Severity of stressful life events in first and subsequent episodes of depression: the relevance of depressive subtype

BACKGROUND: Recent studies have reignited debate concerning the relationship between stressful life events and depressive subtypes, particularly in relation to first versus subsequent episodes. AIMS: To investigate the relationship between stressful life events and variably defined melancholic/non-melancholic depressive subtypes, and the import of such life events to first compared with subsequent episodes across those subtypes. METHOD: Acute and chronic stressful life events were rated in 270 patients with DSM-IV Major Depressive episodes who were allocated to melancholic and non-melancholic groups separately as defined by DSM-III-R, DSM-IV, the Newcastle criteria and the CORE system. RESULTS: Severe stressful life events (both acute and chronic)-as defined by DSM-III-R axis IV-were more likely to occur prior to first rather than subsequent episodes, particularly for those with non-melancholic depression. LIMITATIONS: Dependence or independence of life events was not assessed. Genetic vulnerability to depression was not determined. Life events in first and subsequent depressive episodes were compared cross-sectionally between groups, not prospectively in the same cohort of patients. There were no differences in the number of severe life events-as defined by clinician consensus-between the first and subsequent episodes. CONCLUSIONS: These findings are consistent with other studies in suggesting an enhanced sensitisation of depressed patients to subsequent episodes of depression, but suggest that any such phenomenon is specific to non-melancholic depression, in comparison to one key previous study.