Depression, which affects about 2-3% of men and 4-9% of women at any one point in time and up to 20% of individuals during their lifetime, [1,2] is a major public health problem. According to the World Bank and the World Health Organization, depressive disorder is currently the fourth leading cause of disability worldwide and may become second by 2020 .
Despite the availability of effective treatment, 50-70% of depression cases persist over time (that is become chronic or recurrent) [4,5]. Factors associated with depression persistence include negative life events (ex. divorce, death of a loved one, employment loss), lack of adequate treatment, initial symptom severity, or presence of a chronic illness . Additionally, depression course may vary with individuals’ socioeconomic characteristics; however findings in this area have been mixed [7-18]. This may be due to methodological differences between prior studies: 1) some studies were conducted in clinical populations [11,12,14,19], 2) some had limited statistical power, [8,17,18] 3) in some depression course was assessed retrospectively [13,14], 4) measures of socioeconomic position varied from parental socioeconomic position , education level [7,9,14,18], individual income  to individual occupational grade [9,15].
A prior report from the GAZEL cohort based on a subsample of 298 participants in whom depression was assessed with a standardized diagnostic interview and followed for 7 years, suggested that individuals with low socioeconomic position were more likely to experience persistent depression. However, this study had limited statistical power and did not account for a number of relevant covariates . Another investigation based on the entire GAZEL cohort study sample suggested the existence of a socioeconomic gradient with regard to depression trajectories, and particularly persistent symptoms. However, this study did not account for factors that can influence depression course over time . The present analysis addresses the concerns risen by these two prior studies, by examining the relationship between occupational grade and depression course in 3,368 GAZEL study participants followed prospectively over up to 12 years, and controlling for factors potentially associated with occupational grade and depression measured at baseline and during follow-up (demographic characteristics including retirement status, social networks, negative life events, health behaviors, chronic illnesses including prior depression, Use of antidepressants).
Citation: Yaogo A, Chastang JF, Goldberg M, Zins M, Younès N, et al. (2012) Occupational Grade and Depression Course in a Non-Clinical Setting: Results from the French GAZEL Cohort Study. J Depress Anxiety 1:111. doi: 10.4172/ 2167-1044.1000111