Research has suggested that inflammatory bowel disease (IBD) -- Crohn's disease and ulcerative colitis -- boosts the risk of mental diseases such as depression and anxiety. Meanwhile, these conditions are tied to worsening IBD.
Now, to make things even more complicated, emerging research has suggested that the gut microbiome -- not the brain -- could be a major player in spurring the mental illnesses that are linked to IBD. Other factors could also be at play.
"Is inflammation within the whole body showing up behaviorally as depression? Is it the gut microbiome? Is there a role for lack of nutrition and fatigue? The answer is probably yes," said Stephen Lupe, PsyD, a clinical health psychologist at Cleveland Clinic who treats patients with IBD, in an interview. "None of this is clear cut. The more we look at this, the crazier it gets."
Depression and Anxiety Are Especially Common
In a 2016 systematic review of 171 studies of patients with IBD, the pooled prevalence estimates for anxiety disorders and depression disorders were 20.5% and 15.2%. The estimates for anxiety symptoms (35.1%) and depressive symptoms (21.6%) were higher, with patients with active disease facing even higher estimates (75.6% and 40.7%, respectively).
