The majority of studies on the mental health predictors, correlates and outcomes associated with CVD focus on major depression, and subclinical measures of depression symptoms. Epidemiologic studies with state of the art sampling and measurement of CVD typically include only depression symptom scales, and sometimes structured interviews used to identify diagnoses of depression, but do not usually assess anxiety disorders (Haines et al., 1987
; Barlow 1988
; Stansfeld et al., 2002
; Kubzansky et al., 2006
). The current data suggest that anxiety disorders are strongly and significantly associated with CVD among adults in the United States, and that this relationship persists independent of the influence of depressive disorders. As such, our results provide preliminary evidence suggesting that a range of mental disorders, including anxiety disorders, should be assessed when attempting to understand the role of depression in CVD prevalence, incidence, and recurrence. Our results also suggest that there is a significant relationship between having any mood disorder and CVD among adults in the community, which persists after adjusting for anxiety disorders. Yet, the link between major depression specifically and CVD, or other specific mood disorders, was no longer significant after adjusting for anxiety disorders, suggesting that failure to evaluate both mood and anxiety disorders when examining the relationship between mental disorders and CVD may obscure potentially important relationships.
These data have limitations in the assessment of CVD. Specifically, CVD diagnosis is by self-report of a physician diagnosis. Sensitivity (98%) and specificity (99.3%) has recently been reported for the comparison of self-report of myocardial infarction (MI) to verified hospital records (Meisinger et al., 2004
). Further, where patients mis-reported an MI, they most typically had a documented cardiovascular event, and so would still meet our case definition. Similarly, in Minnesota Heart Health participants, documentation of MIs existed for 60% of those reporting a physician diagnosis of MI, and almost half of the other 40% had cardiac hospitalizations (for congestive heart failure, cardiac procedures, and coronary insufficiency)(Rosamond et al., 1995
). Thus, a self-report of CVD physician diagnosis is ideal for epidemiological studies of over 40,000 persons, but does not provide much detail in terms of severity or specific type of event, and still leaves report bias a possibility. As anxiety and depression are associated with over-reporting of medical symptoms (Katon et al., 2007
), there is potential confounding in our study. We acknowledge this limitation in our large epidemiologic study but do not believe that sensitivity and specificity would fall to unacceptable levels because of selective reporting by anxious patients.
Whether anxiety disorders are implicated in the incidence or recurrence of CVD is currently unknown, as most previous studies testing this association employ self-reported subclinical anxiety symptoms, rather than anxiety disorder diagnoses (Haines et al., 1987
; Barlow, 1988
; Paterniti et al., 2001
; Stansfeld et al., 2002
). Whether or to what degree our positive association between anxiety disorders and CVD suggests that adjustment for anxiety disorders in previous associations found between depression and CVD incidence and recurrence would alter their conclusions is also not known (Kapfhammer, 2006
). Without studies that use state-of-the-art, diagnostic measures for both physical and mental health problems in the same population-based study, it will not be possible to answer these questions. As the disparity between our results and the majority of previous studies of major depression and CVD indicates, funding gold standard measures for only one part of an association could result in erroneous conclusions.
Even very recently published studies of the association of anxiety and CVD incidence/recurrence continue to employ self-report measures of anxiety symptoms such as MMPI or MMPI-2 scores, rather than anxiety disorder diagnostic assessments (Kubzansky et al., 2006
; Rothenbacher et al., 2007
; Shen et al., 2008
). Interestingly, in all three of these smaller, but prospective studies, anxiety symptoms uniquely predict CVD incidence or recurrence, over conventional factors and depressive symptoms. What remains to be answered is if the same unique CVD contribution exists for anxiety disorders, over depressive disorders, when these and CVD are assessed by gold standard measures.