CONCLUSION: These secondary analyses of the US National ECA database provide convincing evidence for the high prevalence of a spectrum of bipolarity in the community at 6.4%, and indicate that subthreshold cases are at least five times more prevalent than DSM-based core syndromal diagnoses at about 1%. These SSM subjects, who met the criteria of "caseness" from the point of view of harmful dysfunction, are of great theoretical and public health significance.