Depression following myocardial infarction: first-ever versus ongoing and recurrent episodes

Abstract

Background

Depression following myocardial infarction (MI) can be a first-ever episode for some, whereas for others, it may represent a recurrent episode or one that was present at the onset of the infarction. We investigated if there are differences in pre- and post-MI characteristics between these subtypes.

Methods

Four hundred sixty-eight patients admitted for an MI were assessed for the presence of an ICD-10 depressive disorder following MI. A comparison was made between first-ever and ongoing or recurrent depression on demographic and cardiac data, personality, and depression characteristics.

Results

Depressive disorder during the first post-MI year was present in 25.4% of the MI patients (n=119), and almost half were ongoing or recurrent (n=53, 44.5%). Recurrent and ongoing depression was related to high neuroticism (Z=2.77, P<.01), whereas first-ever depression was associated with MI severity (poor left ventricular ejection fraction: Z=1.64, P=.05; PTCA or CABG during hospitalization: Z=1.88, P=.03; arrhythmic events: Z=1.49, P=.06).

Conclusions

Our results suggest that in the first-ever post-MI depression cases, depression may be triggered by the severity of the MI, whereas ongoing and recurrent depression is more related to personality. Future research should address the question whether these subtypes of depression differ in cardiovascular prognosis and response to psychiatric treatment.

Introduction

Depression following myocardial infarction (MI) is a highly prevalent disorder with a negative effect on cardiac prognosis [1], [2], [3], [4], [5], [6]. In about half of the cases, patients have experienced a depressive episode already before the onset of the MI [7], [8], [9]. From a clinical perspective, a distinction between two types of post-MI depression may be of interest: a post-MI depressive episode in patients who have never been depressed before (incident depression) versus a depression that was present at the time of the MI or already before (nonincident depression). Little is known about the etiology and characteristics of these two types, and as a result, it remains unknown to what extent post-MI depression should be considered a transient distress reaction to a life-threatening event or a resurfacing of a preexisting depressive vulnerability.

In two small studies, incident post-MI depression was compared to nonincident depression. Freedland et al. [8] found that 17 out of 39 post-MI depressed patients who had a history of depression (43.6%) had more severe depression and less severe coronary artery disease compared to those with an incident depression. Lloyd and Cawley [7] distinguished between 16 post-MI depressed patients who had a depressive history (45.7%) and 19 post-MI depressed patients without a depressive history (52.8%). Although the latter group of incident depression cases resembled a psychologically healthy control group, patients with a depression that existed already before the MI had significantly higher neuroticism scores. Moreover, the depressive symptoms of patients with an incident post-MI depression tended to be transient and improved without psychiatric treatment.

These findings may be explained from a perspective of stress and vulnerability. In psychologically healthy subjects, the stress resulting from a severe MI may be the main reason for them to develop a depressive episode. For subjects with a history of depression before the MI, however, a high level of neuroticism may be the reason, whereas the level of the trigger — the MI — may be of less importance. In order to clarify potential differences between these two groups, we set out to describe risk factors and characteristics of post-MI depression, comparing incident post-MI depressions and nonincident post-MI depressions. We hypothesized that incident depression was associated with a more severe MI, whereas nonincident depression was associated with neuroticism.