• I reviewed studies examining the hypothesis that life events may precipitate a depressive disorder. Although some contradictory results exist, the majority of studies demonstrate that depressed patients experience more stressful events in the months that precede the onset of their disorder than do normal controls or schizophrenics. In calculating relative risk figures, it seems that depressive risk is increased by a factor of about 5 or 6 for the six months after an event. Certain events, such as undesirable, loss, or severely threatening events, are particularly likely to precede a depression. These results suggest that stressful events can bring about depressive episodes, but most of the evidence that supports this conclusion emanates from retrospective studies, and corroborating prospective studies are definitely needed. Furthermore, not all depressives report precipitating events, so other causal factors are also operative.
Lloyd C. Life Events and Depressive Disorder ReviewedII. Events as Precipitating Factors. Arch Gen Psychiatry. 1980;37(5):541-548. doi:10.1001/archpsyc.1980.01780180055005