Depression, Stress and the Risk of Heart Disease
Depression, Stress and the Risk of Heart Disease
Psychiatric Times October 2005
In recent years, depression has emerged in the discussion of the impact of psychological aspects on risk of heart disease. Several prognostic studies have shown that depression is a predictor for mortality after acute myocardial infarction (AMI) (Frasure-Smith et al., 1995a, 1993) and the risk is directly related to the severity of mood symptoms: a one- to twofold increase in coronary heart disease (CHD) for minor depression and a three- to fivefold increase for major depression (Bunker et al., 2003).
Extensive longitudinal data suggest that depression may also precede the development of CHD; however, whether depression has an impact on such development in initially healthy individuals is less clear and drawing conclusions from studies investigating the association between depressive symptomatology and CHD has been limited by the various criteria and methods used to define both clinical and subsyndromal depression. These diverse methods include self-report, clinical diagnosis and symptom checklist (Littman, 1998).
One aspect of depression, hopelessness, has received particular attention. Prospective epidemiological studies have also reported a relationship between symptoms of hopelessness and the development of CHD through carotid atherosclerosis (Everson et al., 1997, 1996). A related phenomenon is vital exhaustion: Appels and Mulder (1988) found that this state--characterized by unusual fatigue, increased irritability and demoralized feelings--is associated with an increased risk of AMI.
Moreover, a large number of investigations have suggested a role for stressful life events in uncovering an individual's vulnerability to acute CHD (Mayou, 1979; Reich, 1983). A life event represents a discrete change in an individual's social or personal environment, which should be external and verifiable rather than internal or psychological. The use of structured methods of data collection has indicated that stressful life events were significantly more frequent in patients with AMI compared to control groups (Magni et al., 1983). While the link between stressful life events and the onset of depression has been well documented, the relationship between recent life events (evaluated by observer interview), clinical and subsyndromal depression (observer rated and clearly defined by diagnostic criteria), and the onset of a first episode of AMI has been less investigated.
Rafanelli and colleagues (2005), in a case-controlled study, evaluated the presence of major and minor depression, recurrent depression, demoralization and stressful life events in the year preceding the first occurrence of AMI and/or a first episode of instable angina and compared stressful life events also related with mood disorders in 97 patients and 97 healthy participants. The following measures were used: 1) Structured Clinical Interview for DSM-IV Axis I Diagnosis (SCID-I) for determining major and minor depression diagnoses; 2) semi-structured interview for new Diagnostic Criteria in Psychosomatic Research (DCPR) (Rafanelli et al., 2003), which identifies the subclinical psychological syndrome of demoralization (Table 1) (Due to copyright concerns this Table cannot be reproduced online. Please see p37 of the print edition--Ed.); and 3) Paykel's (1997) Interview for Recent Life Events (IRLE) to detect 64 life events clustered in 10 areas: employment, education, financial status, somatic health, loss/bereavement, relocation, courtship/relationships, legal, family and social problems, and marital conflicts. The IRLE also identifies the quality of events such as the objective negative impact (i.e., the judgment of the expected stressfulness of the event when its full nature and particular circumstances are taken into account, ignoring the subjective reaction of the patient) and independence (i.e., the likelihood that the event is not a consequence of the psychological or physical states of the patient). It considers three categories of events: 1) entrances (involving introduction of new people, such as marriage) and exits (involving departure of a person from the social field of the patient, such as the death of a close family member); 2) socially desirable (e.g., promotion) or undesirable (e.g., major financial problems) events; and 3) controlled events (when the initiation of the event was likely to be under the individual's control or choice) or uncontrolled events (not likely to be under individual's control or against one's wish).
In this study, 30% of patients were suffering from one or more episodes of major depression (Rafanelli et al., 2005). Within this group, less than half of the patients (n=13) suffered from recurrent depression. Nine percent of the total sample were suffering from minor depression and 20% from demoralization. In 12% of patients there was an overlap between major depression and demoralization (Table 2). Moreover, patients reported significantly more life events (129 versus 21), independent and with negative impact, than controls (p(Due to copyright concerns this Table cannot be reproduced online. Please see p37 of the print edition--Ed.). All categories of events, except entrances, were more frequent in patients than in healthy controls (Table 4) (Due to copyright concerns this Table cannot be reproduced online. Please see p37 of the print edition--Ed.). The most frequent events in the CHD group occurred in the following areas: loss/bereavement (25%), somatic health (19%), employment (16%), family problems (12%), legal problems (10%) and financial problems (9%). See Table 5 for more detailed events.