Because Crohn's Disease (CD) has an unpredictable course, past research attempted to understand the psychosocial factors that impact disease relapse and exacerbation of symptoms (Searle & Bennett, 2001). However, this literature presents equivocal results, which may result from differing experiment designs. The present study attempts to examine the types of stressors (life events, daily, perceived) that predict relapse and define the within-person temporal relationship between stress and symptom exacerbation. In a sample of 25 CD patients undergoing a biologic treatment, an electronic diary will be used to examine the within-person variations of symptoms and stress within a day and over 8 weeks (time from initial treatment to subsequent treatment). The hypotheses are: 1. Patients who report more stress will relapse sooner compared to those who report less stress. 2. Previous reports of stress will be associated with subsequent reports of symptom exacerbation. Thus, this study will be able to not only identify if stress and disease activity are related, but also the type of stress that most impacts the clinical course of CD. In addition, within-person analyses of the temporal relationship between stress and symptoms may aid in the development of future treatment studies.