Life satisfaction and depression in a 15-year follow-up of healthy adults

Objective The aim of this study was to investigate the cross-sectional and longitudinal relationship between life satisfaction and depressive symptoms in healthy adults. Method This is a 15-year prospective cohort study with a nationwide sample of healthy Finnish adults (N=9679), aged 18–45,who responded to postal questionnaires in 1975, 1981 and 1990 including a 4-item life satisfaction (LS) scale (range 4–20) and, in 1990, the 21-item Beck Depression Inventory (BDI). Results A strong linear association was found between concurrent LS and BDI scales (r=0.6).With an LS cut-off point of 11/12, moderate/severe depression (BDI ≥ 19) was detected with 87% sensitivity, 88 % specificity and a 94% area under the ROC curve. Longitudinally, a strongly increased risk of moderate/severe depression in 1990 was observed among the dissatisfied (LS 12–20) compared with the satisfied (LS 4–6) in 1975 (OR=6.7; 95%CI 4.2–10.9) and in 1981 (OR=10.4; 6.1–17.6). Conclusion The 4-item LS scale can identify a group of healthy people from the general population with a high risk of having or developing depressive symptoms.Since low life satisfaction also indicates an elevated risk of other adverse health outcomes, the assessment of subjective well-being should be encouraged both in surveys and in clinical practice.