Moderation of the time-to-onset of depression by depression history

A considerable body of evidence suggests that life stress is related to the onset and course of depression. People who become depressed following a severe life event, however, vary greatly in the time-to-onset of their depressions, with some meeting and maintaining depression symptom criteria within days or weeks of experiencing a life event and others not meeting symptom or diagnostic criteria for several months. Few data exist, however, that describe and elucidate the interval of time between a severe life event and the onset of depression, the factors that may influence the interval, the implication interval variance may have for treatment considerations, and what such variation may reveal about a primary hypothesis of depression Ì¢‰âÂ' the kindling hypothesis. Since a history of depressive episodes is one of the strongest predictors of future episodes of depression, the present study examined the association of depression history (i.e., first episode versus recurrence) and the time-to-onset of depression following a severe life event. This approach permitted an evaluation of stress sensitization, a premise derived from the kindling hypothesis, which suggests that people who are 'kindled' or sensitized by previous episodes of depression should succumb to depression more quickly than people without a history of depression. The results indicate that depression history alone is not predictive of the time-to-onset of depression following a severe life-event. Post-hoc analyses were conducted to examine two potential moderators of the time-to-onset of depression, allelic variation in the serotonin transporter gene and the focus of severe life events. Both variables moderated the time-to-onset of depression following a severe life event.