Significance of prior episodes of depression in two patient populations.

Perhaps the single best predictor of current depression is a prior episode of depression. This study examined the significance of prior depressive episodes in a weighted sample of 425 primary medical care (PC) patients. It also compared the 53 PC patients with major depression with 93 depressed psychiatric patients with respect to percentage of recurrences versus 1st episodes. PC patients with prior depression were over 8 times more likely to be currently depressed than those without such a history. Having at least 1 prior episode of depression was modestly more sensitive, but less specific, than an elevated Center for Epidemiologic Studies--Depression Scale score in predicting current depression. Most currently depressed patients in both PC (85%) and psychiatry (78%) had prior episodes of depression. These findings highlight the importance of assessing history of depression in research and clinical practice.