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Epidemiology of Mood Disorders II: Analytic Epidemiology and the Search for Etiologic Clues William W. Eaton, PhD Johns Hopkins University
Epidemiology of Depression Risk Factors Sex/gender and natural history Diathesis/stress model Life event stressors Social supports Continued 3
Epidemiology of Depression Risk Factors Socioeconomic status (SES) and work life SES, social supports, and life stage Recency of birth 4
Gender Section A
Gender and Mood Disorders in Four Surveys Ages 26-64, Standardized to U.S. Age Distribution 20 MDD--Males BPD--Males 3.47/1 MDD--Females BPD--Females 1.98/1 Lifetime Prevalence (%) 15 1.76/1 10 2.3/1 5 1.25/1.86/1 NA.91/1 0 USA Edmonton Munich New Zealand Data from: Weissman, et al. (1993), J Affect Disord. 6
Risk Factors for Adult MDE Forest Plot Breslau, 1996 Catalano, 2000 Ginexi, 2000 Hwang, 2000 Kawakami, 1995 Messias, 2001 Patten, 2001 Pine, 1998 Female vs. Male.6.8 1 2 4 6 8 10 20 Relative Risk/Odds Ratio Adapted from: Mielke et al, 2002 7
Incidence, Recurrence, and Duration by Age and Sex Baltimore ECA Follow-Up Incidence RR Recurrence RR Duration in Weeks Male 1 1 0 Female 1.98 0.95 4.23 18-29 1 1 0 30-44 0.64 0.75 7.98 45+ 0.18 0.11-0.23 Recurrence *** *** -11.25 Source: Eaton, et al. (1997), Arch Gen Psychiatry 8
Summary Prevalence of depression is higher in females than males Caused by relationship of incidence of depression to gender Gender operates only in the first episode 9
Stress, Heredity, and Social Support Section B
Diathesis Stress Model 11
... in London Percent with Severe Events Prior to Onset Cases (Patients) Cases (Survey) Controls (Survey) One or More Severe Events No Severe Events 61% 68% 20% 39% 32% 80% Total Percent 100% 100% 100% Number of Persons 114 76 382 Source: Brown and Harris (1978), Social Origins of Depression, pp. 57-58, 103 12
Interaction of Life Events and Heredity Onset of Major Depression in 2,164 Female Twins Percent with Onset 16 14 12 10 8 6 4 2 DZ Co-Twin Normal MZ Co-Twin Normal DZ Co-Twin Case MZ Co-Twin Case 0 Absent Present Adapted from Kendler et al. (1995), Am J Psychiatry Severe Life Event in Month of Onset 13
Support Percent with Onset of Disorder Confidant No Confidant No Recent Life Stress 1% 3% Recent Life Stress 4% 38% Source: Brown, et al. (1975), Sociology 14
SES, Work, and Life Stage Section C
Odds Ratios for Prevalence of Major Depression in the Lower Socio-Economic Group Adapted from: Lorant, et al. (2003), Am J Epidemiol. 16
Odds Ratios of Major Depression Five Incidence and Four Persistence Studies Adapted from: Lorant, et al. (2003), Am J Epidemiol. 17
Predictors of Episodes of Depression Baseline (1981) Family Background Background Prevalence Father s job percentile 1.00 1.01 Father s grade level.99*.99* Follow-Up (1993-96) Prevalence Incidence Parental Depression 1.91+ 1.77*** 1.59** 1.76** Highest grade, baseline.90*.91.92.89 Job percentile of first job 1.00 1.00 Occupational Career Job percentile at baseline 1.00 1.00 1.00 Household income percentile, baseline.99 1.00 1.00 Financial dependency at baseline 1.75 2.42*** 2.46** Job percentile at Follow-up 1.00 1.00 Household income percentile, follow-up 1.00 1.00 Other income, follow-up.61.89 Prior year life events 1.55* 1.59*** 1.88+ * p <.1 ** p <.05 *** p <.01 + p <.005 Data from: Eaton, et al. (2001), J Health Soc Behav Continued 18
