Authors’ reply

We would like to thank Dogoritis and colleagues for their interest in and comments on our recent paper on the association between cardiovascular diseases and depressive symptoms.

Regardless of the differences concerning the study design and aims (an epidemiological pooled analysis of cross-sectional surveys based on a random sample of the general Polish population1 vs a clinical retrospective study including patients who underwent a single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI2), both discussed papers confirmed the existence of a relationship between depressive symptoms (DSs) and coronary artery disease (CAD). In our research, we used the term DSs, because clinical verification of a depression diagnosis based on the Beck Depression Inventory questionnaire was not possible. It is very important to obtain similar results in different populations and different research designs to confirm the association between the analyzed factors. Additionally, the use of SPECT MPI enables a very precise identification of persons with CAD (both symptomatic and asymptomatic), although the use of SPECT is possible only in clinical trials and not in epidemiological studies with a very large study population.

Depression is probably the most common and, at the same time, the most underdiagnosed mental health condition. The relationship between depression and chronic diseases, including cardiovascular diseases (CVDs), is bilateral. Of course, chronic diseases can cause DSs, but on the other hand, DSs are considered a risk factor for some conditions (like CVDs) due to emotional stress associated with the activation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis, endothelial dysfunction,3 platelet activation, and production of proinflamatory cytokines4 and also due to the impact of depression on the lifestyle.5 We fully agree with Dogoritis and colleagues that depression may represent an additional risk factor for myocardial ischemia without CAD, because depressive persons can exhibit coronary artery spasm, leading to myocardial ischemia, without coronary artery stenosis.

Because of the cross-sectional design of the 3 original studies, we analyzed the associations between DSs and CVDs, but not the cause-and-effect relationship. We showed, based on a large population sample (20 514 individuals), that even borderline DSs (10–14 points in the Beck Depression Inventory; min/max, 0/63 points) were associated with self-reported CAD, arrhythmia, and stroke, regardless of age, marital status, education, and concomitant disorders. Unlike Fotopoulos et al,2 we found a lower percentage of persons with DSs among those with CAD (approximately 41% vs 53.8%), because we only analyzed DSs, not anxiety or both. We also fully agree with Dogoritis and colleagues that the rate of CAD among depressive patients is high and therefore such patients should be monitored and screened for myocardial condition, because they are at increased risk for future cardiovascular events. On the other hand, testing for DSs among individuals with chronic diseases, especially those leading to major disability, like stroke, coronary artery disease, heart failure, or chronic obstructive pulmonary disease, is also of great importance.