Depression and inflammation fuel one another. Inflammation plays a key role in depression's pathogenesis for a subset of depressed individuals; depression also primes larger cytokine responses to stressors and pathogens that do not appear to habituate. Accordingly, treatment decisions may be informed by attention to questions of how (pathways) and for whom (predispositions) these links exist, which are the focus of this article. When combined with predisposing factors (moderators such as childhood adversity and obesity), stressors and pathogens can lead to exaggerated or prolonged inflammatory responses. The resulting sickness behaviors (e.g., pain, disturbed sleep), depressive symptoms, and negative health behaviors (e.g., poor diet, a sedentary lifestyle) may act as mediating pathways that lead to further, unrestrained inflammation and depression. Depression, childhood adversity, stressors, and diet can all influence the gut microbiome and promote intestinal permeability, another pathway to enhanced inflammatory responses. Larger, more frequent, or more prolonged inflammatory responses could have negative mental and physical health consequences. In clinical practice, inflammation provides a guide to potential targets for symptom management by signaling responsiveness to certain therapeutic strategies. For example, a theme across research with cytokine antagonists, omega-3 fatty acids, celecoxib, and exercise is that anti-inflammatory interventions have a substantially greater impact on mood in individuals with heightened inflammation. Thus, when inflammation and depression co-occur, treating them in tandem may enhance recovery and reduce the risk of recurrence. The bidirectional links between depression, inflammation, and disease suggest that effective depression treatments could have a far-reaching impact on mood, inflammation, and health.

Objectives Cancer survivors often report cognitive problems. Furthermore, decreases in physical activity typically occur over the course of cancer treatment. Although physical activity benefits cognitive function in non-cancer populations, evidence linking physical activity to cognitive function in cancer survivors is limited. In our recent randomized controlled trial, breast cancer survivors who received a yoga intervention had lower fatigue and inflammation following the trial compared to a wait-list control group. This secondary analysis of the parent trial addressed yoga’s impact on cognitive complaints. Methods Post-treatment stage 0 – IIIA breast cancer survivors (N = 200) were randomized to a 12-week twice-weekly Hatha yoga intervention or a wait-list control group. Participants reported cognitive complaints using the Breast Cancer Prevention Trial (BCPT) Cognitive Problems scale at baseline, immediately post-intervention, and 3-month follow-up. Results Cognitive complaints did not differ significantly between groups immediately post-intervention (p = .250). However, at the 3-month follow-up, yoga participants’ BCPT Cognitive Problems scores were an average of 23% lower than wait-list participants’ scores (p = .003). These group differences in cognitive complaints remained after controlling for psychological distress, fatigue, and sleep quality. Consistent with the primary results, those who practiced yoga more frequently reported significantly fewer cognitive problems at the 3-month follow-up than those who practiced less frequently (p < 0.001). Conclusions These findings suggest that yoga can effectively reduce breast cancer survivors’ cognitive complaints, and prompt further research on mind-body and physical activity interventions for improving cancer-related cognitive problems.

Women become depressed more frequently than men, a consistent pattern across cultures. Inflammation plays a key role in initiating depression among a subset of individuals, and depression also has inflammatory consequences. Notably, women experience higher levels of inflammation and greater autoimmune disease risk compared to men. In the current review, we explore the bidirectional relationship between inflammation and depression and describe how this link may be particularly relevant for women. Compared to men, women may be more vulnerable to inflammation-induced mood and behavior changes. For example, transient elevations in inflammation prompt greater feelings of loneliness and social disconnection for women than for men, which can contribute to the onset of depression. Women also appear to be disproportionately affected by several factors that elevate inflammation, including prior depression, somatic symptomatology, interpersonal stressors, childhood adversity, obesity, and physical inactivity. Relationship distress and obesity, both of which elevate depression risk, are also more strongly tied to inflammation for women than for men. Taken together, these findings suggest that women’s susceptibility to inflammation and its mood effects may contribute to sex differences in depression. Depression continues to be a leading cause of disability worldwide, with women experiencing greater risk than men. Due to the depression-inflammation connection, these patterns may promote additional health risks for women. Considering the impact of inflammation on women’s mental health may foster a better understanding of sex differences in depression, as well as the selection of effective depression treatments.