Predictors of Episodes of Depression Baseline (1981) Family Background Background Prevalence Father s job percentile 1.00 1.01 Father s grade level.99*.99* Follow-Up (1993-96) Prevalence Incidence Parental Depression 1.91+ 1.77*** 1.59** 1.76** Highest grade, baseline.90*.91.92.89 Job percentile of first job 1.00 1.00 Occupational Career Job percentile at baseline 1.00 1.00 1.00 Household income percentile, baseline.99 1.00 1.00 Financial dependency at baseline 1.75 2.42*** 2.46** Job percentile at Follow-up 1.00 1.00 Household income percentile, follow-up 1.00 1.00 Other income, follow-up.61.89 Prior year life events 1.55* 1.59*** 1.88+ * p <.1 ** p <.05 *** p <.01 + p <.005 Data from: Eaton, et al. (2001), J Health Soc Behav 19
Depression among Women in London 100 80 60 40 20 0 Social Class, Life Stage, and Intimacy 100 Percent with Confidant (Top) Lower Class Middle Class Lower Class 80 60 40 20 Middle Class 0 Young, No Children Child Less than Six Children 6 to 14 Children 15 and Over Older, No Children Percent with Depression (Bottom) Redrawn from Brown, Bhrolchain, and Harris (1975) Life Stage Continued 20
Depression among Women in London 100 80 60 40 20 0 Social Class, Life Stage, and Intimacy 100 Percent with Confidant (Top) Lower Class Middle Class Lower Class 80 60 40 20 Middle Class 0 Young, No Children Child Less than Six Children 6 to 14 Children 15 and Over Older, No Children Percent with Depression (Bottom) Redrawn from Brown, Bhrolchain, and Harris (1975) Life Stage 21
Risk Factors for Adult MDE Work Environment Job Overload Job Unsuitability Absenteeism from Work Absenteeism from Work High Psychological Demand High Psychological Demand Low Decision Latitude Low Decision Latitude High Job Strain High Job Strain High Job Insecurity High Job Insecurity Low Supervisor Support Low Supervisor Support a a b b b b b b c c c c c c Color Category Forest Plot Redrawn from Mielke, et al. (2002).1.2.3.4.5 1 2 3 4 5 10 Relative Risk/Odds Ratio 20 30 22
Recency of Birth Section D
Birth Cohort Cumulative Percent Ever Depressed Females in Five ECA Sites 0.2 0.15 0.1 Births after 1935 Births before 1935 1955-1964 1945-1954 1935-1944 1925-1934 1915-1924 1905-1914 0.05 0 0-04 0-14 15-24 25-34 35-44 44-54 55-64 65-74 Redrawn from Wickramaratne, et al. (1989), J Clin Epidemiol. Age in Years 24
Community Settings the Cohort Effect Has Appeared Five urban areas in the United States Edmonton, Alberta Puerto Rico Munich Germany Paris, France Beirut, Lebanon Christchurch, New Zealand Taiwan Florence, Italy Source: Cross-National Collaborative Group, JAMA (1992) 25
Possible Explanations for Cohort Effects Older cohorts are less introspective More treatment available leads to better recall People with depression die sooner Older subjects forget more distant episodes 26
Recall Simulation and Major Depression 1% of Episodes Forgotten Each Year Redrawn from Giuffra and Risch (1994), Psycho Med. Continued 27
Recall Simulation and Major Depression 3% of Episodes Forgotten Each Year Redrawn from Giuffra and Risch (1994), Psycho Med. Continued 28
Recall Simulation and Major Depression Forgetting Increases with Age Cohort: 1900, 10%; 1930, 5%; 1960, 1% Redrawn from Giuffra and Risch (1994), Psycho Med. 29
Trends in Incidence of Depressive Disorder 30
Trend in Suicide among Youth Rates per 100,000 Population 16 14 12 Holland 20-29 US 15-24 10 Rate 8 6 4 2 Born after 1945 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 Adapted from: Diekstra (1993), Acta Psychiatr Scand Supl Year of Suicide 31