Even perfectly healthy individuals occasionally go through periods of sadness, unhappiness, or loneliness. However, when these feelings are sustained over extended periods of time and generate an adverse effect on your daily function, a depressive state is likely present. Depression is a mood disorder in which the patient experiences disproportionate sadness and an inability to experience pleasure from any activity. Depression is often accompanied by feelings of guilt, fatigue, worthlessness, and despair. Because of the chronic nature of IBS and the impactfulness of most of its symptoms, strong comorbidity has been observed between it and depression. Patients with IBS are often depressed and suffer from low self-esteem.