Enduring mental health: Prevalence and prediction

Abstract

We review epidemiological evidence indicating that most people will develop a diagnosable mental disorder, suggesting that only a minority experience enduring mental health. This minority has received little empirical study, leaving the prevalence and predictors of enduring mental health unknown. We turn to the population-representative Dunedin cohort, followed from birth to midlife, to compare people never-diagnosed with mental disorder (N = 171; 17% prevalence) to those diagnosed at 1-2 study waves, the cohort mode (N = 409). Surprisingly, compared to this modal group, never-diagnosed Study members were not born into unusually well-to-do families, nor did their enduring mental health follow markedly sound physical health, or unusually high intelligence. Instead, they tended to have an advantageous temperament/personality style, and negligible family history of mental disorder. As adults, they report superior educational and occupational attainment, greater life satisfaction, and higher-quality relationships. Our findings draw attention to "enduring mental health" as a revealing psychological phenotype and suggest it deserves further study. (PsycINFO Database Record

Figure 1

Proportion of cohort members in each study with a lifetime diagnosis of one or more mental disorders (see Table 1 for Study characteristics). Error bars represent 95% confidence intervals. Green bars represent estimates drawn from Danish registry data. Blue bars represent estimates from cross-sectional epidemiological surveys. Red bars represent estimates from prospective longitudinal studies with repeated mental health assessments. The estimates shown for the Christchurch Study and Dunedin Study are based on subsets (N = 1,041 and 988, respectively) of the full cohorts (N = 1,265 and 1,037, respectively) who contributed data to 3 + assessment waves. Age Range = age of cohort members at first mental health assessment, presented as a single number, range, or as “mean (SD)” where appropriate. No. of assessments = number of assessment waves in each longitudinal study; Length of follow-up = duration of longitudinal follow-up across assessments.

Figure 2

Mental disorder diagnoses in the Dunedin Cohort (N = 988). Panel A: Number of waves in which Dunedin Study members met criteria for a DSM diagnosis. The 6 waves represent ages 11–15, 18, 21, 26, 32, and 38. The red bar represents Study members with enduring mental health (those diagnosed at 0 waves). The light blue bars represent Study members with typical mental health histories (those diagnosed at 1–2 waves). The dark blue bars represent Study members diagnosed at 3 + waves. Panel B: Distribution of DSM diagnoses across assessment waves. Each thin horizontal line represents an individual Study member’s mental health history. Blue indicates that the Study member met criteria for a past-year DSM -defined psychiatric disorder during this assessment. Red indicates that the Study member did not meet criteria for a past-year DSM-defined psychiatric disorder during this assessment. Panel B shows that the largest proportion of Study members met diagnostic criteria at 1–2 waves, but that neither these individuals nor those diagnosed at 3 + waves were characterized by any particular developmental pattern (e.g., adolescent-limited course of disorder or late-onset forms of disorder).

Figure 3

Comparison of midlife outcomes for Dunedin cohort members in the 0 wave versus 1–2 wave mental health history groups. Error bars represent 95% confidence intervals. All outcome variables were standardized on the full cohort to a mean of 0 (representing the mean of the full cohort) and a standard deviation of 1. The means for the persistently diagnosed group are not shown here, but can be found in Table 3 in the online supplemental materials. Asterisks represent the statistical significance of the difference between groups, adjusted for sex. * p < .05.