Mental health disorders, and in particular depression and anxiety, are more common in inflammatory bowel disease (IBD) compared to the general population. Epidemiological studies suggest a bidirectional temporal relationship, where IBD is a risk factor for future development of anxiety and/or depression, and vice versa. Historically, the link between IBD and psychological morbidity was thought to be mainly a reactive response, where IBD symptoms and chronic illness lead to mood disorders and anxiety. However, recent studies highlighted the “gut-brain axis,” a network of neuronal, humoral, metabolic, and microbial changes that may explain a causal reciprocal relation between brain and gut processes, regardless of symptoms. Studies have shown that mental health is an important contributor to quality of life and clinical outcomes in IBD patients and should be addressed as a part of the holistic care in IBD. The ongoing research key for future novel diagnostic and therapeutic approaches that would improve patient care.