Natural course of recurrent psychological distress in adulthood.

BACKGROUND: The course of major depressive disorder is often characterized by progressing chronicity, but whether this applies to the course of self-reported psychological distress remains unclear. We examined whether the risk of self-reported psychological distress becomes progressively higher the longer the history of distress and whether prolonged history of distress modifies associations between risk markers and future distress.
METHODS: Participants were British civil servants from the prospective Whitehall II cohort study (n=7934; 31.5% women, mean age 44.5 years at baseline) followed from 1985 to 2006 with repeat data collected in 7 study phases. Psychological distress was assessed with the 30-item General Health Questionnaire (GHQ). Sex, socioeconomic status, marital status, ethnicity, physical activity, alcohol consumption, smoking, and obesity were assessed as risk markers.
RESULTS: Recurrent history of psychological distress was associated with a progressively increasing risk of future distress in a dose-response manner. Common risk markers, such as low socioeconomic status, non-White ethnicity, being single, and alcohol abstinence, were stronger predictors of subsequent distress in participants with a longer history of psychological distress. Sex differences in psychological distress attenuated with prolonged distress history. LIMITATIONS: The participants were already adults in the beginning of the study, so we could not assess the progressive chronicity of psychological distress from adolescence onwards.
CONCLUSIONS: These data suggest that self-reported psychological distress becomes more persistent over time and that a longer prior exposure to psychological distress increases sensitivity to the stressful effects of certain risk markers.