Crohn’s disease patients who suffer from depression are at an increased risk for exacerbation of their symptoms and hospitalization, according to a study in The American Journal of Gastroenterology. The findings add to evidence of a link between the conditions, and may prod further research into the mechanisms underlying the connection.

The study, “Association Between Affective-Cognitive Symptoms of Depression and Exacerbation of Crohn’s Disease,” led by Lawrence S. Gaines, assessed 2,144 adults who were part of CCFA Partners — a patient-powered, internet-based research network funded by the Crohn’s and Colitis Foundation of America.

Researchers measured a row of characteristics at the study’s start and again after 12 months. Participants were assessed using a number of surveys, including a four-item short-form depression questionnaire, and a form measuring the severity of Crohn’s disease called the Short Crohn’s Disease Activity Index (SCDAI). Information about participant demographics was also collected.

In analyzing a correlation between depression and disease activity, they found that the more severe the depressive symptoms, the worse the Crohn’s disease manifestations became. Adjusting the analyses for an array of factors – such as age, gender, ethnicity, sleep quality, smoking, as well as those disease and medication-related — researchers made sure that the result could not be explained by another variable, as the link between depression and disease activity remained.

Interestingly, the association was not linear, so that while low levels of depression were linked to a modest increase in Crohn’s symptoms, each step on the scale for more severely depressed individuals was linked to a leap in Crohn’s symptom exacerbation. In addition, the team noted that depression was associated with hospitalizations.

“Depression, defined in our study as negativity to the self and the future, is a risk factor for increased Crohn’s disease activity,” said Dr. Gaines, associate professor in the departments of psychiatry and medicine at Vanderbilt University, in a press release. “These depression-related thought processes may lead to changes in self-care, such as not taking medication or smoking.”

While suggesting that depression may be linked to a lifestyle that increases the risk of exacerbations, other issues might also be at play. Treatment with corticosteroids is a risk factor for depression, and recent studies have suggested that the gut bacterial flora might influence depression risk.

“Mind-body interactions seem apparent in Crohn’s disease but further research is needed before we understand the Crohn’s–depression relationship,” concluded Dr. Gaines.