Simulation studies of age-specific lifetime major depression prevalence

Abstract

BackgroundThe lifetime prevalence (LTP) of Major Depressive Disorder (MDD) is the proportion of a population having met criteria for MDD during their life up to the time of assessment. Expectation holds that LTP should increase with age, but this has not usually been observed. Instead, LTP typically increases in the teenage years and twenties, stabilizes in adulthood and then begins to decline in middle age. Proposed explanations for this pattern include: a cohort effect (increasing incidence in more recent birth cohorts), recall failure and/or differential mortality. Declining age-specific incidence may also play a role.MethodsWe used a simulation model to explore patterns of incidence, recall and mortality in relation to the observed pattern of LTP. Lifetime prevalence estimates from the 2002 Canadian Community Health Survey, Mental Health and Wellbeing (CCHS 1.2) were used for model validation and calibration.ResultsIncidence rates predicting realistic values for LTP in the 15-24 year age group (where mortality is unlikely to substantially influence prevalence) lead to excessive LTP later in life, given reasonable assumptions about mortality and recall failure. This suggests that (in the absence of cohort effects) incidence rates decline with age. Differential mortality may make a contribution to the prevalence pattern, but only in older age categories. Cohort effects can explain the observed pattern, but only if recent birth cohorts have a much higher (approximately 10-fold greater) risk and if incidence has increased with successive birth cohorts over the past 60-70 years.ConclusionsThe pattern of lifetime prevalence observed in cross-sectional epidemiologic studies seems most plausibly explained by incidence that declines with age and where some respondents fail to recall past episodes. A cohort effect is not a necessary interpretation of the observed pattern of age-specific lifetime prevalence.

Recall of recent and more remote depressive episodes in a prospective cohort study

“…In many studies, lifetime prevalence has been reported to decline with age, which has sometimes been interpreted as a birth cohort effect. Although multiple factors may contribute to the pattern, including differential mortality, these results corroborate previous studies indicating that recall bias is likely to be an important part of the explanation [19,20]. Lifetime prevalence may appear to diminish with age because episodes occurring earlier in life are not recalled by older survey respondents.…”

Lifetime risk and age of onset distributions of psychiatric disorders: analysis of national sample survey in South Korea

“…One recent report has suggested that the pattern of lifetime prevalence observed in crosssectional epidemiologic studies seems most plausibly explained by incidence that declines with age. They concluded that a cohort effect was not a necessary interpretation of the observed pattern of age-specific lifetime prevalence [38]. Prospective longitudinal studies are therefore needed to confirm if such an increase in prevalence among younger cohorts is real.…”

Depression—Factors, Symptoms, Prevention and the Role of Open Journal of Depression

“…More and more different groups in the societies suffer from depression. The age boundaries of this illness widen among the elderly people (Büchtemann et al, 2012;Bose & Neelakandan, 2013;Wood et al, 2010) and youth (Tezvaran, Akan, & Zahmaciog, 2012;Cole et al, 2012), but depression is more typical for the people advanced in age (about 50 years old) than for the young people (Wood et al, 2010;Patten, Gordon-Brown, & Meadows, 2010). The representatives of different kinds of occupations also experience this disorder in some moment of their life-even the doctors (Galán-Rodas et al, 2011).…”