Are the vulnerability effects of personality and psychosocial functioning on depression accounted for by subthreshold symptoms?

Previous studies could not evaluate adequately the extent to which deviant levels of personality measures and psychosocial functioning found before and after a major depressive episode (MDE) should be attributed to subthreshold depressive symptoms. Our aim is to investigate whether pre- and post-MDE personality alterations and psychosocial disability truly reflect vulnerability, or whether they can be accounted for by the presence of subthreshold depressive symptoms. Data were derived from the Netherlands Mental Health and Incidence Study, a prospective general population study with three waves. Psychopathology was measured with the Composite International Diagnostic Interview (CIDI). Course of depressive symptoms was assessed with the Life Chart Instrument in a cohort of 195 respondents with a new or recurrent MDE between waves 2 and 3. Personality and psychosocial functioning were assessed with, respectively, four and two different measures. Alterations in measurements of personality and psychosocial functioning were present before onset and after remission of an MDE. Most pre- and postonset alterations occurred in the presence of subthreshold depressive symptoms. But even without these subthreshold symptoms, some alterations in measurements of personality and psychosocial functioning were found before and after an MDE. Depressive complaints between waves 2 and 3 were retrospectively assessed, and only a limited set of brief questionnaires was used to assess personality styles and psychosocial functioning. It is unlikely that the pre- and post-MDE alterations in personality and psychosocial functioning observed in earlier studies are entirely due to subthreshold depressive symptoms. This suggests that a depressive episode is interwoven in a long-standing and enduring pattern of mild personality deviance and limitations in psychosocial functioning.