Studies suggest that there is a temporal relationship between depression and Crohn's disease (CD) activity. We evaluated the existence of reverse causality reflected in a possible bidirectional relationship between patient-reported CD activity and depression. To research this, we studied 3307 adult volunteers with a self-reported diagnosis of CD who completed a baseline survey that included demographics, CD activity, and depression. Crohn's disease status and depression were also measured 6 and 12 months after the first evaluation. The results of the hypothesis testing showed the most support for the hypothesis stating that depression is a stronger predictor of patient-reported CD activity. In conclusion, our findings suggest that CD patients' negative self-regard is clinically important to understanding change in patient reports of their CD activity. Gastroenterologists should screen for affective-cognitive symptoms of depression in CD patients. Evaluation and treatment of depression may improve the course of CD.