Associations between unemployment and major depressive disorder: evidence from an international, prospective study (the predict cohort).

Unemployment is known to be associated with poor mental health, but it is not clear how strongly unemployment leads to onset of diagnosed clinical depression (causation), or if depression raises the risks of becoming unemployed (health selection), or indeed if both pathways operate. We therefore investigate the direction of associations between clinical depression and unemployment in a cross-cultural prospective cohort study. 10,059 consecutive general practice attendees (18-75 years) were recruited from six European countries and Chile between 2003 and 2004 and followed up at six, 12 and (in a subset) 24 months. The analysis sample was restricted to 3969 men and women who were employed or unemployed and seeking employment and had data on depression measures. The outcomes were depressive episodes, assessed using the Depression Section of the Composite International Diagnostic Interview (CIDI) and self-reported employment status. Among 3969 men and women with complete data on depression and unemployment, 10% (n = 393) had depression symptoms and a further 6% (n = 221) had major depression at 12 months. 11% (n = 423) of the sample were unemployed by 6 months. Participants who became unemployed between baseline and 6 months compared to those employed at both times had an adjusted relative risk ratio for 12-month depression of 1.58 (95% Confidence Interval 0.76, 3.27). Participants with depression at baseline and 6 months compared to neither time had an odds ratio for 6-month unemployment of 1.58 (95% Confidence Interval 0.97, 2.58). We found evidence that causation and (to a lesser extent) health selection raise the prevalence of depression in the unemployed. Unemployed adults are at particular risk for onset of major clinical depression and should be offered extra services or screened. Given the trend for adults with depression to perhaps be at greater risk of subsequent unemployment, employees with depressive symptoms should also be supported at work as a precautionary principle.

Polymorphic variation at the serotonin 1-A receptor gene is associated with comorbid depression and generalized anxiety.

BACKGROUND: Serotonin 1-A receptors are key regulators of serotonin activity and their dysregulation might be implicated in the emergence of both major depression (MD) and generalized anxiety disorder (GAD). Previous studies have yielded inconclusive results as to whether the 5-HT1A receptor gene (HTR1A) has a role in the aetiology of MD and no study up to date has analysed this polymorphism on either pure MD or MD comorbid with GAD. METHODS: In this study, 1059 patients taking part in the PREDICT-Gene study were ascertained for Diagnostic and Statistical Manual of Mental Disorders-IV MD and GAD diagnoses using the Composite International Diagnostic Interview and the Primary Care Evaluation of Mental Disorders questionnaire, respectively. They were also genotyped for the C(-1019)G functional polymorphism at the promoter region of HTR1A gene. RESULTS: Genetic variability at HTR1A was significantly associated with MD [odds ratio (OR) = 1.67; 95% confidence interval (CI) = 1.14-2.44; P = 0.008], although this effect disappeared after adjusting for GAD (OR = 1.43; 95% CI = 0.96-2.14; P = 0.080). Similarly, a crude association between C(-1019)G polymorphism and GAD was found (OR = 2.54; 95% CI = 1.28-4.86; P = 0.003), but these results became no longer significant after adjusting for MD (OR = 1.97; 95% CI = 0.99-3.91; P = 0.050). However, a main effect of HTR1A G(-1019) allele on comorbid MD-GAD was found (OR = 3.41; 95% CI = 1.44-8.05; P = 0.005) and it remained robust and statistically significant after adjusting by sex, age and family history of psychological problems (OR = 2.82; 95% CI = 1.18-6.77; P = 0.020). CONCLUSION: In our study, the HTR1A C(-1019)G polymorphism was found to be associated to the frequent clinical presentation of comorbid MD and GAD, suggesting a common genetic background for mixed depression and anxiety states. These findings should be considered as preliminary. Future replications in independent samples would be needed to confirm or discard such association.