Weight Change and Depression Among US Young Women During the Transition to Adulthood

Most adult mental health disorders first manifest during adolescence and early adulthood, and nearly 75% of lifetime diagnosable problems are evident by 24 years of age (1). Depression, the most commonly reported adolescent mental health disorder (2), is more prevalent in female than male adolescents, and this gender difference persists into adulthood (3). Estimates of depression prevalence based on broad assessment criteria indicating debilitating sadness suggest that roughly one-third of all female US high school students are depressed compared with one-fifth of male students (4). Estimates based on the Diagnostic and Statistical Manual of Mental Disorders-IV are lower and suggest that 12% of female and 5% of male adolescents are depressed (5). Previous research has examined whether body weight is a risk factor for depression among all adolescents and among female adolescents in particular, because obesity is a stigmatized status that can lead to social isolation and discrimination (6, 7). These studies have produced mixed findings (8). Among clinical adolescent samples, obesity is a risk factor for depression (9–11). Among representative national and community samples of adolescents, obesity is generally not associated with depression (12, 13), especially in studies that adjust estimates for confounders (14, 15). Even longitudinal studies that examine how adolescent obesity at baseline predicts depression 1 year later produce modest (16) or null (12) findings. Although representative studies have found little evidence that obesity is a risk factor among all adolescents, this relationship has been found among national samples of younger adolescents. Studies have found that, among students in 7th and 8th grades, body mass index (BMI) (weight (kg)/height (m)2) was associated with depression (17), and that, among children aged 12–14 years, those who were classified as obese or overweight according to age- and sex-specific BMI percentiles were also at greater risk of depression (15). Weight gain during pubertal development has also been associated with depression among adolescent girls (18). Although these subgroups are slightly different, they are all samples of younger adolescents who are in the process of transitioning from childhood to adolescence. In sum, prior research suggests that weight is not a risk factor for depression among all adolescents. Instead, it is a risk factor during the transition into adolescence. Previous studies have not examined whether weight is also associated with depression as young people transition out of adolescence, a life course stage commonly referred to as the “transition to adulthood” (19). During this time, young people undergo many life changes, including high school exit and entrance into the labor force or postsecondary educational institutions (18). Young women are also more likely than their male peers to exit parental residences, enter cohabiting and marital unions, and become parents (20). Weight gain and continued obesity in the midst of these transitions may be particularly stigmatizing and distressing because these life events place young women in new social settings and networks at a time when social relationships undergo extensive transformation (21). This leads us to hypothesize that obesity and weight gain may be associated with depression as young women transition to adulthood. To our knowledge, this is the first study to assess whether weight and weight change during the transition to adulthood influence the development of, recovery from, and “consistent” depression measured at 2 distinct time points.