Can we predict future depression in residents before the start of clinical training?

CONTEXT: Depression among medical residents is a very serious problem. It is, however, very difficult to detect signs of depression early, despite the severity and frequency of depression. We designed a nationwide longitudinal study to investigate whether the Sense of Coherence (SOC) Scale, an indicator of ability to cope with stress, could predict future depressive symptoms among medical residents. METHODS: We distributed self-administered questionnaires to first-year residents in 251 postgraduate education hospitals just before the start of their clinical training. The questionnaire contained the Center for Epidemiologic Studies Depression (CES-D) Scale (a screening tool for depression), the SOC Scale, and items on demographic factors. After 3 months, we again distributed questionnaires to residents who had responded to the first survey. The second questionnaire contained the CES-D Scale and items on the respondents' working conditions. We categorised respondents into three groups according to their SOC scores and analysed the relationships between the three SOC groups (low, middle and high scores) and the occurrence of depressive symptoms at the follow-up survey. RESULTS: In all, 1738 of 2935 residents (59.2%) responded to the first survey. Of these, 1245 residents (71.6%) also responded to the follow-up survey. A total of 189 residents were excluded because they screened positive for depressive symptoms at the first survey. Data for a further 36 were excluded because they were incomplete. At the follow-up survey, 238 of the remaining 1020 residents (23.3%) had new-onset depressive symptoms. These included 61 (41.2%) respondents in the low SOC group, 159 (22.3%) in the middle SOC group, and 18 (11.3%) in the high SOC group (p < 0.01). The odds ratio of the low SOC group for new-onset depressive symptoms, adjusted for demographic factors, baseline CES-D score and mean working time, was 3.11 (95% confidence interval 1.48-6.53), using the high SOC group as the reference. CONCLUSIONS: The SOC score was significantly related to future depressive symptoms among medical residents. The SOC Scale might be a useful and easy-to-use predictor of future depression.