The importance of depression following myocardial infarction.

Depressive disorder, as defined by standardised research criteria, is recorded in 13–19% of patients at the time of myocardial infarction (MI). 1–7 The disorder is important in MI patients because depression is associated with several adverse outcomes: increased mortality, 1 5–7 angina, 2 arrhythmias, 2 6 8 rehospitalisation, prolonged disability, and continued smoking. Increased mortality There is increasing evidence that depressed myocardial infarction patients have an increased mortality rate 1–6 ; this eVect appears to be independent of the severity of MI and is impressive. In the most quoted study, examining six month mortality, patients with major depression had an increased mortality rate: after adjusting for other factors (previous MI, age and Killip class) the adjusted hazard ratio was 3.3 (95% confidence intervals (CI) 1.96 to 4.68). 1 At 18 months' follow up the adjusted odds ratio was 6.6 for patients who had depressive symptoms shortly after the MI. 5 If these results were replicated in the UK, the increased mortality associated with depressive disorder would represent approximately 20 000 patients per annum. Severity and duration of depression The association between depression and increased mortality is derived from studies including small numbers of depressed patients, and the studies are not entirely consistent. A number of methodological diYculties must be considered , namely that studies have varied in their measures of depression, the inclusion rates of patients and the proportions of men and women (table 1). 1 2 6 9–12 All studies agree that depression in MI is independent of the severity of the infarction. Diagnosis Diagnosis of depressive disorder according to research criteria requires consistent symptoms over two weeks. It is not clear whether depressive symptoms that have only been present for 7–10 days after an MI should be regarded as depressive disorder. In addition, it appears that the presence of a few depressive symptoms (a Beck depression inventory score > 10) immediately after the infarct accurately predicts mortality at 18 months. 5 It is not clear why mild depression should be predictive of increased mortality. It is known that chronic depressive disorder (that is, occurs many months before the MI) is associated with more severe depression, more social problems, and reduced chance of stopping smoking after an MI. Social stress and depression Two studies emphasised the greatest eVect of depression on mortality among women, especially those recently divorced. 10 15 These findings concur with previous studies that show that …