Major depression before and after myocardial infarction: its nature and consequences.

The prevalence and prognostic impact of previous depression, depression in the hospital, and depression after discharge were studied in 222 patients admitted for acute myocardial infarction (MI). Patients were interviewed 1 week, 6 months, and 12 months after the index MI using a modified version of the Diagnostic Interview Schedule (DIS); patients also completed the Beck Depression Inventory (BDI). Patients or family members were recontacted at 18 months to determine survival. Some 27.5% of patients had at least one episode of major depression before their MI, but only 7.7% were depressed at some point during the year preceding the infarct. Overall, 31.5% of patients experienced depression in the hospital or during the year postdischarge. Some 35 patients were depressed in the hospital, 30 became depressed between discharge and 6 months, and five more between 6 and 12 months after the MI. History of depression increased the risk of depression in the hospital and after discharge. Depression in the hospital was associated with an increased risk of mortality over 18 months. Patients who experienced a recurrent depression in the hospital were at particularly high risk. Although patients who became depressed after discharge differed from those who remained depression-free in terms of age, history of depression, BDI scores, and the number of depression symptoms on the DIS in the hospital, a model including these variables identified only 14.7% of the patients who became depressed after returning home. Post-MI depression is common and largely unrelated to medical and psychosocial factors.