There is a well-documented association between IBS and psychological complaints, e.g. distress, depression, anxiety. How do they influence each other? Does one more often come first? Are people down because of the pain, discomfort, and stigma of IBS? Or do people experience stress, anxiety, depression first and it contributes to IBS shortly thereafter? It’s evident that both directions are in play. But, can we learn anything by looking closer?

This well-designed case study found that IBS symptoms can foretell a down mood over successive days.

Pain And Psyche In A Patient With Irritable Bowel Syndrome: Chicken Or Egg? A Time Series Case Report, BMC Gastroenterology, 3 August 2021

This is the first study to investigate the temporal relationships between somatic and psychological variables on a daily basis. We analyzed a female patient with IBS in her mid-twenties with symptoms of diarrhea, flatulence, and abdominal pain. She reported stress-related IBS symptoms as well as symptom related fears. In most variables, strong same-day correlations between somatic (especially daily impairment) and psychological (including coping) time series were observed. The day-lagged relationships indicated that higher values in abdominal pain on one day were predictive of higher values in psychological complaints (nervousness and tension) or of negative coping strategies (catastrophizing, hopelessness) on the following day. The use of positive thinking as a positive coping strategy was helpful in reducing the pain on the following days.

In conclusion we found in the presented case that somatic symptoms [IBS] temporally precede psychological complaints.

Good reading:
– Irritable Bowel Syndrome: A Microbiome-gut-brain Axis Disorder?, World Journal of Gastroenterology, October 2014 (They call the microbiome, the collection of bacteria, viruses, fungi and other microorganisms in our intestines, a “virtual organ.”)
– The Gut-Brain Connection: How It Works And The Role Of Nutrition

A good way to cultivate beneficial organisms in the gut, ones are related to lower risk for IBS and improved mood, is to eat foods that feed those beneficial organisms. Eat starches. All kinds of starches … bananas, pasta, oats, rice, beans, potatoes. Some of that starch will barrel through to the colon where bacteria imbibe.