Overview
The paper is a systematic review and meta-analysis addressing gut-brain interactions that may drive relationships between depression, anxiety, and adverse health outcomes (measured as, for example, escalation of therapy, hospitalization, emergency department visits) in patients with inflammatory bowel disease (IBD). The authors reviewed papers that reported either relationships of mood symptoms with worsening IBD, or relationships between IBD symptoms and occurrence or worsening of mood symptoms.
The findings reinforce the concept of gut-brain interaction, in that baseline anxiety and depression symptoms predicted adverse health outcomes, supporting a role of top-down influence on IBD. They also found that clinically active disease at baseline predicted the development of anxiety and/or depression, supporting a bottom-up influence on mood.
Why is this important?
Whereas scientists and practitioners have accepted the idea that interactions between the gut and the brain are bidirectional for Functional Bowel Disorders (now called Disorders of Gut Brain Interaction) for nearly twenty years, this idea has been slower to permeate the world of IBD. The use of the meta-analysis, including multiple studies, allows the authors to provide a more convincing story than the results of just one study would.
So, overall, the study re-enforces the idea that what is happening in the gut links to brain functions including regulation of mood. Similarly, factors that drive mood symptoms, such as stress, are pathophysiologically important for outcomes in IBD.
Take home message
Treatment approaches for inflammatory bowel diseases need to address both gut and brain. This means that lifestyle factors, such as diet, that can influence IBD symptoms16 may also influence mood. Similarly, medical approaches to IBD, including drugs and surgery, may be enhanced with interventions targeted towards psychological resilience. Thus, the best outcomes are likely to follow form targeting both bottom-up and top-down gut and brain-related factors