The four stages of Irritable Bowel Syndrome (IBS) can be divided into early, moderate, severe, and very severe. During the early stages of IBS, patients may experience mild symptoms such as abdominal pain, bloating, and changes in bowel habits. As the condition progresses, the symptoms become more severe, with more frequent and intense abdominal pain and cramping, changes in bowel movements, and fatigue. During the moderate stage, the symptoms become more frequent and more severe, and may include increased abdominal discomfort, diarrhea, and constipation. As the condition progresses further, the symptoms become even more intense, and patients may experience weight loss, nutritional deficiencies, and an inability to perform normal activities. Finally, in the very severe stage, patients may experience more severe and disabling symptoms, including the inability to have normal bowel movements, and extreme fatigue.