Really, disease doesn't matter? A commentary on correlates of depressive symptoms in women treated for early-stage breast cancer.

Our initial response to the results reported by Bardwell et al was very odd— bordering on ironic. Here is an article that shows that objective, disease-related variables have virtually nothing to do with depressive symptoms following diagnosis and treatment for breast cancer. Rather, all of the action seems to be due to psychosocial factors, such as optimism and the lack of social support, or to the patient’s subjective response to the disease and its treatment, as indexed by ratings of pain, physical functioning limitations, and symptoms. Our immediate reaction was to ask, how can this be? Surely biomedical factors have to have some impact. So where is the irony? It derives from the fact that we are both psychologists. As such, we should have relished the findings that were reported. Yet, we were skeptical. We should be clear though about the source of our skepticism. It was not the fact that psychosocial factors were shown to be important. Of course, we knew those variables would matter. Our disbelief was in the fact that biomedical factors had virtually no effect. Our commentary is divided into two parts. In the first part, driven largely by our skepticism, we describe a couple of alternative explanations that occurred to us that may have made the findings less than definitive. We also describe efforts to gather additional information that might speak to some of the concerns we have. As will become clear, the findings do seem to hold up to careful scrutiny. Accordingly, in the second part of the commentary, we describe some of the implications that the findings have, if presumed accurate. One of our concerns had to do with the absence of an association between stage and depressive symptomatology. The problem had to do with homogeneity with respect to stage of disease. That is, the majority of women had stage I and II disease, and a small number had early stage III disease. The lack of relation between stage and depressive symptoms might have been due to the restricted range on this variable. However, one of us has data on a group of women (N 284; unpublished) diagnosed with stage I, II, and IV breast cancer. Forty percent of the women had stage I, 30% had stage II, and 30% had stage IV. Depressive symptoms were measured by a 10-item version of the Center for Epidemiologic Studies Depression Scale. The correlation between disease stage and depressive symptoms in this sample was not close to being significant (r 0.04). We were surprised by this finding. Still, the data helped to convince us that restriction of range does not provide a viable interpretation of why there was no association between disease stage and depressive symptoms in the findings reported by Bardwell et al. The absence of an association in fact seems real. A second concern had to do with the amount of time that passed since the women were diagnosed and treated. Is it possible that the lack of a relation between objective characteristics of the disease and depressive symptoms in this sample were due to the fact that patients were too distant from the initial diagnosis? Might a relation have appeared among patients who were newly diagnosed? Bardwell et al found no relation of time since diagnosis to depression, but patients in their study were diagnosed as much as 4 years earlier with the earliest group having been diagnosed during the past year. Perhaps associations between biomedical factors and depressive symptoms are very short lived and dissipate even within a 1-year period. Again, one of us has data on a large group of women (N 312; unpublished) with largely stage I (25%) and II (69%) disease who were more recently diagnosed with breast cancer (average diagnoses within 3 months) and found no relation of stage of disease, kind of surgery, or estrogen receptor status to depressive symptoms. In fact, in one article, we reported that stage of disease did not distinguish among different trajectories of mental functioning over a 4-year period. Thus, stronger relations do not emerge among newly diagnosed women, suggesting that this was not a factor in the results reported. We have offered two alternative explanations for the absence of associations reported by Bardwell et al, both of which were ruled out by examination of other data sets that were available. There are several other questions that remain that we could not resolve with recourse to additional data, and we would like to at least mention them in passing. First, although it seems clear that there are no simple associations between biomedical factors and depressive symptoms, more complex associations may exist. In this regard, it is possible that there is a synergistic relation between objective disease characteristics and psychosocial variables in predicting mental health outcomes. For example, optimism or previous life events might be more strongly related to depression among patients with more severe disease, as might be implied by a stress-diathesis model. Such a model would assume that biomedical factors are important in increasing the impact of psychosocial factors, as stress increases and passes some threshold as one moves from early to advanced disease. This possibility was not explored by Bardwell et al. Our final point concerns the manner in which treatment effects were evaluated. Specifically, although the authors examined JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 24 NUMBER 16 JUNE 1 2006