The finding: Anxiety and depression increased the risk for irritable bowel syndrome onset by two-fold. This finding is more prominent in individuals that develop IBS after a GI infection.

Strengths and weaknesses: This is a meta-analysis of 11 different papers exploring anxiety and depression as risk factors for the development of irritable bowel syndrome. Papers were only selected if they were they were prospective or case-controlled with baseline information on anxiety/depression. Some limitations of the meta-analyses included inconsistent measures of anxiety/depression amongst the papers (some of the studies used HADS versus others that used clinical interviews).

Relevance: This is the first systematic review exploring the role of anxiety/depression in the development of IBS. The findings in the study suggest potentially providing early intervention focusing on distress management to alleviate perpetuation of the disease.

The finding: Patients with bipolar disorder with higher HADS-D scores had more GI symptoms; patients with bipolar disorder with low HADS-D/A scores had no difference in GI symptoms compared to healthy controls with similar scores.

Strengths: This is a case control study performed in Sweden of 136 patients with bipolar disorder from an outpatient affective unit and 136 healthy controls looking at affectivity and GI symptoms. The authors referenced previous work they had performed in depressed patients and noted GI symptoms being more common with anxiety/depressive symptoms. As this is a retrospective study, there is some noted reporting bias and inability to accurately predict temporal relationship of affectivity to GI symptoms. However, other studies looking at characterizing the relationship between GI symptoms and anxiety/depression have typically been carried out in inpatient gastroenterology units with more acute patients undergoing considerable distress caused by symptoms on quality of life. This study takes a different approach at studying the brain-gut relationship; looking at GI symptoms in patients with an affective disorder.

Relevance: This current study supports a relationship between affectivity and gut symptoms; many previous studies looked at functional GI symptoms and the prevalence of anxiety/depression, however in these studies, the chronicity of the illness has negatively affected quality of life. This study reminds us to be cognizant of GI symptoms as they may also indicate worsening/inadequately treated depressive symptoms.