Traumatic event exposure and depression severity over time: results from a prospective cohort study in an urban area

A substantial proportion of adults experience traumatic events each year, yet little is known about the effects of different types of traumatic events on depression severity over time. We prospectively assessed the effects of traumatic event exposure during a 1-year period on changes in depression severity during that period among a representative sample of adults living in Detroit, Michigan in the United States.

We used data from 1,054 participants in the first two waves of the Detroit Neighborhood Health Study (2008-2010). Depression severity was measured with the Patient Health Questionnaire-9 (PHQ-9). Negative binomial regression was used to estimate the effect of traumatic event exposure on depression severity at Wave 2, adjusting for Wave 1 PHQ-9 score and potential confounders.

The mean depression severity score at Wave 2 among those exposed to at least one traumatic event during follow-up was 1.71 times higher than among those with no traumatic event exposure [95 % confidence interval (CI) 1.27-2.29]. Also positively associated with depression severity at Wave 2 (vs. no traumatic events) were assaultive violence (mean ratio 2.49, 95 % CI 1.41-4.38), injuries and other directly experienced shocking events (mean ratio 2.59, 95 % CI 1.62-3.82), and three or more traumatic events (mean ratio 2.58, 95 % CI 1.62-4.09).

Violence, injuries, and other directly experienced traumatic events increase depression severity and may be useful targets for interventions to alleviate the burden of depression in urban areas.