UCLA

Background

Stress precipitates depression and may do so in part by increasing susceptibility to inflammation-induced depressive symptoms. However, this has not been examined among individuals facing a major life stressor. Accordingly, the present study tested the moderating role of stress on the longitudinal association between inflammation and depressive symptoms among women with breast cancer.

Methods

Women recently diagnosed with early-stage breast cancer (N = 187) were enrolled before starting adjuvant/neoadjuvant treatment. Blood draws and self-reported depressive symptoms were collected pre-treatment, post-treatment, and at 6, 12, and 18-month post-treatment follow ups. C-reactive protein (CRP) was used to index inflammation. Measures of psychological stress, including cancer-related stress, general stress perceptions, and childhood stress, were administered pre-treatment.

Results

Stress moderated the association between CRP and depressive symptoms, such that higher levels of CRP were associated with elevated depressive symptoms only among women who reported high cancer-related stress (β = 0.080, p = .002) and perceived stress (β = 0.053, p = .044); childhood stress effects were non-significant. Moreover, elevated CRP was associated with increased odds of exhibiting clinically significant depressive symptoms (OR = 1.64, p < .001) among women who reported high cancer-related stress. Results were independent of age, BMI, race and cancer-related covariates.

Conclusions

Stress was found to heighten sensitivity to inflammation-associated depressive symptoms over a 2-year period, with notably stronger effects for subjective stress responses to a concurrent life event. Individuals who are most distressed following a major life event may exhibit the greatest risk for inflammation-induced depression.